Bert Coules

Izzy, that's a good point about the heat dispersion, thanks. So far, lacking the pulley, I've only run the motor for short bursts in order to test everything, but in actual use I expect things to be rather different. The speed control works beautifully and over a wide range. Incidentally, my speed controller has an on/off switch at the start of the rotary control. For my tests I've been using that to stop and start the motor rather than adding a separate switch, but I don't know about its long-term reliability. One thing which did strike me was that I had to reverse the connections to the motor to get it to rotate in the necessary direction: clearly its usual setup in a scooter requires it to revolve anti-clockwise.

I now have the new motor up and attached and running, The lathe isn't working, since I've yet to get the motor drive pulley, but that's not going to stop me being pleased with progress so far. I don't know if anyone else found this, but for me the hardest part by far was reassembling the motor after adapting the spindle end plate for bolting to the Unimat. Keeping the brushes in place while re-inserting the bare motor into the housing really needed three hands - and the fact that when the magnets catch hold the motor shoots into the case like a nuclear-powered guided missile didn't help (and my word, that gave me a [non-electrical] shock the first time it happened). And then you have to be sure that both of the end plates are properly aligned, and fiddle about getting the long bolts into their threaded homes while they're constantly pulled off course by the magnets in the case. But it's done now. Many thanks to everyone here for all the help and advice. Bert

As a follow-up to my switch query, I've been advised by an electrican to route the power as follows: mains > switch (located near the lathe and used for switching it on and off operationally) > PSU > speed controller > motor This seems to run counter to the advice I've seen elsewhere to avoid switching the PSU on and off too frequently. I'd be grateful for any thoughts.

I now have the motor, the speed controller, and the PSU. A question about the type of switch I need for the 24V DC feed to the lathe: is it sufficient to insert a switch across just the positive output from the PSU and take the negative output direct to the speed controller? Many thanks.

That makes excellent sense.

I bought the power supply I linked to earlier: ordered on eBay on Saturday, delivered today (Monday): excellent service from the seller. It is fan-cooled, with the fan set to kick in when the unit reaches 45 degrees C. Izzy, I'm undecided about an overall housing but whether I go down that route or not I'll certainly follow your example and arrange something to tether the input and output wiring: I don't want to trust solely to those screw terminals. I await the motor and the speed controller...

Izzy, thanks for that. As I said, my natural instinct was to put the speed controller between the switch and the lathe: it's good to have that confirmed as the best practice. I also like the idea of an LED indicator to show when the switch is on in case the lathe is powered up but not rotating - I believe I've seen switches with built-in illumination which would be a neat way of achieving this. I didn't know that it's considered desirable not to switch the PSU on and off too frequently, so I'm grateful to have learned that.

Izzy, that's really helpful, thanks. And a very neat bit of construction. I want to incorporate an on/off control as close to the lathe as possible for operational convenience and safety, which means putting a switch into the 24V cable: the PSU will be fed from a conventional switched mains wall socket but obviously I don't want to use that to control the lathe. I presume that your lathe has a switch built-in but the Unimat is rather more basic. I'll also be including an electronic speed control, which presumably is best placed after the DC switch.

Thanks for that. I found this unit on eBay which seems to fit the bill. I like the idea of enclosing it (with ventilation) though, not just for protection but also perhaps to arrange a proper socket for the incoming mains connection.

As the owner of a Unimat SL which lacks a motor I was delighted to find this discussion. I found on eBay what seems to be the exact motor used by Richard Jones available from a UK seller, but the PSUs I've seen all appear to come from suppliers in China. I've no objection to buying from there beyond the long delivery times, but if anyone can point me to a UK source, I'd be very grateful. Many thanks.