ECM 1/2 inch shaft to 1 1/4" collar

[Rover]

OK this is going to sounds a bit nutsy, but for those of us that have played with the GE ECM motors as turbines, we have been stuck with 1/2 diameter shafts (4") .

Normally I pass the shaft through an additional 1/2" flange  bearing in front of the ECM , to reduce any impact on the ECM itself from the blades & hub wiggle,force etc

But then I always have the issue of making/finding a 1/2" hub, and some other stuff.

Now I'm using a 1hp ECM with the same shaft and intend to to mount 5' diameter blade/hub , and want to get away hanging the hub on the 1/2" shaft.

The thought was to machine a 3.5" long piece of steel to do the following
1.75" inches long down to 1 1/4" diam
remaining 1.75 down to 1" male threaded diam
center bore the entire piece for the 1/2 inch ECM shaft
2 set screws in the 1 1/4" section to attach to ECM shaft
1" threaded would hold hub

I would then use a 1 1/4" flange bearing in front of the ECM to hold the collar/arbor assembly. (it would cover the set screws in the 1 1/4" collar section)

Thinking about it now though, I may be worse off , as if I don't get a very snug fit between the shaft andthe collar, I may get wobble back to the ECM bearing

whole thing just a bad idea?
 

[wolfie]

if you have the machining facilities ....make the centerhole of the sleeve exactly the same size as the shaft or 9because of the small diameter) .0005 or less smaller.  when ready to assemble heat the sleeve checking with a bore gauge till you have .002 or more clearance and slip it on. it will lock in place in moments as it cools, then add your set screws as insurance. if you cant set it that way make sure you try to 'spot' small divots with a drill where the set screws go so they actually go into the shaft.

shaft stock is usually very hard, and set screws tend to loosen, and at those smaller sizes they don't have a lot of grip anyways. and remember, loc-tite is your friend

[Rover]

Thanks for the reply

I won't be doing the machining, but someone I trust will be.  The ECM shaft is a "C" shaft with a flat, I normally dimple the flat for the bearing sets so that's not an issue.

I'm just wondering with the assembly if we can get the tolerance close enough so that as it rotates in the front mounted 1 1/4" bearing, we don't transmit a wobble back to the ECM's integral bearing

I may be better off just using a 1/2" bearing as I have previously, and an new collar/arbor immediately after the bearing to hold the hub.