[How do I?] Machine Down Elec Motor Output Shaft?

[Str8jacket]

Hi,
Replacing the motor on my coldsaw with a 3 phase unit, pulled the old motor today and the OEM has machined the shaft down to accept a 20mm ID helical gear and a smaller key way.
I dont have enough material to bore out the gear so what is the best way to turn down the motor shaft?
Can i strip the motor and hold the armature in the 4 jaw and tail stock?

It needs 5mm of the length parted off too. Could i mill the excess off?

Getting beyond my skill set!

 

[Str8jacket]

 

[Tony Wells]

Yes, you'll have to tear the motor down, but machining the shaft should present no special problems. The center hole is already there, but I suspect you'll need to pull a bearing on the other end. On the other hand, it looks like a TEFC motor, so pulling the fan should give you plenty to chuck on. The first job shop I worked at did lots and lots of motor work. It's pretty easy most of the time.

 

[dlane]

Thanks for the full size pics , thumbnails no good

 

[Joe in Oz]

Why dismantle the motor? If your lathe is big enough, you can just take off the fan cover and run the whole thing between centres. Or take the fan off and chuck that shaft end in a 4-jaw (or know accurate 3-jaw). The motor housing won't spin - its on bearings. If the bearing seals have some friction and it tries to spin, just tie up the cord or stop it spinning some other way. If you have the space on the lathe, there is nothing gained tearing a motor apart to turn a shaft. Done it lots of times. By the way, turning grinding arbours mounted on the motor shaft this way is the best way to get accurate arbours with no run-out
Cheers,
Joe

 

[Str8jacket]

Hey Joe, I initially thought about doing it that way but honestly i have so little experience it scared me a bit! Turns out i would have had to strip it to machine the key way as the arbor wouldnt fit close enought to the body of motor.

All done. First job on a milling machine. Didnt stuff it! Learnt a good lesson on clamping sufficiently too, first touch with the mill and it moved slightly, glad my first job wasn't with the 100mm face mill.

I reassembled the motor and had only one small glitch with the circlip groove being a bit tight. Had to lightly run a hacksaw blade around the groove and i fit well. Hopefully the new motor gets the saw working properly

 

[4GSR]

Another pair of them "see thru safety toe shoes" being worn!

Nice job!

Ken

 

[Str8jacket]

Another pair of them "see thru safety toe shoes" being worn!

Ha ha yes they are also extremely stylish. I actually had boots on but come out after dinner last night to get some stuff and took the photos. I find my back gets too sore wearing pluggers for any amount of time but good work boots are fine even after 14hr shifts

 

[4GSR]

Have to ask, is there a reason for a "open" bearing on this motor? Is it in a gearbox or similar where it gets splash lubrication?

Yeah, I'm so glad I don't have to wear those steel toe boots anymore.

 

[Ulma Doctor]

i don't think it's an open bearing,
i think that's a seal you are looking at there Ken,
you can see the lip spring if you look real close at the picture