The Shiftec Air Power Source (APS) provides compressed air to the shift servo. I designed a mounting bracket using the tab-and-slot approach with relieved corners discussed in a previous post. SendCutSend’s price point and quick turnaround is a game changer. It only cost $48.46 to have the following six different parts laser cut from 1/8” 6061, deburred and delivered within one week.
Center plate, four side plates and a backer plate to mitigate stresses applied to the center of the chassis tube
Welded aluminum tabs don’t look as nice as steel ones, so I decided to grind them. This reduces their strength, but this isn’t a structural piece and there are weld beads on the underside. If I were to remake this part, I’d keep the same number of tabs and slots because they facilitate fixturing and significantly reduce warping, but I’d only weld two of them before doing the beads on the backside. This would reduce the amount of welding and grinding.
Before grinding
After grinding
The APS is a well-engineered unit that’s designed to be quickly serviced. It mounts with two spikes that insert into rubber grommets and a single screw that mounts onto a vibration-dampening sandwich mount, all of which helps isolate the APS. I haven’t drilled any lightening holes in the large horizontal plate yet because I might mount the parking brake ECU to the underside.
The spikes slide into the grommets and the tab is bolted to the vibration-dampening sandwich mount
I’ve had challenges drilling straight holes in the past. Since the screws mount through the bracket, the 2” x 2” chassis tube and the backer plate, it’s particularly important that the drill is held perpendicular to the chassis tube. This can present challenges even when you have good access and can easily eyeball everything. In this case, the body made it impossible to line things up vertically.
To get the holes near perfect, I clamped the backer plate to the chassis tube so that I could use its laser-cut holes to index the largest drill bit that would fit. I then slid the drill guide over the bit and clamped it in place. Once a hole was drilled a screw was pushed through and tightened. A high-quality, alloy-steel drill jig costs about $25 and I highly recommend picking up a standard and/or metric one.
Backer plate and drill jig clamped to the chassis tube. Two holes already drilled and through bolted.
APS installed in lower left
I will also add a thin closeout panel under the APS after I get all of the lines run. The next step in to run the air line.