Metric Threading

[jroma1]

]I have a Harbor freight 9 x 20 lathe,sometime in the near future I will want to purchase a blank backplate for a 6" 4 jaw chuck. My dream is to completely machine it to fit the chuck including cutting the threads. I believe the thread is an M39 x 4.

If anyone out there has already done this would they be willing to share there experiences as to,"How To Go About It".

Most important is it Possible to do this on the 9 x 20 considering it's size?

If Possible:
1 - Is the thread angle same as the American thread (60 Degrees)
2 - What are the two gears required (a & b) and are they commerically available to fit the 9 x 20,also is there an estimated cost.
3 - Is the procedure the same as the American procedure and what angle is the compoud rest set
Any suggestions recommendations greatly appreciated.

Regards
John Romano

[acondit]

John,

Not to put a damper on enthusiasm, but why not buy one already threaded from LMS (Little Machine Shop).
http://www.littlemachineshop.com/pro...ProductID=1922

They only cost thirty bucks and the hardest part is already done.

However, if you insist, then here is the info on the gear setup. I show how to fit a new back plate and chuck on my website. Steve Bedair made one from scratch from a hunk of steel on his lathe.

Alan