Simple lathe operation?

[Dean jeffery]

These have an 100mm chunk i think so you'd need soft jaws bored out, or fit the face plate, 15 20 thou cuts tops on that dia and very steady parting. Been such a big dia for a small machine will make it time consuming, I've turned 80 dia down to 69mm on a ML7 but only did 8 off then sold on. Bought it very cheep to do a job and not needed no more.

[EddyCurrent]

I'm not a machinist but I've had basic machine training many years ago. I would basically do what mekanik said but I would face the end off each piece first, before going in with the parting tool. This is so I would have a nice finished flat face on each piece so they would mount squarely in the 3 jaw chuck.

[GEOFFREY]

If you only need 1or 2, the Myford could do it, but if you have a quantity I think you will waste a lot of time. my solution would be to get a friend (who has some very serious cnc lathes) to do it. If you can't find someone local I could get it done for you, but obviously there would be transport to consider. I do mot think the ML7 is the right machine for that job. Good luck with whatever you decide to do. G.

[gavztheouch]

Thanks, yes I only really need small quantities im trying to make an injection mold for a small Rabit mini plastic injection molder. The standard molds are made to fit a round hole and the hole to inject plastic into is in the center. I was thinking I could make both halves on the lathe and also drill the hole in the center for the plastic to enter plus somehow cut out the profile for the injection nozzle to fit into. Anyway I better take that conversation back to my original thread on building the mold.

[mekanik]

just thought i would try to explain a little better, i assumed for some reason you were making a decent quantity but irrespective i would still tackle the job the same way, set up your length of bar in 4 jaw with jaws reversed, clock it at the chuck end then the tailstock when both running true and chuck nice and tight centre the bar and secure workpiece with revolving centre. Turn the OD down to 80mm, working from the tailstock to the chuck set the parting tool 2mm thicker than the required finished width your disc,go in with the parting tool but leave 30mm remaining to support the bar as you continue parting your items to said 30mm depth, even if the parting isn't brilliant you will be able to clean it with a file after you have sawn the blanks off(by hand) then 3 jaw with reverse jaws face off both sides to finished thickness, yes you can do it on your lathe if it's in reasonable condition, only tricky bit might be the parting, in that case as i said earlier just go in as far as you are comfortable with(just means a but longer on the hacksaw but you still have the reference of your parting attempt. No soft dogs required, jobs a goodun.
Mike