Small variable speed motor needed

[Newlands]

I have a watchmakers lathe which came with an old washing machine motor when I acquired it - totally unsafe electrically with exposed terminals etc, so I chucked it. I now need something a bit more sensible - I would imagine that around 100-200 watts would be sufficient, and variable speed would be nice.
I've been looking on eBay at sewing machine motors, but it looks as though they are all controlled with a variable resistor (at least the older models seem to be), although at around £30-40 they aren't ridiculously expensive.
But those that know about such things might be able to suggest something more appropriate??

 

[dieselsamurai]

I think this Question is very much budget dependant , For lathes 3 phase gives a much smoother delivery such a small size might not be practical then you are looking at a DC motor for which you would require a speed contoller and a supply . The main issue will be getting enough torque and the speed range right

 

[Kram]

I have a slightly more powerful motor that came with my lathe if your interested. 700w or so, 4500rpm max speed and was set up on a 2:1 or 4.5:1 ratio originallly with belt drives. Its 200v DC and I have the controller for it. Variable speed but the power drops greatly with that, but likely more than adequate for a watch makers lathe.

 

[Kram]

Alternatively, and perhaps a more sensible option is to drive it by one of these brushless drills. The motor has decent power and should last well as its brushless, and the gearbox gives a good reduction to a usable speed range. The problem for you will be to find a decent 20v power supply or to use batteries.

https://www.amazon.co.uk/dp/B0D7MCHQ4Y

Shouldnt be difficult to replace the switch with a potentiometer.

If you wanted more power, then there are brushless chainsaws with bigger motors for under £40 which may do well, but likely not set up for variable speed as that tool doesnt need it.

 

[Agroshield]

Please read this thread:

Variable Speed Motor for Taig Lathe?

Let me preface this thread by saying that I know very little about electronics. However, I want to modify my Taig lathe by replacing the AC motor with one that I can use a reduced speed. The lowest spindle speed on the stock Taig is around 525 rpm. I have seen that many have converted to a DC...

www.homemodelenginemachinist.com

 

[ajlelectronics]

I've been looking on eBay at sewing machine motors,

Sewing machine motors get replaced with far more controllable servo motors. Perhaps that might be an option?

 

[hotponyshoes]

Alternatively, and perhaps a more sensible option is to drive it by one of these brushless drills. The motor has decent power and should last well as its brushless, and the gearbox gives a good reduction to a usable speed range. The problem for you will be to find a decent 20v power supply or to use batteries.

https://www.amazon.co.uk/dp/B0D7MCHQ4Y

Shouldnt be difficult to replace the switch with a potentiometer.

If you wanted more power, then there are brushless chainsaws with bigger motors for under £40 which may do well, but likely not set up for variable speed as that tool doesnt need it.

12v Drills would probably be powerful enough these days.
Might be easier to find a 12v power supply?

 

[Newlands]

Just for reference, this is the lathe, along with the countershaft. It's about 350mm long. I'm not sure something like this would look the part with a butchered chainsaw driving it !
@Agroshield Thanks, that's very interesting, and seems to confirm what @ajlelectronics is suggesting. I have found a couple of Parvalux motors on eBay, but the only variable speed ones seem to rely on rheostats for speed control. I'll have a look at servo motors. Both servos and the Parvalux options are more expensive than the s/h sewing machine motors I originally looked at, but it might be worth spending a bit more to make sure it ends up being useable rather than a bodge.

 

[Kram]

12v Drills would probably be powerful enough these days.
Might be easier to find a 12v power supply?

This would likely do it, need to be in a swarf proof enclosure though! Adjustable voltage looks quite useful.

https://www.amazon.co.uk/BREUAILY-Universal-Switching-Transformer-Industrial/dp/B09YHD61B3

 

[Kram]

I'm not sure something like this would look the part with a butchered chainsaw driving it !

You would take the motor out and make a suitable fixture for it. Your results only limited by the effort you choose to put in... I'll grab a photo, I am planning to do similar for a milling spindle for my lathe.

 

[Newlands]

You would take the motor out and make a suitable fixture for it. Your results only limited by the effort you choose to put in... I'll grab a photo, I am planning to do similar for a milling spindle for my lathe.

Yes, it was just a daft throwaway comment, and I did give it some thought as I have a couple of old Ryobi drills that could maybe work. The problem is that often the inside of power tool cases are moulded to take the brushes, bearings, switches etc and it isn't particularly easy to extract the innards and re-use them. I think I might go down the servo motor route, and maybe use Aliexpress rather than eBay.
I'd be interested to see your plans for a milling spindle when you get round to it - sounds interesting

 

[voipio]

Mains powered brushed motors (universal type) can be controlled by a triac light dimmer type control. The back EMF of the motor gives some feedback to the controller's triac firing point, so that it runs at nearer to a constant speed under load, than a simple variable series resistor.type controller.

 

[Kram]

The problem is that often the inside of power tool cases are moulded to take the brushes, bearings, switches etc and it isn't particularly easy to extract the innards and re-use them.

A brushless has just a stator, rotor and two bearings, so a simple bearing motor housing is quite easily made on a lathe. If you dont have a second lathe you may need to temporarily rig something up..

 

[Kram]

I have a slightly more powerful motor that came with my lathe if your interested. 700w or so, 4500rpm max speed and was set up on a 2:1 or 4.5:1 ratio originallly with belt drives. Its 200v DC and I have the controller for it. Variable speed but the power drops greatly with that, but likely more than adequate for a watch makers lathe.

Heres a few details. Note that the motor is good, it was the speed controller PCB that was blown but I repaired it with new SCR's. I used it after to turn the new pulleys for the conversion.

New motor and vfd?

Ive blown the warco lathe motor, and wanted a new one anyway with more low speed torque. It is instantly tripping the 30A circuit breaker, nothing else turned on. Im suprised the lathe control fuse and plug fuse is fine. Please recommend a motor/vfd, if that is the best type? Current motor...

www.mig-welding.co.uk

Also consider with AliExpress VFD's being so cheap, a small 3 phase motor? People on here occasionally have used ones for sale. That will be the best cheap option.

 

[DAPPH]

I have a watchmakers lathe which came with an old washing machine motor when I acquired it - totally unsafe electrically with exposed terminals etc, so I chucked it. I now need something a bit more sensible - I would imagine that around 100-200 watts would be sufficient, and variable speed would be nice.
I've been looking on eBay at sewing machine motors, but it looks as though they are all controlled with a variable resistor (at least the older models seem to be), although at around £30-40 they aren't ridiculously expensive.
But those that know about such things might be able to suggest something more appropriate??

Have you looked at a plug in variable speed controller .

Mine works on my drill press and hand held non soft start drill from TEMU or Ali express stocks held inth UK if it says so on the listing , for about £12 IIRC .
Mine came with an American kettle lead power in it and had an American kettle socket out ., I chopped the lead in half the female male end got a UK 13 amp plug put on n it and the other end a single fly lead 13 amp single socket on the male end .

 

[dave h 2]

This lathe is as big as a two slot toaster. They used to be treadle operated.
You could try a brushed 775 size motor at just under 100W.

 

[Newlands]

Thanks for the replies. Decided to go for a servo motor, as they are fairly cheap from China, brushless, variable speed and will plug into the mains.