Question on tolerances on 8mm F. Lorch lathe

alonsojar

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Nov 21, 2011
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Hello,
I have a 8mm Lorch lathe that I bought time ago. I'm happy with it because the head runs true and I've been able to do several quality jobs using the set of original collets. On my last job I had to use the tailstock to drill a small hole and to my disappointment I've realized that the tailstock is not perfectly aligned with the head. The tailstock is a bit down the head center. Just that, no lateral error. After several measurements this error is aprox 0.12 mm (0.0045 in). I've checked it in all positions of the bar and using different centering tools in the tailstock and is always the same.
I cannot see damage in any part and the tail is also the same brand, so I think the error could be because head and tailstock were originally from different lathes and now are not matching... Of course I don't see any way to adjust this misalignment without ruining the lathe.

Should this error be considered as normal in this equipment or is too big to be acceptable?

I'd really appreciate any comment.

J. Alonso
Spain
 

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wefalck

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Mar 29, 2011
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0.1 mm offset is definitely too much. I haven't seen that much on any of my lathes.

Looking at your lathe it indeed appears that head- and tailstock came originally from two different lathes - judging by the different state of the nickel plating. Lorch, Schmidt & Co. and the other makers asked the lathe to be returned to them for adjustment, when one bought additional tailstocks and other attachments where alignment is critical.

Unfortunately, I don't see a possibility to adjust the centre-height. Lateral misalignment could be due to a worn pressure pad or dirt and could be adjusted. Perhaps you should also try to check, whether the axis of the tailstock is parallel to the bed. A slight dip could produce the misalignment you observe. Your headstock is almost certainly of German origin, as it was meant to be on the right of the operator (German watchmakers operated the handwheel with the right hand and used the graver with the left ...). The tailstock could have come either from a German or an exported lathe. If the axis slightly dips, using the tailstock on a lathe where the headstock is on the other side of it may not have been perceptible.

Perhaps you should find another tailstock/lathe on the electronic bay, so individual tailstocks seem to become rarer these days.

wefalck
 

alonsojar

New Member
Nov 21, 2011
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Thank you for you wefalck for your advice.

I was thinking this offset is big for a watchmaker lathe, but I was needing to confirm it. It's my first lathe.
As you caught at first sight the tailstock has the nickel plated more worn than the head. Other than that the lathe is ok. It came in it's wooden box with a complete set of original collets from 0.2 to 5.0 mm increasing by 0.2mm and also drill bits, centering tools, pivot polishing, wax chucks etc. This is a German lathe and as you noticed is intended to be used left handled, but I use it in the reverse setup because I prefer to use the right hand to hold the gravers (I don't have a cross slide).

I've checked meticulously everything looking to correct this misalignment, but nothing to do. The tailstock is parallel to the lathe bar. I've also inverted all pieces to it's original left handed setup, but nothing changes. All is fine except both centers doesn't match. It would have been great if manufacturer could as you said realign it. Sadly a bit too late now!

I will try to find in the bay a new tailstock or a set of head-tailstock and see if this time the offset is more acceptable.

Thank you again for your ideas and information.

J.Alonso
 

Dr. Jon

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Dec 14, 2001
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I have a 6mm Lorch in its box with a large collection of accessories and no reason to think any parts are replaced. Mine has s similar offset between the head and tailstock.

It seems to be either they were not that accurate or they go out with time.

It is one reason I don't use it a lot. Another issue is that I cannot get a tip over rest which really slows down other turning operations.

For these reasons I use my American style lathe. On these you can shim the head and tail stock to alignment.

If you want to use your lathe and since yuo have paid for it and it is your only one I suggest you make an adjyustable drill holder.

One way to do this is to take a center and drill it out parallel but offset from center. It should be well over 1/8 diameter. Now take piece of drill rod which fits the hole and drill a 1/8 hold also off center. A tapped hole for a set screw is useful .You can then put a lot of drills on 1/8 shanks in the inner rod, put that rod ihnot the tail stock and rotate the holders to center the drill.
 
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