No, no. This one goes there. That one goes there.

Truing a wheel refers to aligning the rim in relation to the hub by tightening the wheel's spokes. My first attempt was trash. There was a pronounced egg shape radially and the sides of the rim wobbled back and forth. I didn't have a truing stand and Lowell Makes' stand wasn't wide enough, so I tried to true it by eye. Like I said, trash. I started over. 

I loosened and/or replaced all the spoke nuts and watched more videos on lateral and radial alignment. John at The Bike Connector suggested that I mount the wheel on it's frame and use that as a truing stand. Brilliant! And something I should have realized myself. SMH

The videos were very informative. They used the adjustable indicator on the truing stand to find the high spots on the rim while it spun, mostly by ear. The rim made a slight scraping sound whenever it touched their indicator. 

I jerry-rigged an adjustable indicator by zip-tying a clamp to the truss frame.

This gave me adjustability without having to reposition the entire rig every time. It was much easier to find the misalignments and correct them. 

It still took 3 hours to get everything lined up. But now

🎵"This wheel is TRUE!"🎵

After getting the rim aligned, I put the tire back on the rim, attached the brake disc and drive sprocket, and mounted the rear wheel! The sculpture has been up on blocks for a long time. Finally, one of the wheels is on the bus!

The Front End

I re-mounted the differential using the new bushing plate/nose cone. 

I noticed that the new plate still flexes a little when mounting. I'll wait until road testing, but we may have to make a thicker plate. 

I modified the right side knuckle to reduce binding while turning and finished mounting both knuckles, including the Haim joints.

I also fabricated the steering plate and the pieces for the steering support. After our machine shop captain welded the support pieces together, I mounted the steering plate to the truss frame.

I made connectors for the tie rods that link the Haim joints on the knuckles with the steering plate. The connectors are joined using threaded rods.

The Front Wheels

I have been avoiding dealing with the front wheels. A solution for mounting the wheels on the CV axles had not revealed itself yet and there were many other "solvable" problems to address. But no longer.

The front wheel hubs came with 0.5" holes for standard bicycle axle bolts, but the CV joints that the wheels must attach to are 0.75" in diameter. 

First I tried to drill the holes wider, but I barely made a dent. I started getting worried as this was my big idea to make the wheels work. I consulted with our machine shop captain and he discovered that the ends of the front wheel hubs were not solid but cups that could be removed. Huzzah! 

Using a hammer and screwdriver we popped out the cups and now there's a 1.16" hole. And no drilling required (this time).

This helped us to finally work out how the CV axles will interface with the hubs. We designed sleeves to fit over the CV axle ends. The inside bore of the sleeves is significantly smaller than the CV diameter. 

To mount them, we will heat the sleeves up until the inside holes expand wide enough to slip over the CV axle. They will snug up into a very tight press-fit as they cool.

We also designed a custom shoulder bolt that screws onto the end of the CV axle, securing the bicycle hub to the axle. 

The hubs will slide over the sleeves and the bolts lock everything down. The bicycle hubs have a brake disc bolt pattern on their flanges. The brake disc attaches to these bolts, and a custom spacer helps align the disc.

CAM files were created for everything but the bolt and parts were made out of aluminum on the Tormach CNC mill. 

I originally expected to keep the hubs on the wheels to save a lot of time, but the rims are in the way of some drilling that is needed to finish the work. 

I took the hubs off of the front wheels to work without obstructions. But now that they are off, I decided to get new hubs.

The original hubs are front/rear, so they're two different sizes. They would require different parts in order to mount them. 

I ordered two identical front hubs instead, in the spirit of standardization. I'll check the fit of the inside diameters when they arrive. 

Hopefully, I can use the sleeves I already made. I won't need the brake disc spacer, since the new hubs already come with a flange for mounting brakes. I haven't made the CV bolts yet as I'm waiting to see if I have to make any adjustments.

The Hyperdrive

Meanwhile, I started assembling the Hyperdrive.

The axles are too short for some reason (It's me, hi. I'm the problem. It's me), so I ordered new ones. The short belts are a little too long, but I have enough adjustment in the hyperdrive to pick up that slack. Though, I may have to make a longer tensioner block to be able to use four screws. We'll see if that's actually a problem.

The long belt is also a little too long (but the next size down is way too short). I found a spot along the path of the long belt where I can add another idler pulley. 

That should take up the extra length. I have to wait a week to get that part, so I'm putting a pin in that.

I won't idle while I'm waiting. Time to tackle the seats and pedals!

Rudy July 31, 2023

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Watch Your Step. This Place Can Be A Little Rough.

 We are marching ever forward, though sometimes I feel like we're standing still. I've made a little bit of progress on a lot of things. First, the front and rear wheel supports have finally been mounted to the frame! 

Now we just need mountable wheels! 🤔 The front wheels are still a bit of a question mark, so I worked on the rear wheel. I tried rebuilding the 26" rear wheel to use a rear hub (the tire originally had a front hub). It wasn't too bad for my first time. I watched a video on building bicycle wheels a few times and referred to it while working.

Then an issue revealed itself. The video I watched was for a regular wheel, but we're using fat wheels on the Falcon. The spoke pattern is slightly different than a regular wheel. Suddenly, I was lost and the wheel was in pieces.

Luckily, I had two of these tires. The second wheel was a great guide for placing the spokes correctly into the rim. And I was able to finish installing the spokes. However, the original spokes turned out to be about 10mm too long for the new hub. 

I had measured and compared the original and new hubs and thought it would work, but I thought wrong. And so it goes with kinetic sculptures: expect modifications to the modifications. New, shorter spokes were ordered. And I rebuilt the wheel with the correctly sized spokes.

Now I have to true it. There is a truing stand in Lowell Makes' Bike Shop and videos on how to use it on YouTube. Once it is balanced, I will finally be ready to mount the rear wheel!! Yay!

Stiff Knuckles

I also addressed the problem of the stiff knuckles on the front, left side. The knuckles allow the wheels to change direction while allowing the wheel to spin. This is key to the front-wheel steering. I discovered during the first dry-fit that the front suspension had warped a bit during welding and the space where the knuckle sits shrank by .150". 

The knuckle brackets have ledges where the bearing plate attaches. At first, I thought I could mill those ledges down, but I realized that wouldn't work. Doing that would also require modifying the bearing plate. Too much work.

Instead, I lowered the counterbores on top of the brackets. I hesitated doing it this way initially, because I thought it would be harder. But it only took 5 minutes to make the change to the 3D model and another 5 minutes to run the update on the Tormach. Easy Pease.

The knuckle moves so well now that I'm going to do the same thing to the knuckle brackets on the right side. 

Hyperdrive Assembly

We made some strides on the Hyperdrive, the heart of the Falcon's drive train. 

I finished making the pulley frame and additional parts on the Tormach last week.

All the bearing cups were pressed into the frame and tensioner blocks. Our machine shop captain then welded the cups to the frames. 

After welding, I pressed the bearings into the tensioner blocks to confirm that the axles actually fit through the blocks. So far, so good.

I also drilled 1/2" holes into all the pulleys, so they can be mounted on the bearings. 

However, I realized while I was doing this that the pulleys do NOT have set screws. This means they cannot currently be locked to the axle. smh. I've been staring at these things for months--MONTHS--and still I missed it. Sigh. It's not world-ending. I just had to drill and tap holes in the pulleys for set screws. But it's another step that takes time.

I almost finished putting set screws into all the pulleys, but then I managed to break two taps in two minutes. And it broke low in the holes I was tapping, so they are sticking slightly into the axle hole. Now I have to drill out those holes to remove the offending tap material. Yet another step.

Differential Alignment

Also during the first dry-fit, I mounted the bushing plates I designed for the modified lawnmower differential. I eventually got it to spin freely, but I had to tune its alignment like a drum--turning nuts a bit at a time while checking the spin. The alignment was so sensitive that I know road conditions would definitely knock the differential out of tune.

I realized that all the bushings had to sit on a common surface. They would then stay aligned to each other without needing fine adjustment. This is actually how the original differential case works, so that should have been a clue. 

I then designed a single plate that attaches to the existing brackets and has mounting holes for all the bushing blocks. But it couldn't just be a plate with holes in it, right? It had to feel a little more Falcon than that.

Once I was happy with the new design, I used the Tormach to make it.

Because the shafts are longer than the mounting area, I had to first place the bushings on the shafts and then bolt the bushings to the plate. It works pretty well now. There's still a slight stiffness, but I think lubrication will correct that.

After this test fit, I had to take the differential off one more time, all because of Marisa Tomei.

My Cousin Vinny was on the other day. Marisa Tomei is giving her testimony that saves Vinny's cousin and it ended up saving me, too.

LOL, she's right. The Falcon has a regular differential. So, the Falcon's front tires will do the same thing as a '64 Buick Skylark. One wheel will spin while the other one does nothing. Well, we can't do a limited-slip differential, but we can do a locking differential. 

To make it spin like one solid axle (locking), I modified the design of the sprocket adapter plate (the plate bolted on the left side of the sprocket in the image above). I added another hub on that side then drilled and tapped holes for a set screw. 

Now when I want to turn the Falcon into a mud crawler, I just need to screw down the set screw and Viola! And it's all thanks to Marisa Tomei! 😁

Rudy July 17, 2023

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The Force Is Strong with [TORMACH]

There's a lot to make. And what needs to be made would take a really long time, if they had to be made manually. So I'm always looking for force multipliers that will make the jobs faster or easier, or both. In the Lowell Makes machine shop, that force multiplier is the Tormach!

Hyperdrive frame on the Tormach CNC mill

The Tormach CNC mill is a computer-controlled machine that carves parts from blocks of metal. To produce a part, I have to design and model the part in 3D. Then I create a CAM program to tell the Tormach how fast and deep to cut, what tooling to use, and what paths to take. All that takes hours before any IRL metal is cut.

The latest part I worked on is the frame for the main drive train of the Falcon, which I dubbed the Hyperdrive (haha). Here's the design.

Here are just two CAM operations that make the frame.

The frame is too wide for the Tormach's reach, so I had to create two setups that each worked on half of the frame. I had to move the plate over to do this and somehow keep the plate aligned. The short side of the frame was aligned using the back, stationary jaw on the Tormach but the long side still needed a common starting point between the two setups. The trick was to machine an edge into the first half of the frame as part of the first setup, then use that edge as the origin for the second setup.

Surface used as origin of second CAM setup

After many changes, our machine shop captain blessed my CAM programs. I got started making the real frame. I spent the first day just setting up the stock on the machine. 

First, I had to adjust my CAM setup until all the operations fit inside the Tormach's milling envelope. It can realistically mill inside a 14" x 6.5" area, but that also includes the diameter of the tool used, so effectively it's 13.7" x 6.2" using a 3/8" diameter tool.  It was easy to tell when it fit because the machine refused to continue if it didn't. Next, I had to mount the stock metal. This was the hardest part of the setup.

Because of the Tormach's dimensional constraints, I had to slim the design of the frame by almost an inch and reduced the size of the pulley mounting holes to reduce the length. The final frame dimensions became 5.5" wide x ~25.5" long. I also milled down the stock from 7" wide to just under 6 inches. It was quicker to do that on the manual mill. 

The last part of the setup was securing and supporting the stock material. The center of the milling area was secured by a vice on the machine, but metal stuck out from both ends. If I tried to machine it like that, the metal would start to vibrate whenever the tool danced over the ends. I needed to jack up the ends to increase the material's stiffness. 

Instead of ordering machinist jacks and waiting, I took our machine shop captain's advice and made jacks out of some spare aluminum blocks and a few bolts. Then I used those jacks to hold up the ends of the stock. 

All that was the first day. 

I then spent the next two days running the first CAM program, moving the stock, resetting the X origin, and running the second program. And cleaning. The sheer volume of aluminum flakes was enough to fill half of a 30 gallon trash bag. That takes a while to vacuum up.

The final result came out great! I had a few mishaps that removed some "extra" material from the surface of the frame, but nothing that would ruin the part. And now it has some character.

I would have never been able to do something this intricate manually. I could've made something, probably rectangular shaped, that worked but didn't look as good and probably weighed more. And I think it would have taken at least as long. Now, thanks to the Tormach, it's ART.

Oh, and multiplying my machining skills is not the only advantage of using the Tormach. Once a program is proofed (i.e., pretty sure you won't ruin the machine, the part, or your tool), I can do other things while a job is running. For example, I can prepare the stock for the next CAM job while the current one is running. But I'm always listening for the high-pitch whine of the tool happily cutting through material.

The frame was too complicated to leave unattended. But while I worked on the CAM program for the frame, I used the Tormach to make 14 bearing cups that will mount and weld to the frame and 4 tensioner blocks that will also mount to the frame and will allow me to tighten the belts around the pulleys. 

The bearing cups were a particular win. Making those on a lathe would have taken me days. With the Tormach, I was able to bang those out in 2 hours.

I now have all the pieces to put together the Hyperdrive, and it's thanks to the force of the Tormach!

Rudy July 06, 2023

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