Repairing damaged lathe plain bearing mandrel for ML4

I have an elderly Myford ML4 whose function is solely for the occasional screwcutting operation as my accurate lathes are all plain.

At some stage in its previous life the bull wheel must have come loose (it is held on by a grub screw rather than a woodruff key). The grub screw was hard and the mandrel soft, with the result that a nice groove was cut in the mandrel. To make matters worse on being dismantled (presumably for a belt change) in its past life, the point of the grub screw has cut a groove in the mandrel, through the area of the rear plain bearing.

I'm not sure of the best way to effect a repair other than turning up a new mandrel on a nearby precision lathe. It is a parallel mandrel 1.000" diameter with thread cut on one end for a myford spindle nose and with a fine pitch thread on a reduced diameter portion at the other.

I was slightly surprised to find a soft steel mandrel in bronze bearings; would have expected white metal, but then I am more familiar with Lorch lathes which used very hard plain cone bearings.

Any suggestions would be gratefully received, Alan

Reply to
Alan Bain
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I wonder if you could fill the gouge with epoxy/white metal/solder etc and see how it goes rather than launch into making a new spindle?


Reply to
Bob Minchin

Is it actually necessary to repair or replace the spindle? As long as the "peaks" at each side of the groove are removed, and the "valley" of the groove does not lead to oil loss, I imagine there will still be a considerable area of bearing surface to take the load.

Cliff Coggin.

Reply to
Cliff Coggin

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