dikman

I agree. While it can be done the question is why bother? Servos provide a much neater, relatively inexpensive solution.

Hmm, being an electrician I would have thought you'd be aware that VFD's are used with 3-phase motors, all the clutch motors I've come across have been single phase. Toxo is right.

No, it shouldn't hit the needle! The timing looks like it's out. The hook should be aligned with the scarf (recess) in the needle., the needle bar is too high.

Sad. Another one gone too soon.

That's a nice approach, fairly simple and makes for easy adjustment.

Yep, horses for courses, as they say. Hmmm, soft start on a domestic machine?

I agree with Gymnast. You refer to them as hobby saws. Maybe, but by definition they are a table saw (a table with a saw mounted in it), there is no rule that states a table saw must be large and have an induction motor. And these smaller table saws inevitably have universal motors, which lend themselves to easy speed control.

That's for 3-phase motors. If that youtube video is working on a single phase induction motor I'm curious how it does it. The instructions with my VFD's give connection details for using with single phase induction motors to vary their speed. I thought this would be great for my grinder but I did some research and yes, it will work BUT it isn't recommended! The motor won't develop much torque and it may overheat. Hence the need to go to 3-phase motors. I just finished digging around for more soft-start info and Don's post about the Baldor unit is the key. That unit is intended to work on single-phase induction motors and the link explains how. The one that Constabulary linked to is doubtless the same type of unit, so I've learned something new. The Baldor information indicates that the soft-start unit needs to be matched to the power rating of the motor, so buying one at random could be a problem.

Keep up the good work, Don, you're finding out all sorts of things and saving us the trouble.

I think the last two posts have summed things up pretty well. Rosch22, that price is certainly very good (too good?) and I can see why you're interested but I think I would be very cautious about the offer. I honestly don't see how they could deliver a head unit to your door in Germany at that price. So I think you should do it, then we'll all know if it's a real deal.

I thought the "soft-start" modules were designed to work with universal brush-type motors? Squirrel cage induction motors are notoriously difficult to use with any form of speed control, which is why people change their lathes, belt grinders etc to 3-phase motors + VFD.

There are clones and then there are clones. While they might all seem the same on the surface there could be some variation in quality of parts and how they're assembled. It would also want to be very cheap, imo, because as mentioned the hidden costs can be a killer! I went down the path of looking at importing one directly (to Australia, and we're not that far from China) but by the time I had looked at all the other costs there were no savings to be made. I contacted numerous companies and while there were a couple of follow up queries from some there was no "pestering". Unless you can get a delivered quote, as previously mentioned, I would be cautious.

Hi Melrose, I don't suppose you happen to be in Melrose, in SA? Or is the name just co-incidence? Yep, get rid of all the machinery underneath the table! Small pulleys (45mm) can be bought off ebay, as can speed reducers, although they might have to come from China. Another possibility is to replace the handwheel with a large pulley, which will give the same effect as a reducer. Some don't like it because it doesn't "look" right. If the table is basically in good condition I'd clean it using steel wool, which should retain some of the patina, and give it a coat of varnish. MY 2c worth.

Stop thinking so much, Constabulary, you'll give yourself a headache!

Good luck with that! A sewing machine specialist place would probably know if their particular motors would work, but I doubt if many vendors who sell these generic servos would even know what a speed reducer is!!

I stand (or at the moment sit) corrected then. I based my statement on my experiences and those knob-control brush-type servos aren't common here in Oz whereas the generic brushless are everywhere! When you can find a knob-control unit they are expensive!

Yes, pretty well all of the generic servos out of China are brushless and have been for a few years. That Sailrite servo is a nice compact all-in-one unit BUT if you mount it under the table you will have to get down on your knees and scrabble around under the table every time you want to make any adjustments to the controller.

If you intend motorising it then why bother with the handwheel? It already has a pulley fitted.

That is quite an impressive piece of mechnical wizardry! That original needle looks like it was designed to sew several layers of plywood!!!

Pretty well sums it up, I think.

$120?? Can you provide a link so we know which machine you are referring to? And what do you want to sew?

Bow, both machines, to all intents and purposes, are the same. As Northmount said finding a local (closest) dealer is probably the thing you should be looking at to give you support if needed.

The older model 335 has approx. 8mm under the foot, I believe the newer model has a bit more. It sounds like you should be looking for a machine that has at least 12mm under the foot.

A servo is definitely the way to go, as kgg said try it as is first and if it still doesn't give you the control you want then add a speed reducer. I found a needle positioner wasn't really much use for my style of sewing (slow!) as I can control the needle without one, plus some of them don't work when a speed reducer is fitted.

I haven't used them a lot but no problems when I did.