Myford Metric Lathe Leadscrew

They must have progressed in the '80's as the 1979 Boxford drawing I have for cross-slide screws certainly specifies a blank dimension for thread rolling.

Edited By Pete Rimmer on 10/04/2023 08:41:46

As you have a Myford lathe, it will have a hand wheel . This can be used if you don't have a thread dial to engage the halfnut at like zero . Older machines have a lot of backlash in the system. So reversing so that you have plenty of time to take up the backlash . I hold my hand on the carriage wheel to drag it and to take up the backlash in the system. Also make sure that you have the halfnut engaged at the same level. I fully engage the halfnut handle each time. There has been alot of good tips in this thread.

On my lathe as I added a VFD, I have added a microswitch that allows it to stop quite quickly . I have mentioned this as a 3phase motor and VFD allows for easy reversing and variable speed for other situations etc. ut something to be thinking about for later down road.

Hello Barry,

I haven't done anything along the lines of fitting Oilite bushes to the Tumbler gears. I see no reason to. I think in many respects you have answered your own question when you state that there was clearly a lack of lubrication.

I have done a lot of work over the years at elevated speeds on my S7 and never had any issues with overheating of the tumbler gears. Correct lube is the answer...

Best regards,

Steve.

That lack of lube may have been due to the use of grease rather than oil.

Hi Ega, Yes use of grease decades ago could have been the cause of the poor lube problem.

Hi Steve,
I agree that proper oiling is working better now but don't agree that one should require the use of the full gear train to achieve a simple feedrate during high rev turning operations.
Also at high speeds polymer bearings are affected much more adversely from overheating than oilite bronze is on steel.
And running the full geartrain seems like too much overhead for such a simple feed requirement during high speed turning and facing operations.

IMO the real function of the geartrain is to deliver accurate pitches for screwcutting at much lower revs when less bearing (bush) heat is being generated.

Are you in the business of making and selling the 33T and 34T "metric" screwcutting gears as well as the tumbler gears? - I could do with one of each of those.

I'll continue the trial of a Variable Speed DC + Geared drive unit driving the leadscrew for an improved feed function when turning and facing at high RPM, - which is often.

Thank you,

Regards, Barry