[KohKohPuffs]

Originally Posted by asid61

+1 on using a smaller custom rod.
Using a 3/8" hex shaft could be possible if you used custom Dog stuff, but ballshifting would be very tricky. On the plus side, you could use the 3/8" x 7/8" flanged bearings, which are very compact, for your dog gears.
Using two different pitch gears on a shifter seems interesting but also risky.

The main thing I would be worried about if you reduced the rod diameter is the little shifty bit (4-40 screw in WCP dogs). SW stress analysis could make sure it's safe.

My applications for using a shifter rod in a 3/8" hex shaft is for a brake for an arm gearbox. I would prefer to use COTS parts for the sake of machining time and because I know through experience that those work perfectly well without failure (as much). My main concern is if there's a limit to what size hole you can make in a shaft for the shifting rod to go through. Of course, I'm not going to make a hole in a shaft and leave only 0.01" of wall thickness, but I'm wondering if there is a general rule to follow.