GEC Motor Bearings for Lathe Motor

I had both a lathe and mill with belt speed selection before the current machines. I would not wish to regress to that state of affairs ever again.

Continuous variable speed machines are just more relaxing to use - and there is not the temptation of not changing the speed - on occasions where it is only a small job but would /should have been carried out at a different speed.

Drilling is just one example - from pilot to a much larger finishing size.

New bearings installed.

They are oilite bushes bored out a fraction, faced to reduce the length and then the OD was reduced by turning on a mandrel (which was also used to gauge the bearing while opening out the bore).

The rumbles and rattles are now gone. Thanks for all of your advice.

A 'before and after' photo of the bearnigs with the madrel in the background.

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A good ending, and an educational journey

Thanks for sharing.

MichaelG.

Sorry, somehow I missed this post until now. Interesting to know the origin of the bearings. I took a look at their current site but I suspect that they have moved on from electric motor bearings. So basically my motor is (very) tenuously related to the Vanwall racing cars... which if memory serves were rebadged Ferraris.

The shaft diameter still puzzles me though. Hopefully my modified oilite jobs will fit the bill.

Regards, Andy

Not sure why the sizes are such a puzzle. The bush length at 0.376" measures 1 thou over 3/8". The outside diameter at 0.4218" is 2 tenths of a thou under 27/64". The shaft diameter at 0.316" is 3.5 thou over 5/16".

Your motor is nearly 50 years old and its design origins probably pre-date its manufacture to some degree. Fractional imperial sizes were still in common use at that time.

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Sorry but I'm not convinced by that explanation for the shaft diameter

+3.5 thou would be an enormous oversize on a nominal 5/16"

I would suggest it more likely that 8mm is the nominal size [giving a 26 micron oversize]

MichaelG.

I tend to agree on the shaft size Michael, although I will always consider errors in measurement first. In this case I think that Andy has been consistent and accurate.The other dimensions do look rather close to imperial fraction sizes though. On other things that i have worked on that were manufactured before and through the middle of the last century, it is not unknown for mixed imperial and metric dimensions to be used for parts!

Main thing is that the problem has been resolved!

Yes I did doubt my measurement so I had to think up a way to check whether my mike was wrong (hopefully not given that it's a Moore and Wright!).

Not having any slip gauges or anything similar to check against I miked the back end of the spindle on the lathe and compared it with the drawing that can be found on one of the forum threads here. My reading came out within the tolerance band so I was reasonably convinced that my mike was reasonably OK.

As confirmation, the 8mm bearings when they arrived would not go onto the motor shaft until I bored them out by a few thou.

No problem Andy, I had a quick look on the website too, and it looks like they are IC bearings only now! I shouldn't think you will have any more problems, and TBH I doubt if you would find these bearings even as "new old stock" I have serviced many of this type of motor, and it was very rare that the bearings were worn to any extent. Give it some oil now and again, and it will be fine.

Edited By Phil Whitley on 04/11/2018 18:58:01