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Thread: Motorizing a Leather Patcher manual sewing machine (WIP)

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    polyfractal's Tools

    Motorizing a Leather Patcher manual sewing machine

    Still a WIP, but someone swung by my channel and mentioned folks over here might be interested

    I picked up a cheap leather patcher machine (also known as a cobbler's machine), which is a cheap knockoff of Singer's 29K machines. They are designed for patching shoes, bags, patches, etc and are most often used on the street for quick repairs. The machines are super crude castings and roughly machined parts, but get the job done. Big hand crank, beefy needles, long arm to fit deep into bags/boots/etc.

    I'm adding a motor to mine, and then will clean up the casting/machined parts to make it a little more polished. I'm using a brushless "hoverboard" hub motor and coupling it to the patcher via a v-belt. Fabricated a v-belt pulley for the machine out of tooling plate aluminum, and a small adapter to mount a cast pulley to the motor. The motor was chosen because it's a low KV motor (~600 RPM max) and very torque'y for it's price (10-12NM based on other hobbyist's tests). They run $30 new on ebay, $15 used. Hard to beat that price

    The remaining work is to mount the motor and build a replacement stand (since the tripod that comes with the patcher is useless). I don't currently own a lathe, so there were some...uhh... creative arrangements to fabricate a v-belt pulley on a milling machine


    (Apologies for audio on this first video, things went a bit wonky in post-production and I didn't notice in time)


    Last edited by polyfractal; 02-14-2019 at 04:02 PM.

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    giangthetool (02-08-2019), Jon (02-08-2019), PJs (02-09-2019), rlm98253 (02-08-2019)

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    Last video in the series (at least for now) is up!



    It's a short one, basically just machining a small bracket to hold the d-shaft of the motor. Then just a matter of screwing everything down onto a temporary 2x4 and wiring up an ESC + PWM generator to test it out.

    The runout on the motor pulley is embarassingly bad, but since it's low RPM and low force I don't think it'll really matter I'll eventually build a proper stand for this, or maybe just bolt it right to my craft desk

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    Jon (02-14-2019), rlm98253 (02-15-2019)

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    Love the video but you gotta tell me the name of the song and the band playing in the video !!! I NEED THAT BLASTING IN MY SHOP !!!

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    Haha, thanks

    The first song is "Say You Will" by "Wellmess", but I think they only do "licensed" songs for YT, TV, etc. Or at least, I can't find any more details about the band anywhere

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    Thanks polyfractal! We've added your Leather Patcher Modification to our Leathercraft category,
    as well as to your builder page: polyfractal's Homemade Tools. Your receipt:




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    Quote Originally Posted by DIYer View Post
    Thanks polyfractal! We've added your Leather Patcher Modification to our Leathercraft category,
    as well as to your builder page: polyfractal's Homemade Tools.
    Ah cool, thanks!

    Just a quick, final followup: a bunch of people requested some footage of the machine sewing. So here's a quick video showing it sewing different thicknesses of leather:



    The leather being tested is maybe ~4oz oil-tanned pullup. It's not supple, but not super stiff either. The four-layer test was about 7.5mm thick. I should have grabbed some stiff tooling leather but didn't think about it in time.

    For whatever reason, I was under the assumption that DP-35 / 134x35 needles would work in the patcher... thought I had read that somewhere. Well, they are too long and it messes up the timing. Luckily you can just cut/grind them to size and everything works as expected, even though they don't have a flat. I found a lot more chisel point options in DP-35 than Hax1, as well as larger sizes. In the video I'm using size 69 polyester thread, but have used 92 as well.

    Think that should wrap up this patcher project. I need to build a stand/tripod, and properly mount the motor, electronics, etc. But overall it's pretty much done


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