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Boley 6.5mm stepped ring collets (fir tree shape)

dave-b

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Jul 28, 2010
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Hi all, I recently had the luck to find a complete set of 5 Boley 6.5mm stepped ring chucks (fir tree shape) These expand on a short taper on the lathe nose as the drawbar is tightened. Not all lathes have this taper, and sods law says mine does not. I may have to grind a taper myself, but the problem is measuring the angle in the collets. can anyone measure the nose angle on their lathe? (closest I can measure is 60 degrees incl.)
Cheers.
 

wefalck

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Mar 29, 2011
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Sure that the lathe has no tapered or rounded nose ? Sometimes the nose is only bevelled for a short distance ... I found that ring-chucks are not interchangeable between manufacturers, their spindle-noses are different. Perhaps you lathe is not Boley, but Wolf, Jahn & Co. ?
 

dave-b

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Jul 28, 2010
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Sure that the lathe has no tapered or rounded nose ? Sometimes the nose is only bevelled for a short distance ... I found that ring-chucks are not interchangeable between manufacturers, their spindle-noses are different. Perhaps you lathe is not Boley, but Wolf, Jahn & Co. ?
Yes, definitely a Boley,but it is a bevelled-edge bed type.
I also have a TC&M. They are completely flat on the nose - not even a chamfer there.
Dave.
 

wefalck

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OK, this is a very old one then. Not sure they already had these collets at that time.
 

Dr. Jon

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Just a thought. These collets are very rare and I would think long and hard about grinding them if you were thinking of grinding the collets. Similarly I think grinding the head stock is a bad idea. Instead I suggest you make a tapered ring that goes on the headstock and mount it between the collet and the flat headstock. You might consider grinding a groove on the headstock and slot on the ring to get it centered.

Sonce the ring is small and removable, you can cut and try until you get one that works with little risk to the headstock and collets.
 

dave-b

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Jul 28, 2010
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Just a thought. These collets are very rare and I would think long and hard about grinding them if you were thinking of grinding the collets. Similarly I think grinding the head stock is a bad idea. Instead I suggest you make a tapered ring that goes on the headstock and mount it between the collet and the flat headstock. You might consider grinding a groove on the headstock and slot on the ring to get it centered.

Sonce the ring is small and removable, you can cut and try until you get one that works with little risk to the headstock and collets.
Thanks for the ideas Doc. I am aware of the rarity of these collets. I could centre the ring by making it a larger diameter than the nose and cutting a step to match the nose. This would only need a longer drawbar. I am always very reluctant to modify any old tooling,but my thoughts were that later lathes originally had a taper . Would have been nice to know the original taper, though. (or I could just wait until I find a later headstock)
Dave.
 

wefalck

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Mar 29, 2011
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The taper or bevel on the spindel would need to be ground with the spindle in situ, in the headstock, in order to make it run absolutely concentric. On my lathes this bevel is rather short, about 3 mm long.

I would try to take an internal impression of the taper in your collets using say plasticine. From this you should be able to measure the angle of the bevel. Before you do this, however, make sure that the outside diameter of the spindle fits into the collets and down to the bevel. I found that on some makes this can be a problem.

Grinding out these collets is not possible. They would most likely not run true anymore. Not sure how they did this originally, perhaps with a bored and appropriately dressed stone. Also not sure what would have been ground first, probably the internal taper and then the outside steps. The collets would have been slotted afterwards.
 

dave-b

Registered User
Jul 28, 2010
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The taper or bevel on the spindel would need to be ground with the spindle in situ, in the headstock, in order to make it run absolutely concentric. On my lathes this bevel is rather short, about 3 mm long.

I would try to take an internal impression of the taper in your collets using say plasticine. From this you should be able to measure the angle of the bevel. Before you do this, however, make sure that the outside diameter of the spindle fits into the collets and down to the bevel. I found that on some makes this can be a problem.

Grinding out these collets is not possible. They would most likely not run true anymore. Not sure how they did this originally, perhaps with a bored and appropriately dressed stone. Also not sure what would have been ground first, probably the internal taper and then the outside steps. The collets would have been slotted afterwards.
Thank you Welfalck. I certainly would not grind the collets . I tried by trial and error to check the collet taper by cutting a tube to fit and checking with blue, but the shortness of taper made it difficult to be sure. You are quite right - a tapered filler piece would not work for the reason you gave.namely it would have to be cut while securely fitted to lathe nose. As this is becoming surprisingly problematic I may just leave it for now and await inspiration ( or a new headstock.)
Dave.
 

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