vintage lathes

I am looking out for a Drummond M or ZYTO or similar vintage lathe, just wondering if anyone has converted such a thing to variable speed motor drive with the motor mounted right on the headstock, and just a minimal length drive belt ?

Save your money, M's aren't meant to be run at more than 5-600 rpm anyway

The backgear gives you huge amounts of torque for milling etc and a standard 0.3 or 0.5HP motor will give you various speed options

Get a standard M setup to start with, then see if the expense is worth the effort

The standard setup can do amazing amounts of work with a decent constant rated motor, working hard 8-10 hours a day kinda stuff, it's a proper semi professional machine

I reckon that some of the milling sessions I did in my early days would have fried anything with electronics

I can't see any advantage at all in fitting an expensive variable speed to an old machine. Industry has been using fixed ratios since the machines were invented and the ratios are suitable to cover all diameters of work in a lathe or cutters on a mill even on rapid production work. The cost of a variable speed does not, in my opinion, justify the only real advantage of not having to spend a few seconds shifting a belt to the next pulley. The reliability of the pulley system is obviously likely to be best too. Colin.

From what I see, electronic speed control is actualkly a cheap way of getting rid of the gears/back gear. If you need low speed you can't really beat the back gear system, as the speed is reduced, the torque goes up, and the motor keeps running at it's design speed, if you reduce the motor speed the torque goes down, and the cooling fan in the motor becomes inaffective. Ian S C

There is one big advantage Colin. A three phase motor has more or less constant torque throughout it's rotation while the torque output from a single phase motor varies with it's angular position resulting in vibration.

Since fitting an inverter drive to my 1950 ish lathe I get a much improved finish. However I still do most of the speed changing with the belts.

Russell.

Well said, Russell

MichaelG.

I get an excellent finish with a single phase motor driving each of my two flat belt driven lathes. No vibration effect. Colin