pic: FRC558's modified VEXpro Drive in a Day

[JesseK]

Originally Posted by TD78

I should clarify. I was not looking to form 3/8"-16 threads (or similar) using a die...I was thinking about drilling and tapping the ends of the steel rod (using a drill and tap). The rod would become a stiffening dead axle (although you don't advocate that practice).

Ah, I see. If you mount through the bolt rather than the axle (i.e. the mount hole is 1/4" rather than 3/8" and the 3/8" axle is the stiffening rod) then I don't know if there would be axial load on the bearings.

I would worry about the 1/4" bolt elongating the mount holes after a rare hit - like one that tips the bot up a bit, then the bot slams back to the floor, or like what happens when coming down off of a ramp/bump. We experienced some of this in 2007. When we went back to this style of dead axle in 2011, we used 3/8" rods and also used 1" angle brackets (1/8" thickness) to mount the wheels below the 1x1 frame. This gave us flexibility to change a mount out if we had problems. The "look" of the drive train where we mounted the wheels was similar to the old IFI KOP frame rails.