Speed Reducer And Servo Motor?

[dikman]

As toxo mentioned if you replace the handwheel with a larger pulley that, coupled with a smaller motor pulley, will give you the equivalent of fitting a speed reducer. And it's simpler. I've done it on several machines.

[Wellington]

Thanks again, Dikman. I might try that. I'd assumed that the pulley and handwheel were one unit that couldn't be separated. Even if that's the case, I guess I could just use the pulley itself as a handwheel, but if it's possible, I'd prefer to take out the existing pulley, replace it with a larger pulley, and then replace the original handwheel. Walking foot hot rodding! 

[dikman]

Sorry mate, every handwheel I've seen has been permanently attached to the pulley! The shaft won't be long enough to attach another pulley as well as the handwheel.

[Wellington]

Here's what I came up with. I tripled the effective length of the "throttle lever" on the servo motor by attaching a ~ 10" piece of aluminum tubing to it (tubing nearly flattened with a vise at ends before drilling).

By lengthening this throttle lever, and putting a smaller drive sheave on the motor, and jamming a tennis ball (to act as a compression spring) under the back of the throttle pedal, I can set the motor speed to full speed, and still feather it to go slow with my foot. And if I want "full speed," I can mash down on the pedal and get it, without changing the dial position on the motor. (The other half of the answer, I think, is refining the fine motor skills in my leg and foot. I've always preferred knee throttle levers to work around this clumsiness. I hope I don't get turned around switching back and forth between machines but really look forward to having a knee presser lifter, and will probably copy it to retro-fit a knee presser lifter to my Pfaff 130...some of them came from the factory that way, but trying to find the lever part is a losing propositon.)

Don't know whether this kludge will have the torque/punch for heavy leather, but it should work for my purposes sewing light leather and heavy fabrics, I think. 

Thanks again for everyone's help. This is a great website...it seems that every time I have another question about my new walking foot machine, Google leads me here (for example, I just found Wizcraft's simple solution for stopping bobbins from slipping on the bobbin winder shaft...thank you Wizcrafts!).

W. 

 

Edited November 10, 2019 by Wellington

[Bert51]

I have found that if you have your belt tension to tight, it will make it stiff to move the peddle.

I slacken the belt so it is just tight enough to turn the pulley without slipping, will help. A new grippy belt works a lot better then an old hard belt.

Bert.