brushless DC motor for mini lathe

[John HaineParticipant @johnhaine32865]

Looks like a watchmaking or instrument lathe. Needs a good headstock chuck and maybe collets.

[Clive SteerParticipant @clivesteer55943]

John. If you want to use a VFD you would need to buy that and a matching 3 phase motor plus some sort of control box (pendant) which has the forward/off/reverse selector switch and speed setting pot.

A BLDC sewing machine motor kit comes with motor mounting components, motor controller unit similar to a VFD and a manual control box.

The downside is that the unit doesn't have an easy way to select reverse as the direction of rotation is a set up parameter. As mentioned before the controller has 3 operating regimes, Off, a fixed preset slow speed and a variable speed preset range. You will also need to make/acquire a motor pulley to match the belt size your lathe uses.

CS

[John RutzenParticipant @johnrutzen76569]

Clive, please can you tell me if you solved the problem of getting the variable speed range? Did you add a potentiometer?

[Clive SteerParticipant @clivesteer55943]

John.

I did for the Jack controller using a 3 turn potentiometer and an on/off switch to effectively short out the speed set signal. A 3 position switch can be used, plus a few resistors, to give OFF, Preset SLOW SPEED (jog) and then on to full variable speed. My Jack motor system is fitted to my Pultra lathe and works very well.

CS

[John RutzenParticipant @johnrutzen76569]

Clive, thanks, I've just ordered one from Tysew in the UK for £99.99 including post. Please could you send me a picture of yours or a diagram, I'm not sure how it works from the description. I'd just thought of putting a knob on the metal lever and mounting it on the front of the bench. Lathe work is one handed anyway so you could use it as a sort of dead man's handle as is Electric Railway Locomotives.

[Rod RenshawParticipant @rodrenshaw28584]

+1 for interest in Clive's setup. I bought one of these moters (a "Jack&quot in 2021 after reading this thread (or another similar one.) The motor is small and smooth etc but I was puzzled by the control system and I put the motor on one side due to other distractions. So my Pultra is still unmotorised.

Rod

[Clive SteerParticipant @clivesteer55943]

If you look at my photos you'll find 4 related to the fixing of the Jack motor and control box to my Pultra. My arrangement is fairly complex as I wanted the lathe and drive to be "portable" so I can pick it up as one lump and move it from bench to bench. Also the motor is mounted close to the lathe so it doesn't need a great depth of bench space. I'll add a picture of my pendant circuit but you can just take the return spring off the supplied controller, that's designed to provide foot control, extend the lever and some friction device to provide hand control.

CS

[Clock polisherParticipant @clockpolisher]

Good evening,

I fitted a 550w Husuper sewing machine servo motor to my Unimat SL lathe many months ago.

I use it practically every day and have nothing but praise for it.

It was effortless to fit and set up straight out of the box. It is very quiet and reversible at the touch of a button.

I use either of the pulleys that came with it, with different belts, to give two broad speed ranges. I have it mounted on one bolt so I can adjust belt tension easily, like an alternator on a car.

I set a maximum speed on the digital controller and control the actual lathe speed with the supplied Hall effect sensor lever, set up for left-hand control rather than foot control. I've put the hand control in such a position that I can flick it off in a hurry if any problems develop.

David

[John RutzenParticipant @johnrutzen76569]

Thanks for the info. I've looked at your photos now Clive and like the very compact arrangement, I need to do something similar because I've very little room available where I am putting the lathe. Good to hear that you have had good results too David.

[John RutzenParticipant @johnrutzen76569]

Hi Clive, I've got the motor now but I have a problem I can't see the way around. The braking effect is very noticeable and I am wondering what will happen with a chuck on the lathe. I can imagine is flying off spectacularly! I haven't found a way round this. Any input please?

[Clive SteerParticipant @clivesteer55943]

Hi John

I ca't see how the chuck is fitted on your lathe. However for many lathes with screw on chucks an extra clamp is fitted to the spindle and links to the chuck. I had one on my Boxford lathe but can't remember exactly how it was done but I'm sure there may be other who can provide details. Having said that your lathe looks like an instrument makers lathe so probably would have mainly used collets. Another possible way is to fit a ratchet system to the drive pulley, similar to the freewheel fitted to bicycles, so when the motor stops the chuck can continue to "freewheel". Thee downside is you can't use reverse. Not ideal but if push comes to shove.

CS

[John RutzenParticipant @johnrutzen76569]

Hi Clive, yes it's a screw on chuck. Funnily enough I had just thought of the freewheel as well, you can get them on ebay for about £8 made for electric bikes so they are quite robust and only have a 12T sprocket on them. There is room for a pulley so I would have to make up a little countershaft. I had thought of doing that anyway because I would like about a 200 rpm bottom speed. The pulley on the motor seems to incorporate the fan though I can't see how it would do much cooling. It has slots around the centre and radial blades cast in so it is quite a large pulley, about 55mm diameter. Does your motor run cool? The brushless dc motor on my mill always runs cool, even working hard.

[Clive SteerParticipant @clivesteer55943]

John. Sewing machines can have very high operation duty cycles and run at high power and since the motor is located under the work bench it may not have the best ventilation so hence the fan. However for our type of use the headstock bearings will probably get hotter than the motor and I've not noticed mine getting hot. On my Jack motor, which is a JK-513A, the fan is the other end of the motor to the pulley.

CS

[Clock polisherParticipant @clockpolisher]

Good afternoon John,

With regards to your question about breaking efficiency and screw-on chucks.

I have a Unimat SL with this type of chuck and when testing the new motor I very casually stopped it from 4500 rpm and I got the chuck on my knee, at speed.

The breaking efficiency is, on my motor, a user defined parameter within the controller. It comes set at maximum as a default. Presumably to avoid sewing machine operators sewing more than two of their fingers together before it stops.

I reduced this setting to zero from 3 and the motor now coasts to a stop gently in a few revolutions.

I included a set of photographs of the parameter sheets for my motor in my album.

David

[John RutzenParticipant @johnrutzen76569]

Hi David, thank you, unfortunately my motor isn't the same. The buttons are different and there is no adjustable parameter for the braking effect. I am drawing up a countershaft unit incorporating a freewheel. I don't need reverse since I won't be cutting any threads and there is no rear toolpost.

[Clive SteerParticipant @clivesteer55943]

I'll have to check the Jack controller to see if it has any "hidden" parameters that aren't described in the rather brief user manual. In my investigation of Sewing machine motors I did get two different types. A Tysew (Jack 513A) and a Tansew (TH-550S-2) which looks similar the Husuper one that David has and has the same parameter list in the user manual. I was looking to modify the code to get rid of the low speed (jog) feature and the Jack controller uses a similar processor to that used on Arduino making the task easier!!!!!

CS

[Andrew EntwistleParticipant @andrewentwistle]

I just received a sewing machine 550W brushless servo motor and controller from VEVOR £65.99 including free 2-day delivery.

VEVOR 550W BRUSHLESS SERVO

Came with an A4 sheet manual which can also be downloaded as a pdf file via the QR code on the motor. I set it to 100 rpm minimum and 5000 rpm maximum with braking turned off and it runs amazingly quietly throughout. Torque at 100 rpm is enough that it is impossible to stall by gripping the pulley. I will replace the potentiometer intended for pedal control with a rotary pot.

Andrew.

Edited By Andrew Entwistle on 07/09/2022 22:23:50

[Ady1Participant @ady1]

I just got the 750w 1HP version as an experiment and stuck it on the back of my Drummond, bolted onto the top of my Higgs "guaranteed forever" motor

Works great but I wouldn't use it for too long on a proper semi-industrial lathe

Will end up using it for either light milling or as my main Cowells unit

A very simple reliable system at a nice price

Edit, I recommend using the 50mm wheel, swap out the 75mm

A 24mm holds the belt wheel and a 19mm undoes the nut, it taps off the key by hand, don't let the key drop out

If you need the motor to reverse, hold down the S key until the little light comes on in the bottom right corner of the main display

Edited By Ady1 on 07/09/2022 23:46:54

[DellParticipant @dell]

I know this is an old thread but if anyone needs a wiring diagram to convert a jack industrial sewing machine motor to a potentiometer including what resistors and pot to use I have it, I fitted one on my Pultra 17/70 under the bench and it was the best thing I did torque amazing even very slow, I even used the cast box to put the pot in just make sure it and everything is earthed.

Dell

[Ian PParticipant @ianp]

Posted by Dell on 10/07/2023 19:50:25:

I know this is an old thread but if anyone needs a wiring diagram to convert a jack industrial sewing machine motor to a potentiometer including what resistors and pot to use I have it, I fitted one on my Pultra 17/70 under the bench and it was the best thing I did torque amazing even very slow, I even used the cast box to put the pot in just make sure it and everything is earthed.

Dell

I know it been mentioned before in this thread but the Hall device (and any potentiometer that is wired in its place) is NOT ISOLATED from the incoming mains supply so installing in a grounded metal enclosure make sense.

If using a plastic enclosure its best if the potentiometer has a plastic shaft too, also any wiring to the potentiometer should be treated as if it was carrying mains voltage.

Ian P

Edited By Ian P on 10/07/2023 20:35:32

[Michael Starling 1Participant @michaelstarling1]

Hi Dell, I would be very interested in in your diagram for converting a sewing machine motor to a potentiometer.

Thanks!

Mike

[modeng2000Participant @modeng2000]

Dell, I also am interested in modifying the hall control to a pot.

I expect there are several others out there as well.

Regards, John

[John RutzenParticipant @johnrutzen76569]

I took the spring off my motor switch and put a plastic knob on it. I also put a friction pad on the arm to prevent accidental operation. I now have it mounted above the lathe and find it really convenient to operate.

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