You Don't Have To Do This To Impress Me

I often show the Tormach making the parts, but there's more to the process. I design the part in 3D, then I write a program to carve the part out of stock material. I then have to mill stock material down so that it's the same dimensions or slightly smaller then the carving program expects. I have to precisely set the X, Y and Z axes and measure the heights on all the cutting tools used. After all that, I can finally run the program that makes the part. These are all the steps I take when I say the part was "straightforward" to make.

The two lever-assist arms were straightforward to make. After setup, I was able to make both of them in one afternoon. That's the best feature of the CNC mill. I can make the same part over and over, but I usually only have to do the setup once.

The Final Four

Previously, I described the suspension as a seesaw. The wheel is attached to one end of the seesaw and the other end is pinned to the central frame. A lever arm rotating around a fulcrum moves the seesaw, pushing the wheels into the ground and lifting the front end. The last four parts to be made were the two lever arms and the two fulcrum brackets.

The original design of the lever arm was pretty basic (shown above). Before I actually made these parts, I redesigned the interior of the arms to look a little more Star Warsy. I always say that, to me, the engineering is the art and this was a great example. Each arm took most of a day to run, and they came out really cool!

The fulcrum bracket is the physical connection between the chassis and the point in space where the fulcrum is located. The lever arms attach to and rotate around the fulcrum bracket. I designed a simple bracket oriented at an exotic angle. Two long tubes connected to the chassis and also to each other. Because the tube intersections created complex profiles and because the placement and shape of those profiles had to be fairly precise, I used the Tormach to make them before I began carving out the lever arms .

I also made the cross-pieces for the fulcrum brackets–the attachment plates and pivot tubes–on the lathe at the same time. Once the pieces were made, I set about welding them into brackets while the Tormach worked on the lever arms.

First, I clamped up and welded the attachment plates and pivot tubes onto the ends of the long tubes. Those connections were perpendicular, so I only needed one clamp to hold them together.

Once the pieces were welded onto the long tubes, I then had to arrange and hold the long tubes at the correct angle. Getting them positioned correctly took some effort. I did have a short truss that was the same shape as the Falcon's truss. I was able to use that as a jig to prepare the final joints.

After clamping the long tubes to the truss using hose clamps, I used angle gauges to set the 34 degree angle between them. I moved the two legs around until they were snug up against the gauges.

I spent a lot of time getting this angle right. If the fulcrum ended up in the wrong spot, it would make assembling everything much more difficult. I checked the position of the brackets relative to the chassis by putting a level on the chassis, then putting the level across the fulcrum tubes, and comparing the reading. Everything lined up.

I tack welded the last joint on each bracket to make sure they did not shift while I worked on them. Then, I began to weld. The TIG torch had sprung a leak and could not be used, so I had to use the MIG welder instead. MIG is an ax to the TIG's scalpel. TIG melts and you add metal in small drops. MIG adds metal as it melts. I had to be extra careful. I could easily add too much metal or worse, burn holes into the tubes.

The perfect TIG technique refers to "stacking dimes," or laying out the beads so they overlap each other. If you do it right, your welds look like a necklace. I have flashes of competency, but my TIG welds are usually very ugly. Since I had to use MIG, I decided to try to fake the dimes. As the machine fed out wire, I made small, circular, overlapping motions.