Author Topic: Sewing Machine Modifications  (Read 1993 times)

Offline S. Heslop

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Re: Sewing Machine Modifications
« Reply #25 on: April 08, 2019, 05:08:53 PM »

Also am I right to assume that any bipolar stepper motor driver with the right current & voltage rating would run any bipolar stepper motor? I've got a bunch of drivers hanging about. Lyn sent me a few and i've got some A4988s from the 3d printer adventure.

This spreadsheet may be of some use.

Thanks!


Here's a blurry photo.



It's been slow going so far, getting distracted with other duties. Need to put some holes into the arm then weld that into the column. Still thinking about if it'd be better to weld the column to the base or to try fix it with bolts. Jumped the gun a bit on welding the column pieces, but I wanted to weld something...

Offline S. Heslop

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Re: Sewing Machine Modifications
« Reply #26 on: April 19, 2019, 05:22:43 PM »
Still puttering away at this as time permits. Decided to ditch the electronic zig-zag idea since i'm not sure if it'd work. Spent today measuring up all the important zig-zag stuff from the donor machine.


 
Plan is to just turn some pillars to get the heights correct and mount it all. Shame all the screws in it are imperial. I've got alot of imperial taps I never use because... i've never had to. But i'll dig through and see if I have what I need.

Speaking of imperial, the worm screw cut into the shaft measured to somewhere around 4.8mm thread pitch. I cut a 5mm thread into this part to see if my lathe could handle it. Just barely... had to clean up the chatter with a file. It of course doesn't mesh well with the existing gear so i'm going to have a go at 3d printing a replacement.



Was hoping to get more done today but I spent alot of it taking the lathe apart to try find a fault that didn't exist. It needed a good clean anyways though.

Online awemawson

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Re: Sewing Machine Modifications
« Reply #27 on: April 19, 2019, 05:34:06 PM »
Your worm pitch is (obviously!) set by the pitch of the gear that it meshes with so will almost certainly not work out to round numbers - it is dependent on the gear 'family' be it Module (metric) or DP (Imperial)

Andrew Mawson
East Sussex

Offline S. Heslop

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Re: Sewing Machine Modifications
« Reply #28 on: April 20, 2019, 04:47:14 AM »
I thought I could just make the gear to match! I guess i've made another sculpture.

Seems my lathe didn't come with a 57 tooth change gear, which I've read is supposed to be standard. I've ordered that as well as a 45 tooth gear - which should let me cut a 4.75mm thread pitch and re-use this existing gear. It also turns out I can pass the 13mm bar through the headstock. I thought the hole was smaller than that. So I could cut the thread directly into the shaft like on the original machine too.