I don’t have the physical pieces in front of me, so perhaps someone with firsthand knowledge can help me out here.
The transmission provided in last year’s kit were encased in a housing made of two pieces, held together by 1/4-20 UNC bolts at the four corners. The assembly instructions spec. 1/2" length on those bolts and, similarly, the drawings show that they’re tapped to 12.7 mm.
I want to tap the other end of those four holes and bolt the transmission to a plate using four separate 1/4-20 screws so that, if I remove the transmission from the plate, it’ll stay assembled.
This seems perfectly plausible, but I am working on an abbreviated timetable and can’t wait until I see the transmissions again to be sure. Can someone verify that I’m not crazy and this is possible?
Yes, this is possible.
Not only is it possible, but that was one of Paul’s original design intents.
(He’s got this “thing” for face-mounting transmissions.)
I’ve got one in front of me, and I double checked, just to be sure.
John is correct. If you look at the manual (down-loadable from IFI website), chapter 5 shows the engineering drawing for the housing. The through hole for the tap drill is specified at 5.0mm. This is actually undersized for a 1/4-20 (but will work just fine). It is the perfect size for an M6-1.0 metric screw. In addition to “a thing” for face mounting, I have “a thing” for the metric system.
Your intended use of the mounting face is well within the design specifications for the transmission housing.
