Sheared motor shaft

[AlexBrown_1]

I was cutting out some stock for t slot nuts using some horizontal cutters on my mill lthe other night, and all was going delightfully, I thought the chips looked good and the speed and feed seemed sensible.
After a little while though the cutter I was using started to sound different, like it wasn't cutting properly and I could see some burring on the teeth, so I thought I must have been pushing it a bit hard and I switched to another cutter which was sharp, but almost immediately the same thing - chips weren't forming and it sounded like scraping and then all of a sudden it crashed and I heard a clatter at the back of the mill, and I looked around to see that the motor shaft had sheared.

It strikes me as a little bit odd that it sheared because it's the motor for the x axis drive.

Very frustrating because I couldn't work out why the cutting wasn't working properly, I've had success with vertical milling previously but not this time!

I'll get some pictures of the cutters, I think they're quite old and second hand but they felt very sharp and looked in good order.

What a pain. I'll try to replace the shaft and see how I get on with that, hopefully I can salvage the motor because it still seems to spin happily.

 

[minimutly]

Unless you can make yourself a new shaft and press it in, that motor is goosed....
No reason you shouldn't though?

 

[AlexBrown_1]

Well I think it might be beyond me to be honest, my very small press is far too small and a few exploratory taps with a large hammer moved nothing. Seems like a real shame to give up on it because it still spins up.

As promised I've got some images of the cutters and the burring, the cutters were given too me covered in rust but I didn't think that would make a huge difference? Maybe I made a grievous error in that.
The first cutter was rounded off before I got it and it looked deliberate - and it was cutting great like I said for quite a while

I'm still fairly confused about the cause of it, but I guess time to start looking for a new motor. Kind of puts me off the workshop for a bit if I'm honest.

 

[Brad93]

That's been rounded of to cut a chamfer/fillet in one corner

 

[Agroshield]

Looking at the pattern/shading on the broken off bit, I think it has been on its way out for a long time. The bottom left and top right are a different colour to the middle. Maybe the vibration from your latest cutting was at just the right frequency to send it over the edge.

 

[MCKDAVID]

for the cost of an equivalent motor, I doubt you'd save anything over getting a new rotor and fitting it etc.

put some details up on a wanted ad here, someone might have one under a bench.... unless it's a specific shaft size or stange frame size, it's probably cheaper, simpler and faster to just change out the motor directly.

 

[minimutly]

It'll be flange mounted - is it a specific type? Press the shaft out - take it somewhere with a big one, then ask on here if someone can make you a shaft. No cost to that?

 

[Brad93]

Nothing stopping you making a new shaft, is it going to be cheaper than a new motor, maybe slightly, but there won't be a lot in it.