I bought a standard throttle quadrant from Aircraft Spruce that has the throttle and mixture handles. Its body is about 2" wide including the bolt heads and nuts. I wanted to hide all the bolts and nuts (of the quadrant) inside the console, so, I know I have to carve into the foam right off the start if I want to keep the center console the same width as the heat duct (the heat duct is 2" wide including the 1/4" thick foam on both sides). It was suggested in the plan that they should be removable for inspection and maintenance down the road. To me, that means I have to have some kind of removable cover, so that I can access the throttle quadrant as need arises.
Mounting the throttle quadrant was more difficult than expected because I have limited room to work with. Here's what I did:
I marked the position of the quadrant on the console sides and Dremeled out the foam holes where the bolts go. Note I was off a bit - that was not intentional . I also embedded & floxed a couple T-nuts in the foam on each side of the console for securing the quadrant body (note the t-nut posts butt against the sides of the quadrant body). I used an aluminum strip (or a large washer) to secure the quadrant in place. The strip on the other side of the console is mounted in the opposite orientation, forming a 'X' configuration - keeping the throttle quadrant from any rotational movements.
Once I got the quadrant mounted, I decided to give it a trial fit. As always, Murphy will come visit when you least expect it . I could not slide the slots (on the console cover) over the control arms because the tip of the arms are slightly bent (intentional). I either have to re-design/re-make the cover or modify the control arms. Since I was thinking of replacing the two ball knobs sometime down the road, this gave me the excuse to make the change at this time. I removed the quadrant arms and traced them out on a 1/8" thick aluminum sheet and cut them out with a band saw. Then I cleaned up the edges with an end mill. I measured the hole locations and match drilled them on my drill press. I re-assembled the quadrant and re-fit on top of the console. Note my throttle quadrant is mounted onto the center console without external bolts and nuts as shown (left).