Pfaff 335-17Bl

[dikman]

I decided that the smallish pulley (3") on the handwheel really had to go! So after a bit of messing around on the lathe with one of the alloy pulleys that seem to be commonly available for sewing machines (in this case a 4 1/4") I managed to get a bigger working pulley to fit on the handwheel. This made quite a difference, although still not up to the control of a servo, of course. This gives me a ratio of 2.5:1, (the original must have been close to 1:1) and I reckon that if I couple this to a servo I should have excellent slow speed control.

Edited October 6, 2015 by dikman

[dikman]

Uwe, thanks for those part numbers, I managed to source the two feet locally (generic,about Aus$28 each, but the guy said I wouldn't want to know the Pfaff price!) but they couldn't help with the feed dog/needle plate. As you suggested, I contacted Kwok Hing directly and they said they would send me an invoice (shipping is dearer than the parts!). I have a feeling that with these parts, and once I get the speed under control, this is going to be a very nice machine to use.

[dikman]

The mailman dropped my Kwok Hing needle plate and feed dog off today. The feed dog didn't quite fit (!), but a bit of work on the belt grinder fixed that. I had already mounted a servo to it, and coupled with an 8" pulley on the head it crawls along nicely. I ran a piece of 1/4" leather through it and it punched the holes without any effort, so figured I'd better try some stitching. I loaded some #69 white thread on the bobbin and ran some brown #69 through the needle. The machine came with a size 21 fabric needle, as it had been used, with #69 thread, for binding some sort of nylon/cordura material so I just used that needle. Max stitch length, one layer of 9 oz veg and the stitches looked great. I shortened the stitch length and ran it through and again it looked good. Next thing was to double the thickness - and this was where I came undone! The second scrap piece I used tapered down to a narrow end, it started stitching well and then "twang", one busted needle! (I'm getting quite good at breaking needles).

The problem was, I think, that I got too close to the edge and the lack of support, combined with me feeding the leather pushed the needle slightly out of alignment. No big deal, though, as until it broke it was sewing well. It went through 5/16" of leather as though it wasn't there and the stitches looked pretty good too. Reverse feed also worked fine, putting the needle right into each hole. This looks like it's going to be a very nice machine to use, and I'm feeling pretty good about my purchase.

Earlier I had referred to it as a compound feed, but I guess because it has a smooth feed dog that really makes it a needle feed?

[DrmCa]

Where did you get 8" pulley for the head?

I think you are pushing it with 2x9oz.

[dikman]

The pulley is from one of my "bits and pieces" boxes - the one for pulleys and bearings. As to where it originally came from, I've got no idea! It's fairly heavy cast steel, so gives a bit of a flywheel effect. When I removed the existing pulley/handwheel it left a 1/2" shaft, which just happened to be the size of this pulley (I have a nice alloy one that I intended to use - same size - but it has a large centre hole and I would have to make a sleeve for it. This seemed easier). Might look a bit odd, but it works.

As for pushing the limits size-wise with the leather, yep, I'm under no illusions about what I'll be able to do with the machine. It's more a matter of experimenting to find its limits. It has no problems pushing a needle through the thick stuff, but actually sewing a stitch may be a different matter. If I can use 138 thread through slightly thinner stuff then I'll be happy with that.

[DrmCa]

That's a monster of a pulley! I want something similar, but light - in Aluminum. Maybe casting my own.

[Uwe]

Love me a good hack! It seems like a viable alternative to pricey speed reducers which I can't bring myself to spend $130+ on.

Amazon has nice 1/2-inch bore 8-inch OD TB Woods cast iron pulleys for around $50 shipped to provide a bit of flywheel punching oomph or lighter aluminum pulleys for around $30. I've used TB Woods pulley on a few occasions before and they're very nice quality and nicely finished.

My Consew 225 has a 1/2 inch shaft and just over 3" pulley on the hand wheel. An 8-inch pulley would slow things down significantly. With a nice powder coat finish, even the aluminum one might look pretty enough to not be embarrassed about it. I'm so tempted to give this a try. Can't really think of a reason not to.

[dikman]

The beauty of this is that there's no hassles trying to mount a speed reducer and line up the belts. The servo motor's pulley is less than 2", so this combo gives me lots of low end grunt. So far the Pfaff seems to love it. I figure if it's good enough for some of the bigger machines to have a large pulley, it's good enough for the little Pfaff! All it cost me was $12 for a bigger belt.

I just wish I could do the same to the Singer 166, but I can't, so I'm in the process of making a speed reducer (I'm scratching my head trying to figure out how to mount it).

[Uwe]

The simplicity of this approach is compelling indeed. This ebay seller has a nice selection of zink die cast pulleys all in one place in his listing: http://r.ebay.com/qtGSU9

Edited October 24, 2015 by Uwe

[dikman]

Nice choice of pulleys, unfortunately for me the price of shipping ($85!!!) is a minor problem. The largest I found out of China is a 120mm (free shipping), so I figured mounting that on a shaft with a 45 mm should give me some speed reduction and coupled with a servo with another 45 mm on it will give the Singer a bit more low end grunt. It's not too bad now, but it won't do any harm to fit the reducer.