Keeping things straight—welding control arms

For this year’s SEMA, my friend Max Grundy built a 1950 Chevy COE flatbed truck. It’s not quite finished, but it’s close, and it looks rad on display at the show.

A Detroit-area company, PAC Racing, designed the one-off suspension for the truck. They were in a time crunch, so Max asked me to grab the control arms and weld them up earlier this year.

In my head I was thinking, “OK, cool, a set of front and rear control arms, no big deal.” Figured I’d get them done pretty quickly. I figured wrong, as these things are massive. Big arms for a big truck.

Jason Youd of PAC Racing did a killer job on the design and engineering. The pieces were laser-cut and everything fit together perfectly. My biggest challenge was going to be keeping everything straight through the welding process. In my shop I don’t have a surface place or layout table; I’m usually just working on my sculptures, so I don’t often have the need for one. So without the ability to clamp pieces down and in place, I’d need to do a smart job of tacking the parts and moving the heat around to keep everything in line.

I started by tacking the internal gussets and threaded ends into place on one surface and then added the other surface to the top of those. With everything tacked into place, I decided to fully weld the gussets. It was probably overkill, but once I started there was no turning back.

I’ve got a little #5 cup that a friend shortened on a waterjet for me, and in conjunction with a stubby backing cap, I was able to reach every joint inside the arms, at least before the sides went on. I ran short beads and moved from arm to arm to keep the heat input and warping to a minimum.

Once the insides were welded, I needed to fit the side pieces to conform to the edges of the arms. A combination of heating, beating, clamping, and tacking got the job done.

With the sides tacked into place, all that was left to do was to weld it all up. I tried to keep the beads to a maximum of 3 in. to 4 in., and again I moved from side to side and arm to arm.

The project took me a lot longer than I anticipated, but the end results were worth it. The arms are solid, look great, and they stayed straight.

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