That very much depends on what lathe you have

Hi Sean,

My advice would be ER-32 collets. On my small lathe the mandrel has a bore of 20mm, so I made a ER-32 collet chuck for it. I have also made an ER-16 collet chuck with a MT 3 arbor. I bought the appropriate ER collet nuts, my machining skills isn't great and even cheap Asian collet nuts are better than what I can make. The collet chuck for the lathe is mainly used for work holding. I also have an ER-32 collet chuck with MT 3 arbor that I use in my milling machine, so I can use the collets either for workholding or for holding end mills. Good luck with the project.

Thor

My choice has been ER Collets, since they cover a nominal size range of 1mm (0.5mm for the smaller types such as ER11 and ER16) and so can be used for Imperial as well as Metric round material / items. The handy thing, in my view is that the holders all use a 1.5mm pitch thread, (saves me having to think/remember).

ER11 covers 1mm to 7mm; ER16 covers 1mm to 10mm, ER20 covers 1mm to 13mm, ER25 covers 1mm to 16mm,

ER32 covers 2mm to 20mm, ER40 covers 3mm to 26mm.

ER collets are also available for Imperial sizes, according to the Arc Euro Catalogue.

5C collets can be obtained, in various Metric and Imperial sizes to hold Square or Hexagonal material, as well as round.

It may still be possible to obtain new Myford collets, but will need the special Opening/closing tool.

There are other varieties of collets available, probably, mostly secondhand, now, but still useable. These are likely to restricted to only being used with material of the stated size, if injury to the collet is to be avoided.

Others, far more expert than I, will tell you that to cut a Metric thread on a lathe with an Imperial leadscrew, you will need, ideally, a 127T gear, or for slightly less accuracy a 63T gear, in the train of change wheels Others will tell you of other change wheel combinations which will achieve the same end with acceptable accuracy.

For someone with a lathe with a Metric leadscrew, the same process will allow Imperial threads to be cut.

HTH

Howard

Edited after seeing lathe details – Thor has it nailed.

Regards,

Richard.

Edited By richardandtracy on 30/06/2017 10:00:34