Will The $150 Chinese Servo Motors From Ebay Work On An Old Adler 68?

[Vinculus]

Haha, I was wondering where I would get the alu to make the shim. That's brilliant.

[TinkerTailor]

Haha, I was wondering where I would get the alu to make the shim. That's brilliant.

Sometimes you have to try a few brands to get just the right thickness of can......

I find japanese beers and weird soft drinks at asian food stores often come with thicker cans

Edited December 11, 2015 by TinkerTailor

[Vinculus]

I thought I'd give everyone an update on how all of this went:

Giving up on getting a custom 40 mm. pulley made, since I was quoted €150 for it, I went another route.

I ordered a 40 mm. 15 mm. straight bore pulley from College Sewing, thinking I could simply make a shim to make the fit around the motor shaft acceptable.

Turns out the bore portion of the pulleys sold by CS are about twice as wide as the stock JK-510A motor pulley. This meant the motor pulley shaft was not long enough for the new pulley to fit.

Solution: I took a hacksaw to the protruding end of the new 40 mm. pulley and simply sawed it off, leaving it narrow enough for the motor shaft to reach all the way through the pulley bore. I made sure to file it all level afterwards where the hacksaw left unevenness, so the pulley would not spin off-center because of surfaces not being flush with each other.

Then a new problem arose. I couldn't simply attach the narrowed down 40 mm. pulley to the shaft because 1) it has a 15 mm. bore as opposed to the 13 mm. motor shaft, and as such it would only tighten all the way down to the motor body and simply get stuck flush with the motor casing; unable to rotate. Luckily, it appears the motor shaft has been turned down to 13 mm. from 15 mm., so there is a small portion of the shaft closest to the motor that still has a diameter of 15 mm.

From here the solution was simple: I took a DIN125 round washer (14 mm. inner diameter) and slid it onto the motor shaft, so that it rested upon the 15 mm. innermost portion of the shaft, leaving the necessary space between the pulley and motor case for everything to spin freely. All that was left after this was making a beer can shim to get the 13 mm. motor shaft to accommodate to the 15 mm. pulley bore.

The machine now sews at a very manageable slow speed and I am very happy with the final outcome of this project.

In conclusion, however: I would not recommend getting a Jack JK-510 servo motor if you want slow speeds without an external speed reducer. Replacing the original pulley requires far more work than it should. Typically it would be a 10 minute job. In this case it took hours and a lot of improvisation for a result that is still not optimal; but rather works okay.

[TinkerTailor]

Great to hear.

[banjo48]

I've got a Seiko STH 8BL sewing machine with clutch motor, which I sew mainly heavy canvas and shade sail cloth, was thinking of buying one of these Jack servo motors in the 1hp variety, to a) slow it down for detailed work, and save some power usage if possible.

Now reading this I'm unsure, I don't mind the pulley mod too much as I have access to an engineers shop so could easily sort a smaller pulley out.

My main concern is, is just the smaller pulley and the basic servo slow enough without going to the reducer set up ? or would I need both ?

What would the slowest speed be with the servo and just the pulley reduction ? approx rpm ? I don't do high speed sewing as I try to get perfect stitch lines if possible like you leather work guys.

Love the forum by the way, lots of good info.

[dikman]

Banjo, I've fitted three servos to my machines, 2x550w and 1x750w. While I ordered them online via Ali-express (Chinese ebay), the company has a warehouse in NSW so delivery is within Australia, not from China. Only drawback is they come with 75mm pulleys, but I requested a smaller one and they sent me, at no charge, 45mm pulleys from China. The shaft and pulleys are 15mm, which as Darren mentioned elsewhere is pretty standard on Chinese motors and pulleys.

On one of my machines, a Pfaff 335, I fitted a large 8" pulley in place of the handwheel and with this combination I can walk this very slowly. On a recent belt I made I used it to follow pencilled guide lines to stitch a pattern in the belt. It was actually quite nerve-wracking, as I hadn't tried doing this before. The "standard" range of pulleys that appear to be sold for sewing machines (on Ali-express/ebay) appear to only go up to 120mm, so I had to adapt a larger one that I had in my spares box.

And yes, this is probably the best place around for info/help/advice on industrial sewing machines.

[banjo48]

dikman

Thanks mate, do you have a link to the Ali-express supplier ? probably easier than shipping from the UK. and cheaper freight.

[Vinculus]

For reference, I recorded a quick video to show the absolute slowest I can go with the Jack motor fitted with a 40 mm. pulley.

Sometimes I wish I could go even slower, but it's entirely possible to work the foot pedal to do one stitch at the time. I find that's better than rotating the balance wheel manually when sewing around tight corners, as the SPI somehow tends to not match up with the rest when hand cranking the machine.

[banjo48]

Vinculus

As they say a picture is worth a thousand words ! that speed would be fine for my requirements, so that's just the Jack motor with the 40mm pulley, just to clarify. No reducer ?

[Vinculus]

That is correct! You can always crawl at this minimum speed no matter what you have the maximum speed set to as well, which is nice. Don't know if it's the same with other motors.