Oh Yeah? Watch This.

 

After fabricating most of the interior parts of the new suspension, I tackled the parts that make up the knuckles. 

What's a knuckle? The knuckle mainly holds the wheel in place but also allows the tire to rotate on three axes. Not only can the tire spin and turn, but the knuckle also allows the entire assembly to rotate when lifting the front end. Our knuckle is made up of a bearing plate, two knuckle brackets, and two pivot brackets.

We've had a version of a knuckle on the previous two designs. The new design has an extra degree of freedom. I also added a lip to the bearing plate to prevent the bearings from squeezing out--the issue that ended our last race. I rounded the back of the knuckle brackets so we could get ±45° of turn. I also thickened the bottom of the bracket to better accommodate a bearing.

The new bearing plates were done previously, so I began this push with the upgraded knuckle brackets. I manually machined aluminum stock to the dimensions I needed to carve the parts out on the Tormach.

Because these brackets are one of the smallest of the CNC'd parts, I was able to make four of them on the same day. Until now, most parts have taken a day each. After the main parts were done, I used the manual mill to add mounting holes needed to connect the knuckle brackets to the steering components.

The pivot bracket was another story. This bracket has to attach to and rotate around the suspension legs while also attaching to the other pivot bracket above it, and also support the knuckle brackets. In order to accomplish all this, I had to run setups on four sides of each aluminum block. Usually, only two sides are machined to make a part. The top side "Han in carbonite" setup carved out most of the parts' features. I had to use extra long end mills to reach all the surfaces.

I then moved on to the features on the sides: a through-hole larger than the 3/4-inch threaded rod going through it, and a "cup" for a bearing. The two sides, though, had to be aligned with each other. I used the newly machined top and back faces to set my origin for both sides. Because both surfaces were machined, I was fairly confident that the starting point for each side was the same. 

Both setups ran the same operations. First, the bearing cup was carved out. Then, the clearance hole was bored. I didn't have an end mill long enough to get all the way through the part, so I only went down halfway on the clearance hole. 

There were slight variations between the two sides, but it was small enough that a 3/4 inch threaded rod still fit all the way through the part. And that's all that we need. 😎

The last setup was for the bottom side of the part. Weight is always a concern, so I removed most of the extra material and left a cross pattern centered around the knuckle bracket mounting hole. The "T" cross-section will help minimize flexing of the bracket's "floor".

With the four knuckle brackets and the four pivot brackets completed, we are now 83% done with the build! Not far now.

The last six parts are on deck. These parts include the arms that actuate the scissor lift function and the brackets that the arms rotate around. There are aluminum and steel parts, and I'll need the Tormach for all of it. 

For the Glory! 

Rudy July 08, 2025

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Let's Just Figure Out a Way to Get Out of this Thing

Work on the Falcon's suspension system continues. I usually try to maximize my time when I'm in the shop. While the Tormach mass produces the more complex parts, I work on the parts that can't be made that way. This time I tackled the custom hangers.

The suspension system is basically a seesaw. The hangers hold one end of the seesaw at the correct position and provide the tension needed to hold everything together. They are made up of two bearing tubes and two spacer bars. 

I first tackled the eight bearing tubes. I cut steel tubing roughly to length on the bandsaw and turned the ends down to size–pretty easy to do on the lathe. I also widened the inside of the tubes slightly so the bearings would fit.

The spacer bars were harder. The distance between the bearing tubes had to be the same for all the hangers. I needed to make these on the Tormach, but there was one problem with that. The finished part was shorter than the vice holding it, so I couldn't mill both sides in a single setup without cutting into the vice. I'd have to do it in two setups.

In the first setup, I milled the desired profile into the free end of the bar and then milled a small hole on the other side. Why a small hole? Since I had to take the part out of the vice and turn it around to finish it, I needed a way to reorient the bar and set an origin for the second setup. The hole provided this function.

To set up the other side, I mounted a gauge pin on the Tormach like a drill bit. Then I slid the bar over the pin, auto-aligning it with the machine. I locked the bar into the vice and set the machine's X and Y axes to zero. Then the Tormach cut the second profile while also removing the registration hole and finishing the part. I repeated those steps seven more times.

Once I had all the pieces, I was ready to weld them into the final parts. I machined a gauge block to ensure the correct spacing between the bars, then clamped up each assembly and tack-welded all the hangers together.

I'm getting a little better at welding with all the practice. The thing I'm learning most is patience. Instead of trying to weld everything everywhere all at once, I welded a quarter of the way around on each bar. Then I let each hanger cool off before welding it again.

I still seemed to overheat the metal periodically, causing porosity when the molten metal hit dirty air. I had thought it was because of the air inside the tube, but I later discovered that the torch had sprung a leak. Not enough gas was flowing out of the torch to create the curtain of inert gas necessary to form strong welds, causing all the pock marks (porosity).

I eventually switched to the MIG welder to finish welding the parts, but that added the extra step of cleaning up the welds with a grinder.

The last step was to clean up the inside profiles of the bearing tubes. I had smoothed them out on the lathe when I made the bearing tubes, but welding always deforms the metal a little bit. I used the ever-versatile Tormach to re-contour the tubes.

With these four parts, the suspension system build is 61% complete!

Rudy June 30, 2025

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Leave Them To Me. I Will Deal With Them Myself.

Fabrication of the new suspension continues. I made the last of the hanger brackets, so we can now officially attach the new suspension to the Falcon!

I also made the next four parts in the build: the alignment bracket that keep the hangers and the suspension arms in the same position, relative to each other.

These were deceptively difficult to make. First, because of their size, I had to hold them in the machine differently than usual. That wasn't too bad. I just moved the jaw bolted to the front of the movable block on the vice, onto the rear position.

Carving out the first side of the part went well. I like to call this the "Han in carbonite" phase.   

I was able to remove all of the interior material without cutting through the bottom of the stock plate. The stock I used is 3/4 inches thick and the bracket is .7 inches thick. That 0.050 difference made sure I didn't accidentally cut into the vice. Because the vice jaws were in the way, I couldn't cut along the outside of the part. That left the bottom .25 inch thickness of material to avoid that.

I usually just flip the part over and remove the "carbonite" layer to finish the part, but since I need to maintain bracket thickness I also had to precisely trace the outline of the part from the other side. That's why there was one hole cut all the way through the first side. That hole became the origin for all the flip side operations.  

I began finishing the second side by manually cutting away most of the extra material using a bandsaw. It didn't take very long and helped reduce CNC machining time.

Because the part is triangular, I had originally planned to hold it along the hypotenuse but that wasn't possible. In that orientation, the part is not wide enough for the vice to hold it. And, yes, it was also too wide to move the vice jaws back. smh

I was stuck. To finish the part, I needed to make a custom jig–a part to finish the parts. If I could clamp the jig in the vice I could then secure the triangular brackets to the jig. I began with a 6 inch by 6 inch stock plate and designed the jig to use the central trapezoidal shape of the part to keep each bracket from shifting or rotating. I added 1/2" threads so I could lock each part down onto the jig with bolts.

Using bolts on the inside of the part meant that I couldn't use the Tormach to finish the back face of the bracket, so I did it manually. I had to keep the face mill moving to avoid tool marks. It reminded me a bit of playing the drums.

Once the jig was complete, I slipped each faced bracket on, bolted it down, and cleaned up the outlines.

The jig made easy work of finishing the alignment brackets.

With these parts, we are 50% through the build!

Next up, the parts that attach the wheel to the suspension and all the remaining steel structural pieces. For the glory! 

Rudy June 03, 2025

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It's Your Imagination, Kid

Over the last two weeks, I've made progress fabricating parts for the new front end suspension. Most of the thickest parts are done. Those take the longest to make on the Tormach. For example, each front bracket took 7 hours to machine from a solid block. 

After making the second front bracket, I checked its fit and discovered that the far side of the large hole was milled slightly smaller than the near side. This happened because I had to use an extra long end mill to reach everything. 

The free end of the tool flexes from the cutting force created. The longer the end mill, the more the end deflects. I had to slow down the travel speed considerably to minimize the forces acting on the end mill, but that did not remove the flex entirely. To fix it, I flipped the part over and widened the hole from the other side using a shorter end mill.

After the second front bracket was finished, I made one of two rear hanger brackets. It's shaped like a saddle instead of a circle so we can mount it further in on the truss.

The final test fit for the brackets was great. I haven't drilled mounting holes into the brackets yet. That will happen when we're ready to install the new front suspension.

We've Got Arms

While the Tormach sculpted away, I continued welding together the suspension arms that attach the wheels to the central truss. I used steel instead of aluminum for increased strength, but mostly because I had access to free steel and virgin aluminum is expensive. My welds are still ugly, but I think I've gotten 5% better. 😎 Out of 8 arms, I only destroyed, and had to remake, one arm. 

After welding the arms together, I re-machined the inside diameter of each tube to remove deformations caused during welding. This will make sure that bearings will fit into the legs.

With the two front brackets, one rear bracket, eight arms, and the two bearing plates fabricated, the front suspension build is over 33% complete. For the Glory!

 

Rudy May 21, 2025

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