One very large can of worms!

[SillyOldDufferModerator @sillyoldduffer]

Before my mini-lathe went to a good home I experimented extensively with the effect of bolting it down versus not bolting it down. So far as I could tell it made absolutely no difference.

My new (bigger) lathe is different. It would probably benefit from being bolted down as there's evidence of slight vibration at certain speeds. I put this down to the bigger machine being proportionally relatively less massive than a mini-lathe and, on it's stand, having a comparatively high centre of gravity. It also has more power and heavier work to do.

Another job for my list.

Dave

[Ian S CParticipant @iansc]

Martin, my workshop is not quite that draughty, well not in the back where my machinery is.

My theory about bolting the lathe to alter the twist of the bed is that in general, with the bench likely to be used is rubbish. The bench would need to be a number of times stiffer than the lathe, A bench like the sheat metal ones would bend before the lathe did, it would need to be a heavy cast iron stand, and it becomes part of the lathe, or maybe a concrete bench would be another way to go.

Ian S C

[Ian Skeldon 2Participant @ianskeldon2]

Hi All,

Many thanks for the various tips and advice given so far. Here is the current status,

Lathe bolted down and no twist evident, in fact difficult to induce any on the bench that it sits on, so maybe that was luck from the start.

The head bearings are brass or bronze, (not looked close enough to know for sure) but no play at all detected with the dti.

Spindle nose only 1 thou run out ( I ended up buying an imperial dti).

Borrowed a Parallel bar, 2mt has only 2 thou run at 8 inches from the head and the tailstock is perfectly aligned.

THE BAD NEWS…. The chuck is awful, a bar placed in the chuck runs out by 7 thou and that is after I have worked the chuck to death to get it right.

I am going to try one more trick with the chuck before I accept defeat with it and save to buy a new one. The current chuck is a Chester Feurda ?

Thanks again,

Ian Skeldon

[HopperParticipant @hopper]

That's a pretty good reading on your spindle etc for an old lathe. You might improve it by tightening up the headstock bearings, or not. They would be bronze btw, not brass. But as they are working acceptably well at this stage you might be best to leave them alone.

Disappointing about your chuck. I had thought of buying a Fuerda for my old Drummond from the local machinery house but think I might stick with the old Crown now. You can true them up by putting packers or a "clover leaf" between the jaws and grinding them out with a Dremel type grinder as the chuck rotates on slow speed. It gave my old Crown a new lease of life.

The repair worked quite well. That old chuck successfully holds milling cutters of all sizes without runout or slippage as well as the usual turning duties.

Edited By Hopper on 26/09/2016 00:38:32

Edited By Hopper on 26/09/2016 00:46:19

[Ian Skeldon 2Participant @ianskeldon2]

Hi Hopper,

Great tip, I will give it a go and let you know how it works out,

Many thanks,

Ian

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