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Finding a Good Coupler

4422 Views 50 Replies 7 Participants Last post by  57Chevy
Hi everyone,

I'm in the process of choosing a coupler to mate my Warp9 DC motor with my Mini Cooper manual transmission and I've come across a couple of options. I'm browsing and their Rigid Couplers here and I've come across a few coupling types that I think will work for my conversion. Here are the different types (on the website):
Font Line Auto part Rectangle Cable

I've heard that these types of couplings have been successful in EV conversions so I thought I might give one a try. I'm leaning towards using either the 1-piece clamp rigid shaft coupling with a 1.125 inch bore diameter:
Rectangle Auto part Electronics accessory Plastic Font

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Or using the 1-piece set screw rigid shaft coupling with a 1.125 inch bore diameter:
Rectangle Camera accessory Auto part Font Technology

Link (Rigid Shaft Coupling: 1 1/8 in Bore Dia., Steel, 1 7/8 in Outside Dia.)

Are their any benefits/drawbacks to using one coupling over the other? I'm thinking of having a machine shop cut and weld my clutch plate onto the transmission side of the coupling. What does everyone think of this? What coupling do you recommend?
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You've shown that the upper half of the black coupler is useless and what he has is going to be an out of balance mess.

That weld is cold, almost looks like it was "aluminum welded" vs TiG welded using one of those special rods that works with MAPP gas. That weld makes that assembly a writeoff. Can't be fixed for service.

Next go...cut the black coupler in half to where only two cinch bolts are used and a sliver above the factory gap.

Groove the spline piece and the new baby two bolt coupler for welding HALF way around, like its amputated friend was joined.

Get it TiG welded, several passes, then chuck it in a lathe and fillet the weld so it's balanced and there are no stress points (sudden geometry changes...ridges, etc). You may need to take it to a machine shop and a competent welder vs guys who do joints on irrigation stuff.
^ This. My daughter called and interrupted me typing this very same suggestion up.

The problem might be that there won't be enough meat over the splines to get to motor diameter, but that just means reaming half the coupler to a larger ID...but only if they don't already stock couplers in two different ID's.

No welding needed..
Why are you married to the coupler brand? Find one that works.

Making a keyway in a uniformly cylindrical (turned to same diameter full length) hub is trivial for a well equipped shop. Takes 10 minutes.
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