A tale of trailer wiring

Posted on August 13, 2023 by Brian Lawler

This is Part 3 of a multi-part story about making a trailer for carrying a generator to Burning Man. To read the previous episode, please click here.

The trailer is ready for licensing, so I have gathered the necessary paperwork, and I have my checkbook ready (what’s a checkbook?) and I am going to take the trailer to the Department of Motor Vehicles in the morning.

This is the unladen trailer, ready to go to the DMV. It’s not painted yet, but that will come later.

I picked it up from the welder’s shop on Friday afternoon and drove it to my house, which was a bit chaotic with house painters working at the same time. Nonetheless, I managed to push the trailer by hand into my driveway where I applied chocks to the wheels and began the process of getting the taillights wired.

For such a small and light trailer, it does not need brakes, so there is no need for wiring the more complicated electric brake systems that are found on heavier trailers. All I have is four lights: rear left and right running and signal lights and two amber marker lights on the sides. Hank, the world’s best welder, installed electrical conduits under the trailer inside of which I ran the wires.

California (I assume that all states have the same requirements) wants all trailers to have a lighted license plate, stop and turn signals, and the two marker lights on the sides. They also want to know how much I have spent building the trailer so that they can assess the license fee. I don’t yet know if this will be a permanent license (only needs to be registered once) or an annual license. I’ll find out in the morning.

To get the trailer to the DMV, they told me to drive it – even though it is not licensed yet. This small act of illegality amuses me. I drove it from Hank’s shop to my house, then once around the block to get it into a different parking place, and then I will drive it to the DMV, with the understanding that if I were to be questioned by law enforcement en route I can say, “They told me to do it!.” (That’s not going to happen.)

Wiring the lights was relatively easy. I bought a wiring kit from etrailer.com, and that came with a complete wiring harness, plugs, wires, clips, and several plastic three-way splicers. I fished the wires from the front of the trailer to the back through the conduits, then attached the chassis ground at the hitch, and worked my way toward the back. I wish I could tell you that it worked perfectly. I had a couple of problems.

This is the left taillight with its three wires coming out: white is chassis ground, yellow is left signal and brown is the common marker conductor.

The lights use only one conductor per color – yellow for left signal, green for right signal, and brown for all the markers. The second conductor is the steel of the trailer frame which carries the electricity for the ground of all the lights.

The two marker lights along the sides have only one wire coming out of them, and that wire attaches with one of the three-way plastic splicers. These things look effective, and I did try them. They allow the brown wire to slide through without cutting it, and the marker light wire (also brown) to enter through a parallel hole. Then, using a large plier, you push a small steel pin through the insulation of the wires and it makes electrical contact. Once that pin is pushed in fully, there is a plastic lock that folds over the top, keeping the pin in place.

This is the left side marker light.

I finished in a couple of hours, and was ready to test the system. I backed my VW Touareg into the driveway and put the hitch on the ball. Then I went to connect the plug and it wasn’t long enough to reach the outlet under the rear bumper of the car. Since I started at the tongue and worked backward there was no wire to pull forward to make it longer, so I had to make a splice to lengthen it (embarrassing!). While I was working on that I also decided not to have four loose wires going between the trailer and the car, so I used some waxed cotton string to make a wire loom by wrapping the string around and around the cable to hold the wires together and to cover up my embarrassing error. It turned out very nicely and looks great,

This is the clever three-way splicer device. You can see the steel blade in the center that, when pushed in, makes contact with both wires, connecting them. At least that’s the theory. They didn’t work, and I had to cut them out of the circuit and replace them with soldered joints with shrink tubing.

Hours later I was finished, again, and I plugged the cable to the VW and turned the lights on. Left blinker worked, right blinker worked. Brakes worked. Running lights and license plate light worked. But the two amber marker lights were both inoperative.

I stopped for the day to give my mind a rest and to attend a lovely choral performance in Mission San Luis Obispo. While I was showering to get ready for that concert I realized that it had to be the little plastic three-way connectors that had failed. Since both sides of the rear worked, the marker lights were simply not getting power.

Here is a schematic diagram of the complete wiring system. Click to see an enlarged view.

In the morning I tested this theory and determined that it was correct. I removed the splicers and cut the wires, then I put shrink-tube on each set of wires, twisted them tightly together and soldered them in place. Then I slid the shrink tube over the solder joints and heated those with a heat gun to shrink the tubing over the joints. After I cleaned up I tried the lights again and the two amber marker lights were both illuminated. This was what I expected.

With all the wiring complete I am now ready for the legal part of trailer-making. It should be no particular problem to get that done. I plan to be at the DMV when they open, trailer standing by. They will charge me money, give me a license plate, and a VIN number to apply to the trailer. I have no idea what form that VIN will take, but I’ll let you know in the next episode of this not-very-dramatic story of going from a drawing in Adobe Illustrator to a real trailer, ready to be pulled to Burning Man (just two weeks away now, and still a lot of work to do).

I will also show in the next story how I have built the electrical breaker box and power distribution box for the trailer. Those go on after it’s registered. Stay tuned!

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Trailering the generator

Posted on July 28, 2023 by Brian Lawler

I left my detailed plans for the generator trailer with my friend Hank Van Gaale, who is the best welder in the universe.

Then I flew to France, and went on to Switzerland and Germany for four weeks.

While I was gone, the trailer took shape. Hank welded the parts for the frame, attaching the spring brackets, the springs and axle, and then added a diamond-plate deck to the trailer. This piece was water-jet cut by my other expert friend Frank Canaan, proprietor of Central Coast Cutting. Water-jet cutting is one of the most amazing technologies I have ever seen. I wrote about it in a previous posting about the restoration of an antique typographer’s table saw.

This is the trailer with the generator, fuel tank and tongue box placed on it in their approximate positions. These will later be bolted to the trailer.

Frank’s amazing machine cut the diamond-plate steel with incredible precision, leaving holes for D-rings and bolt holes. That was then welded to the frame of the trailer. The hitch was welded on, the fenders added, and now the trailer looks a lot like it will when finished. What remains are the side railings, the front wall, and electrical conduits for the lights.

Ultimately what we are making is a portable electrical power plant. On the front of this machine will be an electrical distribution panel and breaker box. From there, up to eight power cords can be plugged in to provide electricity to our Burning Man camp’s refrigerator and freezer, several air conditioners, and the darkroom lights. We will also be able to provide power for our photo gallery.

The generator, which is a military surplus 5 KW diesel machine, can deliver electricity in three forms: 110 volt AC, split-phase 110/240 volt AC, or 208 volt three-phase. I have chosen to run it as a split-phase device, delivering two 110 volt primary lines to the breaker box. There, I will split the power to four 15-amp breakers, then feed the output to four ground-fault interrupter receptacles for powering the appliances in camp.

Running power of this kind requires some big wire, #2 gauge, from the output of the generator to the breaker box. I’ll be running these wires through two steel conduits that run under the trailer from back to front. At the breaker box the wires arrive as if from an electric utility.

From there, the power is distributed as if in a commercial building.

This is the electrical distribution system: a 6-breaker Square-D electrical panel, and a waterproof distribution box with four GFCI electrical outlets inside. The power comes in from the generator at bottom, then to the breaker panel, and eventually to the distribution panel on the left. Click for an enlarged view.

The trailer is stout – adequate to hold the 800 lb. generator and a 50-gallon fuel tank which, when full, weighs another 400 lbs. Add to that the electrical equipment and the spare tire and a tool box filled with filters and supplies, and the trailer weighs-in at just under 3,000 lbs. With any trailer it’s a combination of the overall load and the weight of the tongue of the trailer. We’re trying to keep that weight down so it doesn’t overload the vehicle that pulls it. This is done by moving the center of gravity forward or backward by moving the load or moving the axle. We have reduced the tongue weight to a reasonable value now, and the trailer’s load will be secured in these positions.

In order to drive with this trailer, I first have to register it with the California Department of Motor Vehicles. The way that is done is to take the finished trailer to the local office, showing them that it’s correctly built, and that it has stop lights and turn signal lights and marker lights. They check it for safety, then they issue a VIN to the trailer and give me a license plate to affix, and I can hit the road. For that to happen I have to wire the trailer, then get it through registration, then unwire it to get it powder coated.

For the electrical connections, I bought the breaker box and the distribution box on eBay, and I bought the wiring and parts from the local big box store. Now it’s just a function of doing the wiring. This is just like commercial wiring, where all wires are contained in steel conduit (residential wiring does not require the conduit). It’s easy and reasonably fast work to get four outlets wired to the breakers in the box. I did buy exterior boxes for this project, those being able to get wet without water getting inside the boxes. I connected the two boxes with a watertight steel nipple, so the wiring goes between the boxes without risk of water incursion.

I’ll follow-up when I’m ready to get the trailer licensed and powder-coated.

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Designing and building a trailer for Burning Man

Posted on June 24, 2023 by Brian Lawler

I will be attending Burning Man again this year, my fifth. The event was canceled in 2020 and 2021, and I was in Germany in 2022, so I have missed three years. I will be going out onto the Black Rock City lake bed again this August to join my compatriots for a week of art, unbearably hot weather and blinding dust storms. What fun!

I have written about Burning Man before, mostly about cameras, photography and dust. You can read those articles here and here and here.

This was the Man – a sculpture, a building, an art piece, at Burning Man 2019. The Man is burned on Saturday night each year with 75,000 people standing in a circle around it, enjoying the spectacle. Note the shadowy people in the photo. Typical exposures are from one to three minutes, so anyone not standing still long enough is not recorded completely. Photo by the Pinhole Project team 2019.

I belong to a Burning Man camp – The Pinhole Project. I joined that camp in 2018. Our purpose is to document, using huge pinhole cameras, the artworks that are installed on the Playa at Burning Man. These are the works made by people from all over the world and brought to Burning Man as expressions of ideas as diverse as the population of the event.

As you probably know, Burning Man is a gathering (not a music festival, not a happening – not a lot of things) in the desert of western Nevada. The location is a huge dry lake bed about 100 miles northeast of Reno. Annual attendance is about 80,000. That’s a lot of people – about twice the population of the city where I live. The theme of the event changes annually, but the principles remain constant: radical self-reliance. It is an opportunity for people to gather and express themselves in all ways imaginable. At Burning Man, nothing is for sale (except coffee drinks and ice) – it is a gift economy where everything is freely given. It is also an opportunity for artists to express themselves on a canvas of immeasurable size.

The photos we take with our large pinhole cameras are made on 30 x 40 inch photographic paper. After development, they are both negative and backward. To invert them, we photograph them with a digital camera and invert in Photoshop. At Burning Man we show people how triple-clicking on the power button of an iPhone causes the image from its camera to be inverted, making it positive.
This is the same photo inverted and flipped horizontally so that it represents the original scene correctly.

Called Black Rock City, Burning Man occupies a section of the dry lake bed about 10 miles square. There is nothing there before the event, and there is nothing there after the event. People come with tents or camper vans. Some take the bus, some bring cars, some come in private jets (there is an airport). Everyone camps on the Playa, which is set up in a circular pattern with concentric rings and spokes. The rings are alphabetical, the spokes are according to the hands on a clock. Camping is in a hemisphere between 2:00 and 10:00; the concentric rings begin about half-way from the center of the circle.

In the very center is the Man. This is a huge sculpture/structure made mostly of wood that is erected in the center of the site. On Saturday night it is burned, which is where the event gets its name.

The upper and center part of the lake bed, where there is no camping, is called The Playa. It is the location of over 100 works of art, each of which is built by a different group, and erected on the site in the days (sometimes weeks) before the event. Some of these works are huge – multistory buildings, huge sculptures, castles, stacks of wrecked cars – and sometimes they are small. In 2019 there was the Little Chapel of Thoughts and Prayers, a small church-like building made entirely of bullets, shells and gun parts. It was built of irony.

Our camp, as Burning Man group encampments are called, has a large space allocated to it. This year we will be at 2:30 and B (I think). In that camp we put all of our tents, yurts, RVs, cars and our cooking/pantry trailer. Each year we also have a 20-foot container delivered (this is stored in the desert year-round and is delivered by the Burning Man organization each year).

In this container is our darkroom, because the art we make is wet chemical silver nitrate photography. We use 45-gallon hardboard drums, inside of which we mount 30 x 40 inch photographic paper, held in place with magnets. On the opposite side of the paper is an aperture, a microscopically small (0.24mm) laser-cut hole in a sheet of titanium or aluminum. This aperture is the entrance point for light to expose the photo paper. The shutter is a magnetic sheet attached on the outside of the drum.

Art installations on the Playa include visitation by illegal immigrants. These Martians were there to see how normal human beings behave.

We take eight of these photographic drums – pinhole cameras – out onto the Playa each morning, and again each afternoon, to photograph the amazing artworks that have been erected there. When finished, we return to our camp and take the cameras into our container darkroom where the large sheets of photo paper are processed in large trays of photo chemicals.

The darkroom has an air conditioner inside. It often exceeds 100 degrees Fahrenheit at Black Rock City, so we really need it. And, we have a community cooking area with a refrigerator and a freezer, both of which are standard 110 volt appliances. In past years we have had rental generators that run on gasoline to power our electrical needs. Those generators were too small and they tended to fail often. We were looking for something more capable this year.

One of my camp partners found one on Craigslist. It was advertised as a U.S. military surplus diesel generator, designed for field deployment. It weighs 800 lbs. and generates 5000 watts of continuous power. It can run uninterrupted for days.

This is the MEP 802a military generator. Weighing in at just over 800 lbs., it was challenging to load and transport to my house from eastern California where I bought it.

I live the closest to the location of the seller so I agreed to go get it. I saddled up my Volkswagen Touareg and headed east… a long way east, to buy it and bring it back. En route I rented a U-Haul trailer and attached that to my car (I didn’t need to drag the trailer both ways). After several more hours on the road, I reached the destination where my new friend Cory showed me this behemoth device, started it up to show that it runs, and helped me to get it on my trailer (that required a winch).

After four hours more driving, I pulled up in front of my house then headed off to sleep. In the morning I delivered the generator to the shop of my friend Hank, who is the finest welder I have ever known. My plan is to have Hank build a trailer to carry this new generator so that we can get it to Burning Man, and then use it for the week to make the electricity we need for our camp.

This is my Adobe Illustrator drawing of the generator trailer, complete. When finished, it will have the generator, a 50-gallon fuel tank, and a power distribution system for four 15-amp circuits. The generator can selectively produce 110 volt single-phase, 110/220 volt split phase, or 208 volt three-phase power. It is powered by a Cummins two-cylinder diesel engine.

I have never designed a trailer before. I did my research and determined how long and how wide and how strong it needed to be. Then I found several online trailer parts suppliers (eTrailer is one). Over the following weeks I drew variations of the generator trailer, then perfected my drawings to give to Hank so that he can fabricate this work of vehicular art. All of the parts have now arrived and he will begin welding on Monday.

These are the plans for the Burning Man generator trailer. I over-engineered it to carry a heavy load and take a beating over years of use. I am confident that it will keep us powered up for numerous Burning Man events.

I started my work in Adobe Illustrator, drawing at a reduced scale. I added the generator, a large fuel tank, and a tongue box for tools and extras that we might need – filters, oil, coolant, a spare V-belt. I decided to add a spare tire and wheel, a spare hub and bearing set (can’t afford a break-down in the Nevada desert), and some tie-downs for things I might add to the trailer on its way to Burning Man.

I’ll write a few episodes in this adventure to show the process.

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Making Panoramas
and not getting lost in White Sands National Park

Posted on June 19, 2023 by Brian Lawler

My wife and I recently returned from a three-week adventure to Arizona and New Mexico. We stopped at a number of places en route, including Tucson, where I attended the annual summit of the North American Nature Photographers Association. It was a half-week event of photography and presentations at a fancy golf resort on the outskirts of the city. The hotel had a resident Great Horned Owl (and family), who would pose for photographers every day in his tall Pine tree next to the main building.

This is the Great Horned Owl at the La Paloma resort in Tucson, Arizona. It was an extra benefit for the many photographers who had gathered there for the annual Summit of the North American Nature Photographers Association.

The next stop was White Sands National Park in southern New Mexico, where we arrived midday and spent time in the gift shop before driving out onto the hard sand road that winds through the dunes. This is a remarkable place, as the sand is composed of gypsum, which is pure white, and very consistent in texture. The dunes range in size from little hillocks to moderate hills (the largest of them is about 60 feet tall, according to the brochure).

Midday in White Sands isn’t inspiring. The light is flat and uninteresting. We decided to go into town (Alamogordo, about 12 miles northeast) and find our campsite at Lee Oliver State Park, ten miles further to the east. We planned to return to the dunes at the end of the day when shadows are long and the light on the sand would be very dramatic.

White gypsum dunes as far as the eye can see! This is one of my late afternoon panoramas at White Sands. I used a Canon R5 camera and my 24-105mm Canon lens to capture 13 images. I stitched them later in PTGUI software, the best (only remaining?) professional panoramic photo stitching software. Click on the image to see an enlarged view.

White Sands closes its gates at night, and they warn you that you should plan to leave the park before dark. They are serious, as numerous visitors get lost each year, requiring search and rescue. It’s easy to see how easily people get lost in those sand dunes, because (to paraphrase Ronald Reagan) if you’ve seen one sand dune, you’ve seen them all.

This is, of course, not true. The dunes are incredibly beautiful and varied. Hiking on them exposes that variety.

But it is important when you go out onto the dunes that you know how to get back. Getting disoriented while hiking on these dunes would be very easy.

To plot our return, I called on my Boy Scout training. I found a unique mountain in the distance (I dubbed it Backward Half Dome), one that could be seen from anywhere on the dunes, and took a photo of it with my iPhone. Then, using the compass app, I pointed my iPhone at that mountain and took a screen shot recording its compass heading from our starting location. When we set-off on foot to explore the dunes and to take photos, I was confident that I could easily find my way back.

This is my photo of Backward Half Dome. It creates the geographic point of reference for getting back to the car.
This is the screen shot of the compass bearing of Backward Half Dome. With this information, I could easily return to our starting point by hiking in the opposite direction. Note that the Compass app also recorded the longitude, latitude and altitude. With these coordinates and a map, one could relatively easily find the way back.

The process is simple: find the mountain, point the compass at the mountain and move left or right until it’s at roughly the same reading as the original, then walk in the opposite direction. You can do this casually by just walking away from that mountain, or you can add or subtract 180 degrees to/from the original heading, then follow your compass at that new heading. This would use battery power on the phone, but checking it occasionally is effective.

In our case, the return was made much easier by a group of people who parked in the same lot we used, then climbed up to the top of the dune adjacent to that parking area to watch the sunset. We just walked toward those people (one of them was wearing a bright yellow dress, making it much easier to see her). We found our way back easily.

The shadows were as long as I had hoped, giving breathtaking dimension to the dunes, and providing me with a host of amazing scenes. I took a number of panoramic photos, most of which have Backward Half Dome in them. Sunset at White Sands is an extraordinary event, filled with visual surprises. It was a joy to be out there as the day ended.

Long shadows? You bet!

Follow-up thoughts:

While I was taking the photo of Backward Half Dome, I also captured a screen shot of an app I have called My Altitude. That is a slightly more accurate GPS-based application for hikers and bikers and kayakers. It makes reasonably accurate measurements of longitude and latitude (and altitude, though not as accurately). With a precise Longitude/latitude capture, one could enter those coordinates into Google Maps or Apple Maps and place a pin. Then use the mapping app to follow a route to the pin.

This is the screen capture from My Altitude, an app for iPhone that is often more accurate than the Compass app. It can be used when there is no cellular coverage, and in airplanes and hot-air balloons. I like its greater precision.

There was scant cellular coverage at White Sands. Without cellular, the mapping approach wouldn’t be possible, but with the My Altitude, I can capture longitude and latitude positions without cellular, so I could use that app to navigate back to a location, though it would be more difficult.

I am also a fan of the Strava application. I often use this while kayaking. It plots the course you have taken, and makes an overlay of your path on a map. With Strava, one could track outbound and follow that track on the return. The only hitch with Strava is that it processes the route offline (requires cellular or WiFi) and presents it to you later – sometimes much later. Like My Altitude, Strava does not require cellular coverage while you are moving. It gathers GPS data that is later collated with map data to create its nice experience maps.

This is a Strava map I made in March when my friend D.K. Philbin and I kayaked down part of the Colorado River from Hoover Dam to Willow Beach. These make great digital records of my kayaking adventures.

(My only gripe with Strava is their relentless effort to sell you stuff. They want an annual fee for the full-featured app, and they pepper almost every page with advertisements.)

The advantage of using the compass method is that one can just as easily use a mechanical compass (I have one!) and remove the iPhone from the equation. Then the only challenge is to remember the mountain you chose as your distant benchmark point. Using this more primitive technique requires no batteries. That could save your life.

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Adirondack chairs – delivered!

Posted on June 7, 2023 by Brian Lawler

You can read the previous chapter of this story here.

Late last year I decided to make a couple of Adirondack chairs for our upstairs balcony. These were designed to replace two chairs that we bought at a garden store. Those chairs, while quite nice, succumbed to the elements and finally fell apart.

I was determined to replace them with similar chairs made of a beautiful natural wood. After some deliberation, I chose Monterey Cypress custom milled at Pacific Coast Lumber in Paso Robles. The wood was cut for me, then kiln-dried for a month, and I took delivery in April.

Here are the new Adirondack chairs on the upstairs balcony of our home. It is a gloomy day, but they still look nice. It only took about six months to make them. The finish is Varathane water-based acrylic varnish. I love the effect is has on the Cypress, bringing out the honey color in the wood.

I took the lumber to my shop where I let it acclimatize for a couple of weeks before planing it and finish-sanding it to two thicknesses for the chairs: 3/4 inch and 5/8 inch. The thicker boards are for the load-bearing parts while the thinner boards are for the seat boards and staves.

This wood came from a tree that fell in Morro Bay State Park during a storm. I like that provenance, as I have obtained other locally-milled lumber from nearby Cambria and from a tree that fell on a highway east my city. There would be a story here: storm-damaged tree converted to elegant outdoor furniture.

Working with this lumber was more difficult than the romantic picture that I had painted. From the moment I began planing, the lumber’s internal demons began to escape, causing long (and sometimes loud) cracks to appear. While resting one day during the sanding operation I heard a loud crack come from my stack of 5/8 inch lumber. This would not be the last such crack.

This is the process of gluing the neck board to the vertical staves, the very last piece to be added to the chairs. I have a motto that says you can never have too many clamps! Variety counts, too. Here I am using four large Jorgensen clamps and five Rockwell narrow clamps to hold the staves to the board while the glue dried. For anything like this I use Gorilla Glue, because it is the only truly waterproof glue that I know.
The neck board was surprisingly difficult to make and attach. I cut it on the CNC machine then fit it by sanding it on the spindle sander. Then I broke three of them, and made them over and over until I finally succeeded.

I cut all the pieces (covered in previous episodes of this story), and then reduced them to final size both on my table saw and on the CNC machine where necessary. I did some manual cutting on my band saw (where a curve also had a sharp internal angle). Then I followed that with a lot of hand sanding and preparation for assembly.

Almost every day when I was working on this project I was faced with another debilitating crack. These would open up in boards as I screwed them to the frame, or they would open up overnight while glue was drying. This week I had a problem with the final board not fitting the vertical staves correctly. I changed my design, then made a new piece on the CNC machine, and while sanding it, I dropped it to the floor. It shattered.

So I made another one and tried again. That one cracked and broke in half while being clamped in place. So I made yet another one that I was successful in mounting to the back of the chair.

While doing my final sanding, I noticed that a crack had opened up on one of the vertical legs of one chair. Since this is structurally critical, I disassembled the arm and brace, and glued-up the crack with Gorilla Glue (waterproof). I let it dry overnight, then sanded it and reassembled the arm to continue my work.

When I finally finished sanding the chairs, making them ready for a spray coating of clear acrylic, I stood back to admire my work. CRACK! I heard it, but I can’t find it, so I decided to move ahead and get the first coat of acrylic on the chairs. Perhaps the acrylic coating will hold the wood together!

The chairs have a wonderful color when coated. I call it light honey. I completed the first coat yesterday, and the second coat today. After a day to dry, I will do a light sanding and put another very light coat on top, finishing (?) the project. Then I will deliver the chairs from the shop to the house and my wife and I can sit on them in the evening as the sun sets over Cerro San Luis Obispo.

The epitaph:

Would I do it again? Absolutely. I will almost certainly make more Adirondack chairs. These are my sixth and seventh, and I really like the design.

Would I use Monterey Cypress again? No. I think it’s lovely wood, and I am sorry that my relationship with it has been so troubled. I think it’s too brittle for this kind of project. I am very happy with the overall appearance of the chairs. They are very nice. But I fear that the cracking is not over… I have recurring dreams about sitting in my chair on the balcony and having a crack streak up one of the rear staves.

Also, this wood was quite expensive compared to other woods available at my local hardwood store. I could probably have made these chairs out of Hard Rock Maple and spent less money on the raw lumber (and it would have cracked less).

What wood should I use next time? In my Adirondack chair adventures I have used Monterey Pine, Baltic plywood (a prototype), red Oak, and now Monterey Cypress. I might try Birch on my next chair, or perhaps Poplar (I have read mixed reviews about Poplar). Birch is hard to get right now, but I can probably find some.

Would I build them the same way? Yes, but I will make small changes to the design to get the vertical staves to fit better. That would make them easier to assemble and complete.

Would I spend the better part of six months building them? Who knows?

Meanwhile, I have started a new project! It’s a custom utility trailer that will carry a military surplus 5KW generator to Burning Man. It’s my first trailer, and it will be made entirely of steel. Since I am not a welder, I’m having the best welder I know make the trailer for me. It involves fabrication, assembly, powder-coating, licensing, testing and ultimately the installation of high voltage electrical circuits to provide power to the Pinhole Project camp at Burning Man 2023.

More on this as it is built.

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Chair-man of the board

Posted on April 26, 2023 by Brian Lawler

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 you can read here.

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A new Adirondack chair for 2023

Posted on March 4, 2023 by Brian Lawler

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

Posted on February 16, 2023 by Brian Lawler

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

Posted on February 15, 2023 by Brian Lawler

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

Posted on February 2, 2023 by Brian Lawler

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!

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