# Between centers - my first



## Norppu (Jul 20, 2018)

So I need a fly cutter holder for my gear making assembly. Decided to make it a MT4 with a draw bar. That goes directly into the nose of my lathe. The problem is, MT4 is too big to be turned using the compound method and my lathe does not have a taper attachment. The last and probably only option is to do this between centers by shifting the tail stock. Some arithmetic is involved but not too much.

Ouch.... I do not have a lathe dog. Spent some 4 hours just making one. Now I have a very decent lathe dog.


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## Chris Hamel (Jul 20, 2018)

I made an offset tail stock center just for turning tapers.  That way I don't have to mess with my tailstock alignment.


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## Larry Hoy (Jul 20, 2018)

When I make MT tooling I make them two at a time I cut my metal 12" as the offset is given as a taper per foot. set a dial indicator on lathe carriage move to end of stock and dial in offset.


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## Chris Hamel (Jul 20, 2018)

I start with 6 inch  piece and half the taper per foot.  Actually divide it by four since it refers to diameter and I am working with the radius.


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## Norppu (Jul 20, 2018)

The magic number in here is 0.02596.
This is actually the sine of MT4 taper angle (the angle between center line and surface "line").
Since my work piece length is 189 mm the tail stock shift is 189 mm * 0.02596 -> 4.90 mm.

The tailstock method has one advantage over the other methods. The longer the work piece, the smaller are the errors in the taper angle.


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## NortonDommi (Jul 21, 2018)

I use a boring head in the tailstock and a spare shank on an extension to set the taper with a DTI on the toolpost.


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