Myford 1/2hp motor woes

[dickdastardly40]

It has become time to move on my S7B, I work away from home and it hadn’t done much and sat for a couple of years under its cover. I cleaned out the tray of all the congealed Nuto 32 and photographed it, then looking properly noticed that the rubber motor cradle mount was a bit ropey!

I took the motor off and saw that both rubber bushes had completely perished. I’m torn now as a quick internet search shows the cradle mounts available but until I can get advice as to the exact size I don’t know if I can repair the original 1/2 phase motor.

I could spring for a replacement single phase motor if new bushes are unobtainable or perhaps speculate to accumulate and fit a 3 phase motor and inverter as I’d always intended and increase the price in line. I don’t think trying to sell it as is is likely.

Firstly can anyone point me at the exact cradle mount bushes for an English Electric 1/2 hp frame ms 5126 motor?

Secondly, what do you think, repair, new single phase or new 3 phase motor? Will I get a return on the investment or not even of it does make it more saleable?

TIA

[jackrae]

I believe the recommended single phase motor for an S7B is 0.75HP.
Given the option the ideal choice is to go for an inverter unit driving a 3phase motor

[coniston]

It really depends on the value of the lathe as to whether a new motor or repair is better. If the lathe is in first class condition and well tooled then the addition of a 3phase motor/inverter will be a great selling point. Whether you get your £450 or so back in the added value will be a moot point. I have just done the same conversion on my S7B and it has made such a difference, much quieter and ultimate control. You could keep an eye out for a SH motor but good ones don't come up too often. Advertising with either a new Single Phase or Inverter drive will certainly make it more attractive. I believe the early S7's were shipped with 0.5HP motors and the 0.75HP motor came in on the Mk2 lathes.

Chris D

[92220]

It depends on what funds you have available. As said, a 3/4hp motor is the recommended size. If you have the funds, buy a Newton Tesla variable speed unit that is actually designed to just bolt straight onto the Myford. It comes as a variable speed, and reversing, control unit plus the motor. It comes all wired up to plug connectors, and just needs plugging in when fitted.

Worth ever penny!! I've had mine for over 12 years and if anything ever happens to the control or motor, Newton Tesla will sell you the parts you need to replace, which you can just bolt on, but I've not heard of anyone ever having a problem with their control units anyway. Variable speed is a great selling point.

Bob.

[john42coleman]

My Myford motor conked out several years ago and replaced it with a Newton Tesla plug in unit. Wonderful piece of kit, wish I'd changed over years ago instead of it becoming a distress purchase.

[timo]

I would certainly not go down the inverter / 3 phase path if you are moving the lathe on as you will never get your money back. If you were keeping it then it is one of the best modifications you can do. I replaced a 0.5HP single phase motor which did all I ever asked of it with a 0.5HP three phase and inverter, both bought second hand for a total of some £75. I made my own pendant from components I already had in stock.

If I were you I would offer it as is but with an explicit £50 discount to cover repair or replacement of the motor. That way anyone buying it can a) repair the current motor, b) get another single phase motor or c) put on a 3 phase motor and controller.

Bear in mind that the pulleys on certainly the earlier Super 7's had an imperial hole for the motor shaft. Most modern motors will have a metric shaft unless you check / specify otherwise which then means bushing or machining the pulley. Guess how I know ........!
Tim