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

[Vinculus]

Oh, I thoght there were all kinds of diameters like 8,5 mm, 9,3 mm, 10 mm, several tapered bores, all kinds of inch fractions. You probably got lucky.

When I asked Colege Sewing about exchange pulleys they said, there were none. I should change the speed settings.

Greets

Ralf C.

College Sewing told me the same, and even added that the stock pulley is "fixed". This is obviously not true, since it's fastened with a regular nut and washer.

Anyway, after searching this forum, I found that the Jack motors have a 13 mm. straight bore shaft. This is some kind of stupid non-standard size, so it looks like I'll have to have 40 mm. pulley custom made.

I am wondering, however, if a 15 mm. straight bore could work. The pulley has a notch and the shaft should have the key for this notch, so it's not like a 15 mm. bore pulley will spin around freely. What do you guys think? The pulley might rotate 2 mm. off-center, but otherwise it should work, no?

I'll probably have a 40 mm. pulley custom made anyway. At 200 rpm, which is the crawling speed of the motor, it's still too fast for the delicate and non-linear work shoes require. Should probably think about building a speed reducer as well.

[dikman]

My first thought was "they don't know what they're talking about!" Unless they had that motor specifically made for them (unlikely, as it's similar to several other brands for sale on AliExpress) then the shaft will be 15 mm. I also have two generic clutch motors, both a few years old, and both have 15 mm shafts. Like I said, the guy at the shop (who has been in business a long time) said that 15 mm is pretty much a standard shaft size for industrial-type sewing machine motors.

Don't take their word for it, remove the pulley and measure the shaft, that way we'll both know.

[Vinculus]

Well, it wasn't easy, but I got the stock pulley off. It does indeed appear to be some kind of non-standard size and configuration. The shaft is 13 mm, bummer.

What is really weird is how the key for the pulley bore is a separate piece of metal that was just jammed in there. I was under the assumption it would be part of the actual shaft. Is this normal? See attached pictures.

Looks like I'll have to get a custom pulley made. Sucks!

[Kohlrausch]

In Germany I find 12 mm and 14 mm bores, no 13 mm. I'ld try a 12 mm and a 13 mm drill. Or a 14 and a little bit of sheet metal to fold around the shaft.

Greets

Ralf C.

I found that the Jack motors have a 13 mm. straight bore shaft.

I am wondering, however, if a 15 mm. straight bore could work. The pulley has a notch and the shaft should have the key for this notch, so it's not like a 15 mm. bore pulley will spin around freely. What do you guys think? The pulley might rotate 2 mm. off-center, but otherwise it should work, no?

[Kohlrausch]

My first thought was "they don't know what they're talking about!" Unless they had that motor specifically made for them (unlikely, as it's similar to several other brands for sale on AliExpress) then the shaft will be 15 mm. I also have two generic clutch motors, both a few years old, and both have 15 mm shafts. Like I said, the guy at the shop (who has been in business a long time) said that 15 mm is pretty much a standard shaft size for industrial-type sewing machine motors.

Don't take their word for it, remove the pulley and measure the shaft, that way we'll both know.

At this very moment I have pulley with three different tapered bores lying around me and motors with three different cylindrical shafts. There certainly are a lot more possibilities than 15 mm. Wish it were that easy...

Greets

Ralf C.

[Vinculus]

In Germany I find 12 mm and 14 mm bores, no 13 mm. I'ld try a 12 mm and a 13 mm drill. Or a 14 and a little bit of sheet metal to fold around the shaft.

Greets

Ralf C.

I found that the Jack motors have a 13 mm. straight bore shaft.

I am wondering, however, if a 15 mm. straight bore could work. The pulley has a notch and the shaft should have the key for this notch, so it's not like a 15 mm. bore pulley will spin around freely. What do you guys think? The pulley might rotate 2 mm. off-center, but otherwise it should work, no?

Could you give me a link to where I can get a 12 or 14 mm. bore pulley?

[Kohlrausch]

Could you give me a link to where I can get a 12 or 14 mm. bore pulley?

http://keilriemen24.eu/index.php/cat/c12295_1008-1008.html

http://www.wdn.de/artsearchresult.php?STICHWORT=riemenscheibe+40&x=0&y=0

http://www.mercateo.com/p/102-238341%282d%29BP/Keilriemenscheibe_aus_Aluminium.html

Seems you can only get 50 mm diameter with taperlocks.

HTH

Greets

Ralf C.

[Vinculus]

Oh well, custom made it is, then.

It'll work itself out eventually I guess.

[dikman]

I must admit that I'm surprised that it's not 15 mm (particularly as it appears to be your basic Chinese servo). We live and learn. The keyway is pretty standard, and is the same on all my Chinese-bought pulleys, plus the locally bought ones (same thing) and also the two generic clutch motor pulleys. As there's only 2 mm difference, you could try some thin sheet tin or aluminium to sleeve the shaft, cutting a slot for the key. If you can get a snug fit then it should be pretty close to centred and tightening the nut should lock it in place. Considering that you don't intend running at high speed it should work fine.

[TinkerTailor]

If you look at the picture, that shaft coming out of the motor is about 2mm wider and then steps down. I think they turned then down for some reason, perhaps due to poor original finish or to use up a bunch of pullys with incorrect center holes with the keyways already cut..

[dikman]

Well spotted, I didn't see that. Guess we'll never really know why it was done.

[Darren Brosowski]

????

The motors originally asked about in this thread use a 15MM bore with 6mm key.

China tends to use one standard and they do not do low volume specials

[Vinculus]

????

The motors originally asked about in this thread use a 15MM bore with 6mm key.

China tends to use one standard and they do not do low volume specials

Yeah, but I didn't end up buying the motor in the first post. Instead I got a Jack JK-513A from College Sewing. Turns out it has a non-standard bore, as seen in the attached picture. I will probably try dikman's suggestion and buy a 15mm bore pulley and wrapping some sheet aluminium around the motor shaft; at least before investing in a custom made pulley.

[Kohlrausch]

????

The motors originally asked about in this thread use a 15MM bore with 6mm key.

China tends to use one standard and they do not do low volume specials

Darren,

do you know how slow the motors of the first post can turn?

Greets

Ralf C.

[TinkerTailor]

Yeah, but I didn't end up buying the motor in the first post. Instead I got a Jack JK-513A from College Sewing. Turns out it has a non-standard bore, as seen in the attached picture. I will probably try dikman's suggestion and buy a 15mm bore pulley and wrapping some sheet aluminium around the motor shaft; at least before investing in a custom made pulley.

Hard to see in this photo, is the hole in the pulley 1/2 inch exactly? If so, a farm supply store, or mcmaster-carr will have a pulley for you. 1/2 inch is really common outside sewing machines.

In the bicycle world, the is technical term for this process is a beer can shim. Been keeping seatposts up since '78....

Edited December 11, 2015 by TinkerTailor

[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.