Chair-man of the board

This is part 2 of a series on my new Adirondack chairs. Click here to read the first part.

After a month in the kiln, I picked up my Monterey Cypress lumber at the mill in Paso Robles and drove it home on the roof of my VW Touareg. I was dodging rain flurries for this pick-up, and I really didn’t want the wood to get wet while in transit. I managed to get it to my shop without getting any rain on the boards.

After letting it sit in the shop for a week, I took my planer out into the main work area and connected it to the dust collection pipe there. I then planed four boards to .875 inch thickness and the remaining boards to .75 inch. This would allow me to run them through the drum sander to get them to the finished dimensions.

No good deed goes unpunished though! A rehabilitation of the drum sander was needed, as I don’t use it very often, and it has been a long time since I replaced any of its parts. I bought a new feed board belt from Amazon, and installed it. Since it was an after-market part it didn’t fit perfectly, so I had to disassemble the table and machine slots into two of the original parts that didn’t allow enough horizontal adjustment to make the new belt fit and work correctly.

The Cypress wood is quite brittle, and it is pocked with many small knots. The boards also have a tendency to split along the grain, making a lot of the wood unusable. I cherry-picked the boards (Cypress-picked?) for areas from which I could cut my largest boards. For this I printed my pattern on my Epson ink-jet printer, then used the print-outs as size templates on the lumber. I put pencil marks on each board to indicate which parts would come from which boards.

These were the rough cuts of the lumber. On top of each pile is the ink-jet print-out showing the part, and the required quantity. I spent a couple of days sorting through the boards to find the right pieces for each part.

Once I had determined which boards were for which parts, I cut them to rough size. Then I set up a jig for machining the parts on the CNC router table. I put my T-slot spoilboard on the bottom, and them added low-profile aluminum clamps on the spoilboard, supplemented by quoins that expand to hold the rough cut boards in place for machining.

The trick is to cut the parts with minimal or no damage to the spoilboard. To accomplish this I set my Z-axis (up-down) to zero on the spoilboard itself. That way I could write the cutting code never to cut below zero. This worked pretty well, though there are some cutting marks on the spoilboard now, after all the work was done.

…and these are the pieces after being cut on the CNC machine (the legs on the right were cut on the table saw). All of these parts were made with tabs that held the cut part to the parent board. Those tabs are cut after machining, then sanded off on the disk sander. Any part that comes in contact with the person in the chair also got a half-round routing on a manual router table to soften the edges of the chair where arms and legs rest. All of the seat boards and the arm rests were treated this way, as were the back slats.

My jig system allowed me to cut a variety of boards with a common lower-left X-Y starting point. I had only to change the clamps and quoins to hold the top and right ends of each board according to its size. I used the CNC machine mostly on the complex parts – the armrest boards and the waist and foot boards where the vertical slats are affixed. For the slats themselves, I machined only the last few inches at the top of each, and the inverse-heart shape on the C-slats. This required cutting out the negative part only. To do this I copied the shape of the heart and made it into a negative shape that I programmed the machine to cut out of the slat. This saved time.

This is the C-slat. Its round-over head and heart-shaped detail were machined on the CNC machine by cutting only the negative areas shown here in magenta. I had prepared the boards on the table saw.

Almost all the parts I machined on the CNC machine were cut with tabs, those being little bridge connections that attach the part being cut to the parent board. These are designed to keep the board you are cutting from getting thrown out of position by the end mill (12,000 rpm!) that is removing material from that board. Tabs prevent damage to the part, to the machine, and potential injury to the operator in the most dramatic circumstances (this seldom happens).

A few of the boards I cut had small cracks that grew into large cracks as the boards were machined. Internal tension in the boards was significant, and sometimes that tension was released as a widening split. To correct this, I glued several cracked boards by injecting waterproof Gorilla Glue into the cracks, then clamping them back together, and allowing the repaired board to dry overnight. This made it possible for me to recover several boards that would otherwise not have been usable.

I removed all the small tabs using my disk sander, and I hand sanded every board in preparation for assembly. This is when the fun starts (just three months into this project!). I bought a can of Varathane acrylic exterior satin varnish for the chairs, as my plan is to leave them in their “natural” wood appearance. Experience has taught me that the wooden parts of any project must be coated or painted prior to assembly, as water has a clever ability to get between connected parts by capillary action, then rot sets in. With that in mind, I opened the can of varnish, and I painted the opposing surfaces of boards that will be bolted or screwed together later. A trick here: if time allows, it’s nice to let the varnish get sticky, then assemble the parts while they are “green” – this makes the seal more effective.

Once the finished pieces were machined, I sanded them, then painted the points where the boards touch with Varathane water-based satin varnish. When it was still sticky I bolted the parts together with stainless steel carriage bolts. This technique keeps water from getting into the joints between the pieces.

I bought a quadrillion dollars’ worth of stainless steel hardware for these chairs – about $35.00 per chair – and it is beautiful stuff! I bolted the legs together first using carriage bolts, washers and nuts, then positioned the frontmost seat board and the rear “foot” board, where the vertical slats are attached. Once those defining parts were in place, I attached the arm rests to the shoulder board with carriage bolts, and affixed those to the leg tops, using small 90-degree braces cut from the 0.75 inch stock.

Now the chairs are ready to be completed! More on that in the next post, which will come in a few weeks.

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A new Adirondack chair for 2023

In the summer of 2014 I built a couple of Adirondack chairs for our back deck. I wrote about it here.

These were made of oak, painted with primer, then assembled and painted again to make them as weatherproof as possible. All of the hardware is stainless steel, making them less likely to rust. They are still doing well, and they have withstood the test of time and the elements.

My wife and I decided that we need two more for our upstairs balcony, a space that is smaller, and will require me to modify the chair design to scale it down so that the finished chairs are appropriate to the space. The new chairs will be narrower, not quite as tall, and will be made of thinner boards. Instead of 3/4 in. oak boards, I am planning to use Monterey Cypress in 5/8 in. thickness; the structural members (legs mostly) will be made of 3/4 inch boards of the same wood.

This is my Adirondack Chair, v.2. It will be made of Monterey Cypress.

I have purchased the lumber from Pacific Coast Lumber in Paso Robles, California (about 35 miles north of my city). They have sawn the boards from trees that were taken from storm damage at Morro Bay State Park (about 12 miles from our home). I have never worked with Cypress before, but I am told that it is “semi-hardwood” and that it is especially resistant to weather damage.

The boards are currently being dried in the kiln at the lumber company, and in a couple of weeks I will be able to pick them up and take them to my shop. If they are pretty enough, I plan to make the chairs and then finish them with polyurethane varnish so as to show off the natural qualities of the lumber. If not, I will paint the chairs with two coats of exterior paint. As before, all of the hardware will be stainless steel, which I have already procured from McFeely’s in Harrison, Ohio (best supplier of screws and hardware in the U.S.).

I plan to cut all the parts on the CNC router, machining all of the shapes, and drilling all the holes, then I need only sand and assemble to make the final chairs. I have also simplified the construction a bit, allowing screw heads in the seat boards and vertical slats to show (I plugged and sanded the previous chairs so that the screw heads are invisible).

And, as I did with the first edition, I am machining a heart shape into the vertical slats. It’s a nice design. Unlike the previous models, though, I am not making a plywood prototype. I’m going straight to finished chairs and hoping that my design is effective, and that the finished chairs are comfortable. We’ll see!

These are the back slats showing the hearts machined into the boards.

I will also make a pair of companion “Adirondack tables” to sit next to the chairs to hold our drinks when we sit out on the balcony in the evenings.

I have seen a lot of similar chairs in stores, and I have tested some of them to see if I like the comfort and construction. So far I like mine the best. Cost – my chairs are not going to be cheap. The stainless steel hardware alone cost more than $100, so I’m off to a good start in the expense column. The lumber, being custom milled and kiln-dried, is also expensive. I am paying for exotic wood that is both handsome and functional.

My job will be to plane the boards to their rough thickness first, then drum-sand them to finished thickness before I begin the machining. I’ll make both thicknesses of finished boards from the lumber I am buying from the mill, all of which will be the same original thickness. Once the boards are ready, I will clamp them into a jig on the CNC machine and get to work cutting the finished parts. Some of the edges will also be round-over routed for comfort. Anywhere arms or legs touch the chair will be smoothed with the round-over; all of the other edges will remain sharp.

This is the side view in Adobe Illustrator. It shows the way the chair will be built, including machine screws and seat slat positions. I think it will be a handsome piece of work.

As always, I started in Adobe Illustrator. I revised the original chair design by scaling it down a bit, then changed the angles slightly to make the chairs less-inclined (to fit in the limited space). The new chair design has many things in common with the earlier models. I planned it to cut easily out of eight-inch boards with a bit extra for clamping the boards. Machining will be relatively easy as all of the cuts can be made with a standard 1/4 inch end mill cutter. This makes it possible to cut the pieces quickly and with very smooth finished surfaces. I’m looking forward to this part of the project, and have made some clamping jigs to hold the boards as they are cut.

I’ll document the steps taken in construction and will write about it here. Keep an eye on this space in the coming weeks as I jump into this project.

To read the next part of this story, click here.

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Dancing in the laser light fantastic

This is part 2 of my article about building a fixed positioning laser on the CNC machine. To read the first part, click here.

I had decided to make the final fixed laser with a bracket made of aluminum.

In the weeks in between, I practiced cutting aluminum with various cutters, various speeds, and various feed-rates. This was not my first attempt to cut aluminum; I have done it successfully – and unsuccessfully – before, and I felt that I could make these parts perfectly with my experience in aluminum cutting.

I bought a plate of 3/8 in. aluminum and mounted that on the spoilboard. Then I transferred my drawings into V-Carve (the software that I use to make the G-Code instructions for cutting). V-Carve is capable of importing vectors from Adobe Illustrator (and perhaps other applications) and making them available to its drawing environment.

In Illustrator, I had made a roughing cut line 0.005 in. away from the final dimensions, and another on the final dimension lines. This is easy in Illustrator with its Offset Path function.

I watched several YouTube videos on how to cut aluminum on a CNC machine, and I read as much as I could find on the subject. I decided to use a single-flute 1/4 in. end mill and turn it at 10,000 rpm. I chose to run the cutting tool at only 10 inches per minute. This was a compromise between getting the “chip load” right, and not driving the mill so fast that it would burden the cutter and the machine or get too hot and clog up with aluminum chips.

I experimented on a scrap first, and was very pleased with the results. I decided to make the final pieces (though the pessimist in me had ordered enough aluminum to do it twice).

Then, armed with a can of WD40 to be used as a spray lubricant and coolant, I set up the machine and started cutting. I was taking very small vertical steps into the aluminum (0.05 in.), again not wanting to put too much load on the cutter. It was working quite well, so I continued with the process.

Here is my single-flute Vortex end mill cutter working its way through the aluminum plate. The blue and orange device is the nozzle of my compressed air blast aimed at the cutter. This helps to clear chips from the project as it is machined.

It took almost an hour to make the two parts, but the result was perfect. My surfaces are smooth, and the parts fit together nicely.

I then used my vertical positioning jig to drill the two tap holes into the ends of the horseshoe part, and used “pecking” to drill the holes without breaking the small end mill cutter (0.125 in.). The vertical jig was created by cutting a hole through the spoil board on the machine, and adding T-slot grooves on a bracket that runs vertically under the table surface. This allows me to clamp work on-edge and machine the end of that work. I locked the horse shoe part in the jig and did the drilling with the precision I needed for this step.

This is the aluminum after the milling was complete.The tabs, circled here, were designed to keep the parts from getting loose during the machining. The tab in the center was put there to prevent the scrap piece there from being thrown by the machine while cutting the lower part. I would not do it this way again, opting instead to make the parts without tabs, and clamping the work differently.

My biggest mistake in milling the aluminum was using tabs to hold the aluminum to the plate while it was being machined. Tabs are small sections along the edge of work that are left uncut to hold the work to the larger material. These tabs ended up being too big, and it required quite a lot of work to remove them from the finished parts. In the future I will change my strategy to machine the parts so that I can change the clamping mid-project, and leave no tabs at all.

This is the nearly-finished bracket. The sanding scratches on the top were removed with some additional elbow grease and then the parts were buffed to a fine finish.

Nonetheless, the parts turned out nicely. After sanding the tabs off and doing a light finish sanding pass, I buffed the parts to a near-mirror finish and mounted the bracket onto the spindle motor, taking the place of the wooden prototype.

I went through the alignment process again, and when finished, I squirted a blob of hot-glue into the set screw holes on the laser to keep them from vibrating out of position. The hot-glue is removable in case I need to change the alignment in the future.

Here is the laser mounted on the bracket. I was able to align it perfectly by sliding the front plate relative to the horse shoe bracket with the slotted holes. Once aligned left-to-right, it was only a matter of aligning the laser with its internal set screws to center it on the X-axis of the cutter.

After completing this project I lay awake wondering if I had overlooked something. I thought about one possibility, which I call laser parallax. Adjusting the two setscrews on the laser obviously moves an optical element inside the laser. Is it moving the laser itself? A lens? I don’t know the answer, but I do have a potential parallax error in my positioning laser system. Will either axis shift as the spindle motor (Z-axis) moves up and down?

The answer to this question was found by testing the system. I scratched an X on my aluminum plate, then positioned my positioning laser exactly centereed on the X. Then I ran the spindle motor upward to the top of its track, and downward to the bottom. By observing the position of the laser beam relative to the cross-hair scratches, I determined that I was in big trouble. The laser remained perfectly aligned along the X-axis, but it wandered by an incredible 1/4 inch on both sides of the Y-axis scratch.

I marked the center of vertical travel on the spindle motor mechanism and aimed the laser at the cross-scratches. Then I moved the motor upward and downward while adjusting the two positioning set screws in the laser body. It was way off. I put various shims between the mounting rail and the motor body and tested it again. It got better, but it never got perfect. So I walked away for the night.

In this illustration I have inserted a shim between the top of the laser bracket and the mount. This did not work very well, as it only aligned the laser at one position on the Z-axis. I later discovered that by removing the shim and aligning the laser by rotating its body in the bracket, and adjusting the two internal set screws, I was able to make the laser track perfectly along the Z-axis.

While studying a photo of the laser in the Amazon site, I noticed a fourth set screw in the device that I hadn’t noticed before. That set screw allows the body of the laser – a perfect cylinder – to be rotated inside its mount.

I removed the shims from the mount and put the laser back into its bracket. By rotating the cylinder I was able to move the laser in a circle on my aluminum aiming plate. By adjusting the other two positioning set screws I was able to move the beam until the spot of the beam did not move as I rotated the cylinder. This meant that I had found the optical center of the laser.

Once that center was achieved, I had only to position the entire bracket left and right until the beam crossed the X-axis scratch line. When it did, I tightened the screws on my bracket and tested the up-down movement of the spindle motor again. This time it remained perfectly centered on my scratched cross lines from top to bottom. Perfect!

I tightened everything up again, squeezed two blobs of hot glue into the set screw holes and started using my new positioning laser for my work.

I now have an effective tool for positioning with great precision on the CNC machine. I used it earlier today to align a long maple board on the spoilboard of the machine. I ran the laser to the edge of the board so it split the edge, half spilling over and drawing a line down the board. I ran the laser along the length of the board to ensure that it was straight before cutting it into a complex moulding.

I am extremely happy with this tool modification. I learned a lot and I added a laser that I am sure will be used many times while doing set-up and measurement on the machine.

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Affixing a laser to the CNC machine

My friend Bryn and I own a CNC router. We have had it for years, and it has undergone a couple of upgrades. It started life as a CNC Machine with a DeWalt router motor mounted on it, providing adequate, but not impressive cutting speed and depth. We each burned up a DeWalt router before we decided to upgrade to a more powerful spindle motor. (No offense meant to the DeWalt router – it’s a fine power tool, but it is not up to the task of CNC machining.) We updated with a 220V spindle motor that is much more powerful, and which provides more power for cutting.

This is the CNC router made by Avid CNC. The computer in the foreground is a Sony laptop with a separate larger display. Both displays show the same thing. We run V-Carve and Mach 3 software on this machine. This image shows the CNC with its first or second DeWalt router motor. We burned those up with too much force, and perhaps poor choices of speed and chip load. The routers have been replaced with a 3 HP 220V spindle motor.

The machine was built from parts available from AVID CNC, formerly known as CNC Parts. Ours is just over 4 x 8 feet in size. We have it hooked up to our shop dust collection system, and we have a compressed air line attached to the spindle to deliver an air blast to the cutting tool when needed.

When we first got the machine, I invested in a laser positioning device (from SDA Manufacturing, LLC) that can be mounted in the spindle, allowing us to make extraordinarily accurate positioning and measurement settings. That laser has served us well. To use it, I mount it in a 1/4-inch collet on the spindle, turn it on, and then move the spindle to the position I want to measure or find, and set the machine accordingly. When finished, I take it out and replace it with the cutting tool I intend to use.

That’s not difficult, but it’s a bit tedious. I have wanted a fixed laser positioning tool on the spindle for a long time, making the laser a permanent part of the machine. I want to be able to turn on the laser positioning tool, move the machine, and then get to work without having to change the laser out and the cutter in.

This is the upgraded spindle motor. My project was to make a fixed positioning laser and attach it to this motor.

There was no commercial laser device available for our machine so I designed one myself. I determined that I couldn’t drill into the spindle motor to mount a laser there, but I thought that I could make a bracket that attaches to the spindle motor base that would hold a laser in position.

I started looking for small battery powered lasers appropriate to the task, and found one that would work. It’s a gun-sight laser, designed to be attached to the barrel of a pistol or rifle. Moderately powerful, it looked like it would work nicely for the application at hand. I ordered it from Amazon. I also discovered that when it comes to rifle accessories, there are several that attach using a more-of-less standard attachment rail. I bought 10mm of that rail also. The laser is designed to clamp to that rail.

(SDA Manufacturing makes a version of their laser that is possibly better than mine. It comes with a mounting bracket, has microscopic adjustments for alignment, and a permanent power supply instead of batteries.)

This is my prototype laser mount made of Ipé wood. In the spindle at the bottom is the SDA spindle-mount laser. That tool is an exceptionally accurate device that fits into the spindle where a cutter will go when the work starts.

My plan was to attach the rail to my bracket, attach the laser to the rail, and have a fixed positioning laser on the machine. Simple!

The laser arrived and it was nearly perfect, but it was much too powerful and the beam too big and bright for the application. Bryn has a Glowforge laser cutting machine, so I asked him to laser-cut some very small apertures in black acrylic material, and I experimented with those as fixed apertures on the gun-sight laser. The smallest one – 0.24 mm – worked perfectly. It both attenuated and limited the laser beam to one that would work in a distance measured in inches. I glued the aperture to the front of the laser body with Superglue.

I designed a bracket that would go around the motor base without drilling any holes. It consists of a horseshoe piece with a faceplate that holds the laser vertically on the side of the motor. It is possible to align this laser with the X-axis of the cutter (left-right), which makes operation much simpler.

The fixed laser pointer is shown here as I made it. Note the slotted holes on the front plate, those allowing the laser to be positioned exactly inline with the X-axis. The mounting holes were drilled, then threaded for 8-32 machine screws that hold the two pieces together and clamp them to the spindle motor. Note also that the slots are slightly larger than the screws (0.175 in. vs. 0.125 in.) to allow some rotational movement in adjusting the laser on the machine.

I drew my bracket in Adobe Illustrator – my go-to application for these projects – and came up with the two-part bracket I needed. My plan was to cut it out of aluminum plate, but for prototyping I decided to make the first edition out of wood. I have a stock of Ipé wood in various sizes. This is a Brazilian “Walnut” of the genus Handroanthus. I have years of experience with this wood, and I have a love/hate relationship with it. I love it because it’s beautiful and very hard. I hate it because it dulls every blade that touches it.

For this project it would be perfect, because it is so hard. It machines reasonably reasonably easily, and can be cut with standard milling tools. It is quite brittle, but exceedingly strong.

I planed a board to 0.375 in. thickness and mounted it on the base of the CNC machine. From there I did my machining to make the two pieces for my laser bracket. Both parts have threaded holes for the final assembly, and I drilled the appropriate tap hole sizes for those holes into the wood. Making threads in Ipé is easy. Once the tap holes were drilled, I dripped Superglue into the holes and allowed it to harden. Then I ran my tap into the hole and cut the threads. This worked very well, and the threaded holes work nicely.

I mounted the bracket onto the spindle motor and tightened it at the base of the motor. From here it was stable. Then I mounted the gun-stock bracket to the wooden bracket and tightened it in place.

I mounted my new laser onto the bracket, then began to align it to the spindle. I drew a black felt pen line on an aluminum plate, then, using an awl, I scratched a fine line down the center of that black line (along the vertical Y-axis). I put the positioning laser into the collet, and aimed that on the scratched line by moving the gantry left and right (X-axis) until the reflection of the positioning laser was perfect. I moved the aluminum plate carefully until the laser reflected the same along its vertical (Y) axis. Then I moved the positioning laser to the upper end of the scribed line.

Then I turned on my newly mounted laser; its beam reflected off the aluminum plate, but it was about 1/8 inch away from the line. That laser has two hex screws for positioning, so I inserted a hex wrench into one and adjusted the beam slightly toward the line. Then I switched to the other set screw and adjusted it further. Within a few minutes I had both lasers reflecting perfectly along the X-axis line.

The next step was calculating the Y-offset. With the two lasers aligned on the X-axis, I scribed a cross-line where the spindle-mounted laser beam struck the X-axis line. Then I zeroed the Y-axis in software.

Here the laser beam is hitting the cross-scratches on the aluminum plate. With these marked, I was able to position the new fixed laser correctly, and also to measure the Y-offset with precision.

Noting the Y-axis position, I moved the spindle along the Y-axis until the new fixed laser reached the cross-scribed line and took note of the new position. Subtracting one from the other I determined the offset to be 3.0453 in. That is my Y-offset for using the new fixed laser beam for positioning.

My method for using the new fixed positioning laser is to point it where I want it, then go into the second menu of Mach 3 (where I can enter G-code commands) and issue a G0 Y3.0453 command, which moves the spindle the distance of the Y-offset. Then I switch back to the main Mach 3 menu and reset the Y to zero again.

Over a period of days, I was successful in using the new fixed laser to position the spindle. At one point, though, I was realized that it was not positioned correctly. It was pointing to the left of the edge of a board when it should have been right on the edge of that board. I took out my scribed aluminum plate again and re-ran the alignment process. I think that the positioning laser’s set screws vibrated off position (I’ll come back to this).

That error notwithstanding, I decided to make an aluminum version of the bracket and make it a permanent part of the system.

For part two of this story, please click here.

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Gliding into a saw restoration

This is Part 2 of my story about restoring an antique Hammond Glider “TrimOsaw” for the Shakespeare Press Museum at Cal Poly. To read the first part, click here.

This is my illustration of the side of the restored saw, showing the non-existent belt guard. That guard would come into existence a bit later – read on!

I got to the point of removing the aluminum nameplate from the front of the saw. This was delicate work. I ground the heads off of the four rivets that held that plate on the machine with a Dremel mini-grinder.

This is the aluminum nameplate after removal from the machine. It had endured decades of damage, but I managed to remove it, and then later reinstalled it on the saw. It’s a very nice piece of 1950s art.

Drilling-out the holes of those rivets proved nearly impossible. I drilled and I drilled and I got nowhere. After consulting with a machinist friend, I invested in two 1/8 in. carbide drills at $30 each. These, he assured me, would drill through anything. The rivets used by Hammond were made of stainless steel which cannot be drilled easily with conventional twist drills. The man who sold me the carbide drills promised me that I needed two because I would break one. He was right. I made three flawless holes with one drill, and then broke a drill on the fourth. So, each hole cost about $15 to drill.

Removing the several coats of paint was a dirty job, most of it done with an industrial angle grinder. The process left the shop filled with acrid smoke and a cloud of particulate. Those N95 masks have purposes other than virus protection! Once I had the paint removed, I rolled the machine into the paint booth and sprayed it with the special green paint I had chosen.

After two coats of paint, and a day for drying, I started to reassemble the machine. I installed the motor, replaced all the conduits and then wired the machine. Because I am obsessive about these projects, I had drawn detailed wiring diagrams, and acquired the necessary parts to do the job professionally, with everything compliant with current electrical codes.

Because table saws are inherently dangerous, I installed a magnetic motor switch on the saw. This ensures that the saw will not restart after a power failure. I also installed a massive master power switch with a lock-out, so that the machine can be locked off to prevent unauthorized or untrained people from operating it.

I used stranded copper wire throughout, as required for any wiring in flexible conduit. This makes it possible for the motor to move (it moves when the depth of cut is changed) without bending solid wires. Again, this is a code requirement as well as a practical idea.

I completely rebuilt the micrometer miter gauge, cleaning out dirt and chips from its internal workings. It is made of chrome-plated steel mixed with aluminum parts, so it had not rusted over the decades in storage. It is gleaming now. The blade guard is cast aluminum, and it showed a lot of wear. I wire-brushed it, then polished it on a buffing wheel, resulting in a concours d’elegance appearance.

Completing the work, I wire-brushed the work lamp, which is a gooseneck of chrome-plated steel. The small amount of rust came off easily, restoring it to like-new appearance. That work lamp does not have a ground wire, so I checked the code, and discovered that work lights often do not require a separate ground wire. When connected to the body of the machine, the steel itself provides an adequate ground. That was lucky because I could not have fished a new ground wire through that gooseneck.

The last part on the saw was the belt guard. It had one when it was manufactured, but somewhere that had been removed and discarded. I found a copy of the original instruction manual online, showing a photo of the machine, but not from the side with the belt guard. There are two steel studs on the machine that obviously held a guard in place, so I designed one in Adobe Illustrator then figured out how to make it.

This is my belt guard design. It’s composed of two parts: the front plate, which I machined out of 1/4 inch Alupanel aluminum laminate material, and the outer guard, which was water-jet cut from 18 gauge sheet steel, then bent into the right shape, and riveted to the front plate. It turned out very nicely.

I began by making one on my CNC machine using a Sharpie marker and running the machine to draw with that marker on a sheet of corrugated board. Then I cut that out and positioned it on the machine. I made several drafts of the guard that way, until I felt I was ready to make the final guard out of aluminum plate.

The flat plate was the easy part, while the curved sheet metal part was more complex. It had to envelope the belts without touching them at any point in the travel of the motor and pulleys. The second step was to cut the belt plate out of a material called Alupanel. This is a material made of two thin layers of aluminum sandwiched with a layer of plastic between them. It is light, moderately strong, and it can be bent, rolled and machined like aluminum, but at a fraction of the cost and time needed to do the work in solid metal. I bolted the first part on to the machine and tested it through the range of motor movement. At the small end, it hit the machine’s lift mechanism, so I modified its design to prevent that. In the end, I had made three versions of the plate. The third was successful.

For the sheet metal I needed strength and bendability which I could not get from Alupanel. I sought the help of my machinist/welder friend Hank Van Gaale. He suggested sheet steel, and water-jet cutting. I had been prepared to cut sheet metal with a pair of shears, but I was excited to see and use water-jet.

My belt guard is comprised of the Alupanel front plate, and then it has the sheet steel formed into a two-inch protector that covers the V-belts to keep fingers out. I cut a 1/16 in. groove in the front panel, expecting the sheet steel to be inserted into that groove. Along the edge of the same sheet steel I put fold-out tabs with small holes for rivets to be placed, holding the guard at 90 degrees to the front plate.

I designed the sheet steel part in Adobe Illustrator, including three folded hems, all of the rivet tabs, and the parts that sit inside the groove. I submitted the drawing, formatted in AutoCAD dxf format to the water-jet company. There, it was opened in their machining program, positioned, and prepared for cutting.

This is my Adobe Illustrator drawing of the rolled steel guard part, cut on the water-jet machine.

The water-jet is a CNC machine with a .014 in. diamond orifice that supplies water with garnet abrasive at a pressure of 50,000 psi. This jet of abrasive liquid cuts through the steel (or nearly any other substance) as if it’s not there. Cutting my piece took less than three minutes.

To view a short video clip of the water-jet machine cutting this part, click here.

We used 18 gauge steel (0.04 in.), so folding the hems was easy using a bending brake, and rolling the curve was also easy, using a rolling machine. The last part was folding the tabs over 90 degrees with a pair of pliers, then affixing the steel on my front plate, drilling holes and attaching the tabs with pop-rivets.

In the end, the guard is quite handsome. Perhaps it’s too fancy, but I didn’t have a plan for it when I started, and water-jet cut steel worked perfectly. The guard is now mounted on the machine, and the project is finished. It’s now back in the museum at the university. There, I hope, it gets some use cutting slugs made on the Linotype machine.

This is the finished, fully restored Hammond Glider saw. You can see the finished belt guard here.

An addendum: I awoke from a dream night-before-last. I was dreaming that the saw project was not finished. Where there was once a rolling trimmings box under the saw there is nothing now. Somewhere that cart was lost. I had left the space open. But, when used, the trimmings from the saw fall down through the machine and onto the floor. That is unacceptable. So, today I remedied that by building a drawer that slides into the opening under the saw. It slides out over the rolling base frame, and allows for the removal of the trimmings from time to time. Now the project can really be declared finished!

Addendum, February 12, 2023

After I delivered the saw to the museum, I ran it to demonstrate it to the student curators, and it didn’t run very well. I made note of the problem, which appeared to be V-belt slippage, then I disassembled the back-end of the saw and took the motor mount plate off the machine. Back to the shop, I put it on the CNC machine and cut four slotted holes in the plate where it mounts to the saw body.

These slotted holes will allow for the motor to be moved about .5 inch front-back to add or reduce tension on the V-belts. I think this will solve the problem of power getting to the blade of the saw.

While I had it apart, I installed a new start capacitor on the motor (it didn’t need one, but who knows?) and I changed the motor wiring from a (not very) flexible oil-tight conduit to a rubber insulated cord with strain reliefs on both ends. This makes the motor much more flexible, and will allow it to hang on its bracket, providing better V-belt tension. I think these two modifications will make the saw work better. And then my project will really be done!

Posted in Graphic Arts people, History, Printing and Printing Processes, Restoring antique printing machines, Technology | Tagged , , , , | Leave a comment

Restoring that ol’ saw – a Hammond Glider

Now that the Smyth machine is working, I decided to take on a new project.

Last fall I offered to restore a 1960s era Hammond Glider TrimOsaw for the Shakespeare Press Museum at Cal Poly. This machine is best described as a precision table saw for cutting metal type, Linotype slugs, Ludlow slugs, and similar materials used in typesetting. The machine has a 7-inch blade and a precision micrometer miter gauge for setting the line length in one-point (0.0138 in.) increments. It also features a precision blade lift that can be adjusted in 1-point increments.

This is the Hammond Glider saw as I received it. You can see that I’ve started the restoration by removing the old electrical equipment, an unnecessary transformer, and all of the wiring. I left the flexible conduits in place, and eventually fed new stranded wire through them.

In every other way, it’s a small table saw.

The company that made it, Hammond Machinery Company, is still in business in Kalamazoo, Michigan. They now make industrial abrasive machines for smoothing parts and surfaces. They are still in the same building as they were over 100 years ago when they began making machines. Unfortunately, unlike the Smyth company, they don’t stock parts for their 20th century printing industry machines (I asked).

With the help of my friend D.K. Philbin, I moved the machine from Shakespeare Press Museum at Cal Poly to my shop, 10 miles away.

Once there, I tore it down and began work. First I removed the electrical work that had been re-done in the 1970s. The original saw had a 240 volt connection, and then a transformer to power the 110V work lamp on the machine. I found this ironic since you don’t need a transformer to get 110 volts on a 240 volt circuit (you take one hot leg and the neutral, and you get 110 volts!). I put the old transformer into e-waste.

The machine had been painted with a brush in an awful green-gray color. I found the original color underneath, and I bought some Cedar Green paint that closely matches the original color of the machine.

In this image you can see the 8 x 10 inch block of lumber holding the motor in place. I removed this and replaced it with a machined aluminum plate. In this image you can also see the micrometer miter gauge on the top-right. This gives tremendous accuracy to the machine, allowing cuts to be made with 1 point (0.0138 in.) precision. The blade lift has the same increment of movement.

The saw is made of cast iron, and it weighs a healthy 400 lbs. It’s very hard to move, even using a hand truck. Once at my shop, I found that lifting it with an engine hoist worked, and that made it possible for me to do it alone. My first order of business was to mount it on a rolling base that will forever be under the machine, allowing it to be moved when necessary.

The wiring was functional, but not “to-code” – meaning that someone had put solid copper wire in flexible conduits, used the wrong colors of wire, and had simply ignored the requirement for a ground wire to the motor, grounding it to the frame and the building circuits.

The V-belts were old and tired. The electric motor was in serviceable condition, but it was mounted on a block of 8 x 10 inch wood with bolts. This made no sense, so I removed it.

The working surfaces of the machine – its tables – had been abused by workers who had put heavy, sharp objects on top many times, putting hundreds of small dings into those surfaces. All of the unpainted surfaces were covered with a light rust. That’s where I started on the cosmetic work.

Using silicone oil as a sanding slurry, I attacked those surfaces with an orbital sander mounted with emery paper. In successive passes I smoothed those surfaces down to a nice sheen, and I removed much of the damage. When finished, I applied a paste wax to those cast iron surfaces to make them more resistant to rust, and to make them slippery, which enhances their smooth and safe operation.

I tested the motor, but it didn’t work correctly. It would start, run up to speed, and then slow down, over and over. Alternating-current induction motors like these are surprisingly simple devices. They have very few moving parts (a rotor and a centrifugal switch) and almost nothing can fail inside other than the centrifugal switch and the capacitor. The capacitor tested fine, so I adjusted the centrifugal switch. It worked better, but still not perfectly.

The motor needed a new mount to replace the block of wood that held it for 60 years. I machined one out of aluminum plate on my CNC machine, and then painted that plate to make it look nice. Once the paint was dry, the motor was ready to go back on the machine.

I took the motor apart four times, each time making a different mistake in reassembly. I drew a wiring diagram of how it was connected when I started, then consulted the wiring diagram that is printed on the inside of a metal plate on the motor. I kept wondering about the brown wire, which was connected to one post and which allowed the motor to run on 110 volt power. The diagram showed that wire connected to a different lug. I studied it, and determined that it could not be connected there, so I left it where it was. Surprisingly, the diagram printed on the motor itself is in error.

I wired the motor for 110 Volt operation (left), but discovered that the diagram on the motor body is incorrect. The brown wire shown connected to 5 cannot go there (it doesn’t work). Instead, the brown wire must be connected to point 3, where it does work.

The motor was of an era when the electrical code did not require a separate ground wire from the motor to the circuit. I suppose the manufacturer assumed that the motor would be bolted onto a metal plate, which would be bolted onto another metal plate, and that to the frame of the machine, all providing electrical and mechanical grounding (They obviously didn’t consider the 8 x 10 board that held the motor to the machine.) I added a separate ground wire to the motor conduit, and attached that to the motor body, and then to the electric box on the back of the machine.

This is the complete wiring diagram, showing all of its connections. The magnetic switch ensures that the saw cannot restart after a power failure without the operator turning it on again. Click to see it at twice the size.

I replaced the V-belts with two of the same size and brand, ordered from the local auto parts dealer. Then I removed the beautiful TrimOsaw nameplate from the front of the machine with extreme care. It was affixed with rivets to the cast iron body. I ground the heads off the rivets with a small portable grinder, and eventually the nameplate came free with minimal damage.

Part II, where the saw comes back to life, is available here.

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The Smyth book sewing machine is now running!

Some of you may recall my obsession with a 1935 Smyth book sewing machine and all of the steps it took to restore it and get it running again.

This is the now-completed Smyth book sewing machine in the Shakespeare Press Museum.
The museum is part of the Graphic Communication Department at Cal Poly, where I taught before my retirement.

After my return from Germany last September, I worked a lot on that machine and got it to the point of actually sewing signatures of a book into book blocks. There are still some small adjustments to make to get it working perfectly, but after over three years of work, it’s finished and I’m mighty proud that it sews books.

That machine, a 1935 Model 12 Smyth book sewing machine, had sat on display in a glass case at the California State Printing Office in Sacramento for about 20 years. The lubricants in the machine had turned to a waxy adhesive, and the clutch was locked in the engaged position by the stiff goo. The wheels wouldn’t turn; the screws wouldn’t budge. The motor was dead.

It also had outdated and illegal electrical wiring, with exposed high voltage contact points that were not to-code in the 21st century. I remedied those electrical problems by putting the old motor and speed regulator into e-waste and starting over with a new totally-enclosed motor and a fancy variable-frequency drive to control it.

If you want to read about that part of the project, it is serialized here.

I spent the better part of three years working intermittently on this machine.

In late November, 2022, I demonstrated the Smyth machine to a class of 37 young women studying Book Design Technology in the Graphic Communication Department at Cal Poly. During that demonstration I broke a part on the machine – a result of allowing a reciprocating arm to fall into the machine and shear-off an aluminum guide bar. Fortunately, the Smyth Machine Company is still in business, and they still use the same part on their modern machines! I ordered a replacement, and it arrived last week.

I was successful in sewing signatures together with the machine using six needles and six threads. The machine uses a combination of punches that come up through the spine of each signature, a needle with fresh thread in it, and a crochet hook that grabs the thread after it goes through the spine of the signature, turns it 90 degrees, and pulls it back up through an adjacent punched hole in the signature. From there that thread gets hooked by the next stitch, and that combination of actions makes a chain stitch that holds the book together for binding.

Despite the broken part, I was able to make a complete book block, ready for subsequent operations to make a finished case-bound (often called a “Smyth-sewn”) book.

Project completed!

You can read the related stories about the restoration of the machine here.

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Ink-jet trompe l’oeil buildings

I spent the last year in Europe, mostly in Munich, and I had a wonderful opportunity to visit several countries as a tourist before returning to the USA.

My wife and I became vagabonds after my final semester teaching at Hochschule München. We traveled mostly by train, and we stayed in hotels and rented vacation apartments. In each city we visited, we learned the local transit system and took buses, metro trains and trams to get around. We walked a lot.

In August, we took a short airplane flight from Amsterdam to Bergen, Norway. When we landed in Bergen we were pleasantly surprised by the sign at the airport there that has a curious punctuation mark on the end.

Oh my god! I’m in BERGEN? (Perhaps I thought I was in Buenos Aires?)

Is this because the Norwegians are not sure you’re in Bergen, or is it that the you are not sure if you are in Bergen? In any event, I have never seen a sign like this at any airport in the world.

Public transportation from the airport in Bergen to the downtown is inexpensive and quick. We dragged our luggage onto the tram and headed into town. (I became very fond of the Yiddish word “schlep” on this journey, as it is much more descriptive of my attitude toward baggage.)

Once in our hotel, we began a four-day stay with all the tourist trappings: the fjord tour, the funicular (and a hike back down), the cable car, etc. Since we were in the heart of the harbor area, we had a view of the old town, where historic buildings are lined up along the waterfront. This area is a UNESCO World Heritage Site, and is deserving of its title. (They also deserve a UNESCO World Heritage Cinnamon Roll Site title!)

Two of the buildings along Bryggen in Bergen are wrapped in ink-jet printed fabric.

The street called Bryggen faces south along the docks and features a line of small businesses that were once boarding houses. They are Bergen’s most charming structures. I took a photo from a boat as we left the harbor. The next day, while walking along Bryggen, I noticed that several of the buildings are in fact ink-jet printed façades that look like antique buildings. These cover scaffolding and construction – a clever way to maintain the World Heritage of the street while the buildings are undergoing renovations.

The buildings are printed on a sturdy fabric, meant not only to look pleasant from the outside, but strong enough to deflect falling debris, protecting the public from danger.

I have highlighted the two ink-jet building façades here. The one on the left is really obvious; the one on the right blends in nicely with its neighbors. Click to enlarge.

I have seen much larger printed scaffold coverings, one in Paris that was itself a trompe l’oeil work that looked like the original building underneath. It’s very clever stuff!

I assume that these huge coverings are printed on Vutek printers or similar machines. They are, on close examination, sewn to fit the façade of the structure. One of the coverings in Bergen was laced to the scaffolding to prevent it from wind damage and to keep it looking nice from the outside.

I wonder what happens to these coverings when the work is done. Are they discarded? Are they reused on other buildings? I would be curious to know if there is an aftermarket for printed scaffold coverings.

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Pushing the limits of repositioned panoramic photography (updated) (three times)

The Blognosticator in Munich

In several previous articles I have written about the process of repositioned panoramic photography. It works best when there is no perspective – strictly two-dimensional subject matter.

With my experiences with street art (see the most recent article here), this works perfectly. Photographing flat art – and painted walls are pretty flat – is what works best with this technique.

Photographing three-dimensional subjects causes this technique to fail with near-certainty. I think the first time I tried this seriously was when I attempted to photograph a huge Heidelberg printing press by taking an image, then taking three steps to the right, then taking a photo, etc. The resulting image, after assembly, was a catastrophe.

This is easily explained: perspective does not exist on flat subjects, and real things like printing presses have dimensionality. They have depth, and at every point on the camera plane that perspective is different. There is simply no way for software to reason-away differences in perspective.

This is my repositioned panoramic photo of a street and canal in Burano, Italy. The full resolution file is over 52,000 pixels in width and can be printed about 5 meters (15 feet) in length at 300 ppi. Click on this image to enlarge is to about 2x size. You may be able to click on that image to enlarge it more (depending on your browser).

Tempting fate, on a recent visit to Burano, Italy, I did it again. This time, instead of a 20-meter long printing press, I took a series of repositioned photos of an entire city block along a canal in that charming town, and attempted to put them together into a single repositioned panoramic photo.

I worked, kinda sorta. Well, not very well really.

But, enough of it worked that I persisted, and I was eventually successful in making a single image of the entire block, and it is charming. In the process, I took some liberties with the sides of buildings, the bows of small boats, and the waterway that separated me from the subject matter.

I took a total of 27 photos, each about 10 careful paces apart (I was not carrying my ball of string or my tape measure). The overlap between them was significant, but so was the perspective variance and the distortion of the wide angle lens (Canon 16-35 f2.8 at 21mm).

This is one of the 27 contributing photos of the Burano photo. Notice the television antennas on the roof of every building. These were challenging to keep in my master sky mask, but I managed to keep almost all of them.

To stitch them in Adobe Photoshop – which does a spectacular job on repositioned photos taken of two-dimensional subjects – I first had to take some of the distortion out using Photoshop’s Perspective controls. I put a baseline guide in, then two vertical guides, and I used an Action to perform the same perspective change on each image, straightening its vertical lines – mostly.

This is my screen in Adobe Photoshop after running my Action that placed guides on the photo, then applied Perspective to the image to compensate for some distortion from the 21mm lens.

After that I used Photoshop’s Automate>Photomerge function, with its Reposition option to put these images together. It didn’t do very well at all. I tried several times with subsets of the images, and was eventually able to create two big chunks of the repositioned photo that I then assembled into one using drag-and-drop. This final image was OK as a starting place, but there were fractional boats in the canal, and mooring posts that disappeared half-way to their pinnacles.

It looked pretty good, but it would take too much work to make it into a convincing photo.

So I gave up on Photomerge and decided to build this image by hand, assembling each image adjacent to the next by putting each onto its own layer, then creating a master mask to cut out the perspective parts that don’t work. This was complicated by slight differences in size and camera angle, so on each image I did some scaling and a bit of distortion to get the image to fit its neighbor to the left. Then I put the next image in, and did the same until I had completed the block-long photo.

Most of the buildings on the block are conjoined with their neighbors on both sides. There are only four alleys on the block where you can see into the distance to another building in back. So, with the exception of the rooftops, which have considerable depth, the façades of the buildings are two-dimensional.

I began my work by using the Magic Wand tool and selecting the sky, then making a drop-out mask with that selection on each image. After I had positioned all the images together I built a master sky mask by assembling all of the separate masks into a new channel mask. I replaced the original cloudy blue sky with a similar cloudy blue sky image.

This is the Master Sky Mask of my Burano photo. With this, and a replacement cloudy sky, I was able to make a pretty good looking composite image. I couldn’t use the original sky because it would not have fit my image with parts of buildings edited out. Click on this image to enlarge it.

The most difficult part of my master sky mask was television antennas. On top of almost every building there are skinny poles with various antennas attached. These didn’t select well with the Magic Wand, so I enhanced them with the paint brush on the sky mask, allowing them to be seen better against the sky.

I also had to remove parts of buildings in the background and visible from the street where I took my photos. This was done in the Master Sky Mask; I replaced these architectural artifacts with sky, and it is very convincing.

When the buildings and the sky finally made sense, I had to work on the boats in the canal. There is usually one boat per building in the photo – sometimes two – and each had reflections on the water of the canal toward the camera. Because of my intervals, the perspective of those boats, which are much closer to the camera than the buildings in the back, changed considerably from photo to photo. To remedy this, I took the best boat photo from each of the two overlapping images, and pasted it on top of the composite photo. This worked well, but I had to invent some of the reflections in the foreground.

When all was complete, I had my repositioned panoramic photo. At final resolution I can print this at about 5 meters long (about 15 feet) by 38 cm. tall (about 15 inches) at 300 ppi resolution. I don’t have any plans for the photo at present, but perhaps the city of Burano would like it for their City Hall. Or they could just walk outside and look at the real thing.

Addendum 3 September 2022

I’m in Norway this week, and will soon be returning to the United States after a year in Germany, teaching and experiencing the European lifestyle (excellent).

In Copenhagen there is a famous canal-waterway called Nyhavn, which features lovely old buildings, all painted different colors, and all built together along the waterfront. It is a mecca for tourists (me too!) because of its beauty.

I decided to try my repositioned panoramic photography there, using the same technique as described above. This time I used my iPhone 12 camera – normal lens (which is actually a moderately wide angle lens) – and I shot 17 photos along the opposite side of the canal. I did it with much more overlap this time, about 50 percent, and I took photos until I ran into a kiosk that prevented me from going any further (I would have liked to do the next block of buildings but there would have been a gap in the middle).

I opened all 17 images in Adobe Photoshop and used its Photomerge function to assemble the images into a repositioned panorama. This time it worked beautifully!

Except for the distortion of the left-hand sailboat, it is nearly perfect, and I have done no retouching on this image. I’m very happy with this one.

This is my repositioned panoramic image of the Nyhavn canal in Copenhagen. It can be printed at 300 ppi at about 1.5 meters in length. I will probably cut-and-paste the undistorted sailboat in the foreground before I do anything with the image. The most pleasant thing about this photo is that it required almost no extra steps to process. I opened the images and ran Adobe Photoshop’s Photomerge function.

Addendum to the addendum 14 September 2022

I liked the result of the photo above so much that I bought a Metro ticket and went back to Nyhavn another day (Copenhagen’s Metro is fabulous!).

This time I took my Canon EOS R camera and my only practical lens for this kind of work (16-35 zoom). Where I stepped three big steps between the shots on the photo above, using my iPhone 12 with the “normal” lens, this time I shot at 35mm, and I took only one big step between photos. I started at the left where the tourists board the sightseeing boats, and I took over 270 photos to reach the end of the canal where it meets the channel.

It took me about an hour. I didn’t use a tripod because I had shipped my tripods back to California. My only difficulties in getting a complete set of source photos were the obstacles on my side of the canal: tourists taking selfies and portraits of their friends and a few kiosks and signs that blocked my view. I shot until I bumped into a medium size ship moored on the south side of the canal. I had to stop then. I started again on the other side of the bridge there and shot images all the way to the end.

Just as I stopped at the bridge, the Queen of Norway went by in her limousine, with her motorcycle escorts and entourage! It was exciting. I had never seen a queen before.

The next morning I boarded a United Airlines airliner for my return flight to California, arriving the same day, but 11 hours en route. Now I am back in my home, putting the pieces back together after a year abroad. Among those pieces is my desktop computer, which sat idle during my absence. I put the hard drives back on the desk and plugged them in, and started it up. It works! (My RAID software tells me that I have one failing disk drive; I will replace that later today with a new one.)

This morning I made another attempt at Nyhavn, using 127 of the photos I took last week along the canal. I used Photohop, again, and its Photomerge function to stitch them together. And it worked admirably. I had to paste one of the boats into the canal on the left, and a part of one of the buildings was oddly distorted, so I pasted that part in from one of the source images.

It turned out nicely. This one can be printed about 8 feet in length at 300 ppi, and it has about 500 MB of size. I might try printing one very large to see how it fares.

Here is a reduced size image from my attempt today:

This is my second attempt to photograph the Nyhavn canal and stitch it together into one photograph. I made this image with 127 original images from my Canon EOS R camera. This is only half the canal; the other half lies to the right of this image. I have the source photos to put the other half together, but I have not attempted that yet. You can click on this image to enlarge it a bit.

Addendum to the addendum to the addendum:
Back in the USA after a year in Germany

We returned from our year-long adventure in early September. We immediately went to our storage locker, where all of our personal stuff was sequestered, and brought it all back home. It was kind of like moving. It was exactly like moving.

Then we reset our phones and changed our calendar preferences and tried doggedly to remember the passwords for the computers and bank accounts and other software and hardware that had been idle for 12 months.

And, after a few weeks resetting and cleaning and getting everything back in the closets, I decided to print the Copenhagen photo on my Epson wide-format printer. I had postponed this as long as I could because I knew it would be difficult to rouse the machine from its deep sleep. In 2017, after only five months in Germany, it took me most of a day to get all the ink-jet heads working again. I ran the test page and the nozzle diagnostic about two dozen times, and eventually it was working. I expected no less this time (I expected total failure this time).

I started up the Mac that runs my Epson, and I couldn’t remember the password for the machine. Nothing. Nada. Rien. Kein Passwort! I tried everything under to sun and failed. Then I tried screen sharing, and it also expected a password, but in this case it presented a hint: “Printer” so I typed “Epson” and the machine woke up. What a relief!

(I would never have guessed “Epson” as a password, and I never bothered to enter that password into my 1Password application to keep track for me. I was lucky to have had the hint.)

After a version update to Adobe Photoshop, I launched the program and opened the Nyhavn pano, chose my Mirage RIP software to print it, and amazingly, it printed flawlessly. No missing nozzles, no clogs, no problems! Hurrah!

I am very happy with the print. It’s glorious. The colors are gorgeous, the detail is amazing, and the method I used for repositioned panoramic photos was a success. I am sure I’ll do this again.

I am also very happy with my Epson printer and its uncanny ability to sit idle for a year and then start up with no clogged nozzles and not a moment of hesitation. Bravo, Epson!

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The Gegendruck

The Blognosticator in Munich

In our industry we throw around lots of arcane terms – offset, litho, ink-jet, gravure, roto, screen printing, make-ready, prepress, flexo, etc., etc.

I’ve been doing my best recently to learn similar terms in German, some of which don’t have an exact counterpart in English. One of my recently captured words is “Gegendruck.” Gegendruck means “back pressure” in English.

This is the steel printing die for my colleague’s business card. The lettering is cut with a CNC milling machine into a 12mm thick block of steel. Then a master engraver cleans-up the corners of some letters with a hand engraving tool. The image goes about 0.05 mm. into the steel.

Though it is close, it’s not an adequate English translation. The closest I can come is “counter” or perhaps “counter-die” – which is not really accurate because the term describes a thick card that is used to push against the back of the paper on a steel-die engraving press.

Counter-dies are common in foil stamping and embossing. They are three-dimensional bases that push the paper into a metal die that is either stamping or embossing that paper.

The Gegendruck is made on the press by making one impression of the steel intaglio die onto a thick card base (about 10 mm thick). These Gegendrucken do not have detailed relief except that they push against the image areas of the printing plate. They cover areas of the impression, not the lettering or the image.

Here, “Ronny” Kaevski, the steel die press operator, cuts the Gegendruck for one of the cards.

After printing on the Gegendruck, using an X-Acto knife, you cut away the non-image area of the card, leaving blocks that support the text or image being printed. Those areas are flat. In the plant where I learned how to do this (I made one myself), the press operator also adds tiny bits of sticky paper to accent marks, and to periods and commas that might be slighted by the impression on the press if not enhanced.

Once the Gegendruck is finished, it is secured to the underside of the impression area. Above it is the tympan (this term describes it generally) and above that is the frisket, a mask that covers the parts of the sheet not being printed by the die.

This is a close-up of the finished Gegendruck. Notice that the areas left high are the areas with type. Tiny pieces of sticky paper enhance the impression on punctuation marks and accents to prevent them from printing poorly.

I have seen many intaglio presses over the years, some of them roll-fed (roto-gravure) and some of them sheet-fed (intaglio or steel-die engraved). Until a few weeks ago I had never seen a hand-fed steel-die press, nor had a chance to see one working.

This type of printing is reserved for classy business and personal stationery, for fancy invitations and social printing, and security printing on a small scale. Currency is printed on the same technology, but on much larger machines that are machine-fed.

On this occasion, I was having business cards printed for my colleagues at Hochschule München. The cards, which we printed on Gmund Soft White 300 gsm paper were printed in two colors: the black lettering printed on the steel-die machine (called “Stahlstich” in German) and the red university logo printed by letterpress on a Heidelberg Windmill press (called a “Tiegel” in German).

The printing company, on the outskirts of Munich, is called Martin Schall GMBH. The firm specializes in security printing and specialty steel-die engraved printing, foil-stamping (“Prägedruck” in German) and extraordinary combination foil-stamping with embossing. Their presses include two 53 cm. Heidelberg offset presses, three large 100 cm. Heidelberg cylinder letterpresses with foil-stamping modifications, one Heidelberg 74 cm. cylinder press with foil stamping modifications. The firm also has two Heidelberg Tiegel machines for foil stamping and printing with ink.

The firm’s four steel-die presses were all built by Friedrick Heim & Co. in Offenbach, Germany in the 1960s. I can’t find any evidence that the company still exists.

Ronny mounts the steel die into the press. It hangs from the top of the machine, and passes the inking roller en route to the impression position. Then the impression plate rises up from below and transfers the ink from this plate to a sheet of paper with tons of pressure.

The making of steel dies for printing has always been an art practiced by master engravers who cut into soft steel plate with engraving tools (called “gravers”). It is a complex and painstaking process, with extraordinary results (look at currency for examples of this skill). Another technique is to make a photoengraving into steel or copper using photo-resist, a film negative, ultraviolet light and sulfuric or hydrochloric acid to etch the image into the steel plate.

At Schall, the company has a master engraver, Maximilian Schall, son of the founder, and an artist with extraordinary skill with a graver.

For commercial projects like mine, the company uses a CNC milling machine with precision carbide cutters. Digital files like those I created are converted to outlines in Adobe Illustrator, then cut into a steel plate about 0.5 in. thick. The depth of the engraved image is 0.05 mm (0.0127 in.). Because the machine is cutting with a rotating tool, all of the internal corners of the plate have round-corners. Max uses a hand graver to cut into the corners and sharpen those up to make them more faithful to the design.

Once the plate is machined, it is mounted in the Heim press and inked. The ink is American-made Cronite water-based ink for intaglio. The press floods the plate with ink, then a wiper removes the ink from the surface of the plate, leaving the ink only in the recessed areas of the engraving.

This photomicrograph shows the detail of the lettering in the steel die. The engraver has enhanced the corners of some letters to increase their sharpness.

Impression is several tons, pushing the plate onto the paper, and forcing the ink to transfer to the paper. This gives the printing that legitimate raised effect, where the ink stands out from the paper.

The Heim presses are hand-fed, and the operator uses one hand to lift a fresh sheet of paper, put it against the register guides and print. Then, using his other hand, he flips the paper around for a second impression on the same sheet. Finished sheets are laid out on a counter to the operator’s side.

The process is not very fast. Each impression takes about 10 seconds, limiting the output from these machines to 300 to 400 impressions per hour. After printing, the cards must dry overnight before going to the next process – printing by letterpress in my case, then the letterpress printing must dry overnight before the cards can be cut to size.

Overall, the quality of these cards is stunning. They are the classiest business cards in our university I am sure. We printed enough that it’s unlikely that any of the professors will run out in the coming years.

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