ML7 tailstock set over a drive fit?

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ML7 tailstock set over a drive fit?

This topic has 7 replies, 5 voices, and was last updated 14 June 2015 at 08:24 by Simon Collier.

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14 June 2015 at 01:15 #193322
Simon Collier
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@simoncollier74340
I am sorting out a newly acquired ML7, 1964 vintage. I wanted to check that the tailstock was accurately on zero set over but it was immediately obvious that the adjustment screws could do nothing. It took a lot of force driving a screwdriver with a hammer between the base tenon and the main casting, after WD-40 overnight. I doubt it has ever been moved since new. Once cleaned up and oiled, again, I had to hammer it back together. It appears to the eye that the tenon and mating slot are slightly dovetailed which wouldn't help reassembly this way. Once back together, the mating parts were still so tight that to get the scale lines approximately to line up, I had to clamp the tailstock base in the vice (Al jaw covers) and use a hardwood drift and large hammer to move the body laterally along the tenon. The idea of using the adjustment screws is laughable. Can anyone shed any light on this?
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14 June 2015 at 01:15 #12493
Simon Collier
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@simoncollier74340
14 June 2015 at 01:38 #193323
Enough!
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@enough
Dunno the answer, Simon, but mine is much the same. To centre it, I've been loosening one screw then using a mallet and drift to ~~bash~~ tap the tailstock in that direction. I certainly can't lever it on the adjustment screws, particularly with that thin-slotted grub-screw (wouldn't mind finding a hex key version of that somewhere).

I'll be interested to see the responses.
14 June 2015 at 01:50 #193324
Bob Rodgerson
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@bobrodgerson97362
Simon,

I too had the same problem when I had an ML7R. Once I set it over to turn a slight taper it was an absolute pig to get back on centre. I woudn,t advise anybody to move the tailstock set over unless it is absolutely necessary.
14 June 2015 at 03:15 #193326
John Olsen
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@johnolsen79199
My ML7 is of early fifties vintage. It has never required a hammer and I would be very wary of using one on it. It is of course necessary to back off the screw on the opposite side before screwing one in to move it. It must not be clamped to the bed when you try to adjust it.

I have done tapers with it a few times. I would agree that getting it back on centre is a very fiddly job and best avoided if possible. Might be just as fast to make a taper turning attachment. I did borrow one once, much better. Otherwise you can put a centre in a boring head and use that for the offset.

John
14 June 2015 at 05:55 #193329
Simon Collier
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@simoncollier74340
Thanks for your responses. Clearly, I am not alone, so that is somehow comforting. Now that I know, I would strongly endorse Bob's advice not to touch it. John, you do not realise how tight this is. Not only do I need a hammer, but a big one, and hit hard (with wood drift, as I said). No grub screw would move this; a one inch bolt might. Some owners must have milled a bit off the tenon or slot to make it usable. I'll try to get it right (with hammer) and forget about it. Or will I have a go at it? Not sure.

Simon
14 June 2015 at 07:19 #193332
Lambton
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@lambton
A few important points about adjusting an ML7 (and Super7) tailstock.
1. The tailstock consists of two main casting, that are only clamped together by the bed clamp. This being so the bed clamp must be fully released before attempting to make any adjustment.
2. The adjusting screws work in a counter intuitive way i.e. turning one clockwise moves the casting towards the operator.
3. it is essential to slacken off the screw on the opposite side to allow the top castting to move over.
4. It is essential that tenon aligning the two castings across the lathe axis is tight however it should not be necessary to use brute force.
5. If after observing points 1-3 above adjustment is still very difficult then take the two casings apart ( no hammer needed just us a broad bladed screw driver in the slots provided each side at the top of the tenon to prise the castings apart. Gently clean up the mating faces gently to remove any paint or dried on crud. Do not attempt to ease the tenon in any way. Apply some copper type anti-seize compound to the mating surfaces and reassemble. It may be necessary to carefully use a plastic or hide faces mallet to tap the two parts back together – but certainly no heavy hammer blows!
14 June 2015 at 08:24 #193340
Simon Collier
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@simoncollier74340
All screws were removed and the clamp bolt nut. I did use a Hyde hammer except with the wood drift. I am going to measure the fit to see just how much interference there is.
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