Okay, back story, I had a Willcox & Gibbs Automatic (chainstitch) like many, that had no drive mechanism. Actually, it's a New Home, same difference. And then I got what I thought wasn't too bad of a deal on a W & G with a motor, but no foot pedal. Well the motor wasn't just missing one brush and its threaded plastic retainer, the casting that it threads into is mostly broken out, so I'm going to have to find a W & G motor (Westinghouse) that I can either get parts from or just use it.
So what about the Hand Crank?? drum rolllll......
Ta dah!
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this is sort of a mockup, test of concept, kind of thing. Another view..
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Actually my first trial was to put 2 screws thru the wooden disc, into threaded nylon posts, to go into the drive wheel, directly like the motor would. However, alignment might be a little fussy, and if it's off even a little it will add vibration. So, what we have here, is kind of a universal test jig, or, you could actually sew with it. For any youngsters out there, who might not understand what you're seeing, it's a hand crank grinder, sharpener. These things turn up relatively often in the same kind of places that old sewing machines do. Online auctions, garage sales, antique stores, etc, but I can't recall the last time I saw one in a thrift store. If you want to try this, I'd suggest finding one that has a stone less than 4" diameter, a 5 or 6" stone capacity is too heavy and large. This one has a gear reduction that gives a 9.5 turns ratio, so for each turn of the crank you get 9.5 rotations of the machine balance wheel. I think that hand crank sewing machines often turn around 5:1, which is easier on your arm.
My initial idea was to wear a groove in the grind stone, to drive a belt. I have a lathe, but there are other ways to come up with a wooden disc, a hole saw in a drill press, careful sawing, sanding and filing, or,...you could actually take a roughed out piece of wood and turn it down using the grinder as a lathe, and it's tool rest, to steady your cutting tool, then cut a groove, sand and spin it while wiping in some danish oil or?
If I use it on a base for a different, more conventional style of machine, it will have a larger balance wheel than the W&G, which will make it easier to turn but slower. There are a number of options for mounting, it could be in front of the W&G, or below another type machine's balance wheel, since it clamps on, you can adjust the belt tightness. More later...