# Adapter



## COPE 19 (Jan 4, 2016)

Being new to the hobby machining world is there an adapter so I can use R8 collets on my 2 1/4-8 lathe spindle? My mill uses R8's so I have those on hand. If not are there any collets that can be used on an old Enco lathe?


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## Bob Korves (Jan 4, 2016)

The spindle threads do not matter here, only the spindle internal taper.  See if it is MT4 or ?.  You might be able to find an adapter from MT to R8, but I have never seen one.  You might be able to make one out of a MT shank off a drill or other tool, or a semi finished arbor.  a feature would need to be added to eject the adapter from the taper.  The major disadvantage of your idea is that R8 collets do not allow the stock to go through the bore like 5C and others do.


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## TOOLMASTER (Jan 4, 2016)

some fit right into the spindle


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## Bob Korves (Jan 4, 2016)

TOOLMASTER said:


> some fit right into the spindle


Good point.  The first thing you need to know is what the spindle internal taper is...


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## COPE 19 (Jan 4, 2016)

There are no internal threads. The lathe spindle that the chuck screws  onto is a 2 1/4-8TPI external thread. The chuck itself has the internal threads or taper. I don't know if such an adapter exists. Just thought that I could use them if they did.


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## brino (Jan 4, 2016)

Bob Korves said:


> The spindle threads do not matter here, only the spindle internal taper.



Not quite true Bob.

Adapters like these:
http://www.bealltool.com/products/turning/colletchuck.php
http://www.bealltool.com/products/turning/bigchuck.php
screw onto the lathe spindle threads and allows use of collets.

I posted a whack of info about them here:
http://www.hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/#post-308310

If you do have a hollow spindle then long work can extend thru that hole.

I have never used R8 tooling.

-brino


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## Kernbigo (Jan 4, 2016)

I made a r8 setup for my 10" atlas, worked ok but was kind of touche as far as the draw bar went, it liked to through it out round on the part. The draw bar had to king of float.  I sold it sometime back. I bought a 5c set up but don't use it much.


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## COPE 19 (Jan 4, 2016)

That's exactly what I am looking for, now if I can just find a set that fits my 2 1/4 spindle. Thanks to all that helped.


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## Bob Korves (Jan 4, 2016)

brino said:


> Not quite true Bob.
> 
> Adapters like these:
> http://www.bealltool.com/products/turning/colletchuck.php
> ...


Indeed, Brino, I had completely forgotten about collet chucks, mostly due to the OP's request for using R8 collets.  I am pretty sure there are no R8 collet chucks to go on lathe spindle threads for sale.  My other point was that R8 collets are held in place with a 7/16-20 drawbar, so no stock can go through the collets.  If the work cannot go through the collet then the hollow spindle is of no use.


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## Bob Korves (Jan 4, 2016)

COPE 19 said:


> There are no internal threads. The lathe spindle that the chuck screws  onto is a 2 1/4-8TPI external thread. The chuck itself has the internal threads or taper. I don't know if such an adapter exists. Just thought that I could use them if they did.


We are looking for an internal spindle taper, not internal threads.  What brand and model lathe is it?


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## mksj (Jan 5, 2016)

You may be better off with a ER-32 or ER-40 system on a lathe, especially for holding odd sized stock. Both the 5C and R-8 have limited clamping range, and their TIR tends to be worse then the ER system. Can't say I have seen an r-8 system on a lathe, and not being ably to pass stock through the collet makes it very limited. I use a 5C system, which requires about 3X as many collets ($$)  to cover the clamping range of ER set. You can get a back plate and ER-32 (or ER-40) chuck for under $100. Sold by many vendors. They also sell inexpensive ER collet sets. Another option is to clamp an ER Collet Fixture with a round, square or Hex body in your 3J or 4J. This is the route that I will probably go, since I use an ER-32 setup on my mill. A lot easier to clamp an ER fixture in my 60lB 4J then switching it out for another chuck. A typical 5C chuck without a collet closer, is pretty slow to switch out collets, ER would be quicker. Just some thoughts.

http://www.amazon.com/DIAMETER-ER-32-COLLET-CHUCK-3901-5032/dp/B00DVTSN4C
http://www.ebay.com/itm/Threaded-Backplate-Adapter-4-3-Hole-2-1-4-8-For-Lathe-Chucks-/121801105110
http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Lathe-Collet-Chucks
http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Fixtures
http://www.hobby-machinist.com/threads/er-40-collet-chuck-for-southbend-9-lathe.38505/


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## COPE 19 (Jan 7, 2016)

It is an older Enco 12 X 36  model 92030


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