End The Adapter Blues

When you get bad adapters, make bad adapteraide- Wait, that doesn’t work… Never make what you can buy- Hmm, that doesn’t work either…

After getting burned by the thesuperkids adapter I decided to bite the bullet and make a better one in the machine shop with tight fitting bores, a D-shaped bore for good torque transfering and an overall length to match the Shaftloc bushing I ordered. I am aware of only a few ways to make a D-shaped bore- casting, punching or plunge EDM, all of which are not feasible for me- so I decided to get a bit more creative about it.

I figured that if I cut a slot in the bored section of my adapter matching the location of the flat in the shaft then made a key that matches the OD of my adapter and is flat on the other side to fit against the flat side of the shaft there should be no way for the shaft to spin in the adapter as long as the outside of the adapter is held in a correctly sized bore. Pictures will help.

The adapter fits very tightly over the shaft- less than .001″ oversized- before I cut the slot it made vacuum-y noises upon removing it from the shaft. There is no noticeable play in the adapter fit. It runs true too!

And fits in the Shaftloc bushing nicely

I’m sure this is no new invention when it comes to dealing with D shafts, but I hadn’t seen it before and am happy how it came out. Making careful measurements and cuts pays off. I will use a pin to secure the adapter to the shaft, but it shouldn’t end up bearing torque load with the D bore key. I think this adapter will work well- and heck it only took one night in the shop to make.

Posted on March 13, 2010 at 8:05 pm by Henry · Permalink
In: Electric Poly-V Bike

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  1. Written by ken
    on February 27, 2012 at 10:12 am
    Reply ·