DIY sprockets

Anyone here ever make their own sprocket? I’m in a situation where the teeth are bad, the sprocket is very specific, and I’m unable to find a new one. Since I refuse to replace it with a used one I’ll have to build my own. I plan on cutting the hub out of the worn sprocket and welding a new sprocket with the center cut out in its place.

This is the hub of the sprocket in question. The teeth have already been removed. A Jawa crank clutch side fits the taper so I’m able to turn it true.

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Re: DIY sprockets

Tractor supply has sprockets with no center hub, I'm sure others sell them.

Re: DIY sprockets

Ben Whittle /

I’ve checked tractor supply and online without any luck

Re: DIY sprockets

Alberto Einsteiner /

Try a real bearing shop replacing only deals with bearings pulleys belts sprockets and little gearboxes.

If they don't have it in stock they should have a catalogue in the store that will line you up with something you can make work. (edited)

Re: DIY sprockets

there are a number of sprocket shops that will custom make sprockets. I had to do this to get dirtbike wheels on stuff before cuz they didnt make sprockets in the 420 or 415 chain sizes. Runs about 40 bucks depending on size, which is on par with alotta stock sprox.

Making your own is iffy, but if you've got a lathe or something it's very doable. the trick is getting it centered. even a little tiny bit off center means your chain tension is inconsistent and you can feel it like a surge kinda jiggle when riding.

Re: DIY sprockets

Have you looked at http://www.mcmaster.com/# ?

Re: DIY sprockets

Gears Made

Found this a while back, and may have some work for the guy in the coming weeks, but have no personnel experience yet. I've tried doing gears on a lathe before; it's possible for sure, but (imo, & on the first try) a magnitude more difficult than YouTube makes it seem (that said, this is a sprocket, which appears to be different from cutting worm gears; I'd still imagine it would require the creation of new jigs, toolings, measurement tools, etc.).

Or maybe a steady hand, some good bits, and a Dremmel? Keep up posted. (edited)

Re: DIY sprockets

Ben Whittle /

I’ll be asking the guy in the machine shop where I work if he’ll do me a favor. That way it’ll be true. Only issue I can think of will be cutting the center out of the new sprocket. I was planning on using a 1.5” hole saw and a spacer that has a 1/4” I’d and 14mm I’d to keep the pilot bit centered in the puch 14t sprocket.

Re: DIY sprockets

Totally normal JBOT /

Use a lathe and make the fit Niven tight.

Then press the new outer teeth onto the hub, then weld.

Nbd

Re: DIY sprockets

Ben Whittle /

Scratch the hole saw and centering bushing plan. Left work a few minutes early today to catch the guy in the machine shop we have on our facilitys. He said he’d do it no problem. Although the lathe chuck has three jaws and the sprocket is a 14t, he got it centered up and cut fairly easily. Then he turned down the old sprocket hub to .005” larger then the new sprocket. Super cool dude too! Met him that day too. Debured everything with a sanding wheel in the dremel and whiped down the hub with some WD40 to prevent flash rusting. Now I’m freezing the hub and baking the teeth at 450* in the oven. Hoping things slide together easily.

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Re: DIY sprockets

Charles Cole (OFMC) /

When I did aerospace contracting, it was a common practice to dip/shrink the parts in liquid nitrogen, cause most fasteners are 'interference' fit. They also had fasteners that most people have never seen or not available in hardware stores. This method would surely work for you along with some spot tig welds.

Re: DIY sprockets

Ben Whittle /

Pressed on the teeth and check trueness in the drill press. Pretty spot on. Four tacks on the inside to keep it from moving when the weld are added. Checked again in the drill press and nothing moved. Glass bead blasted to clean it and gave it four small beads of weld. Checked it in the drill press again and still true. Half ass high temp black paint job to cover the welds. Test fitted a section of chain and nothing touches. Bam, DIY sprocket. Very pleased with the results. (edited)

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Re: DIY sprockets

Ben Whittle /

Also after it was welded and cooled I heated it with an O/A torch till it the steel changed color slightly. Then quenched it in lightweight oil.

Re: DIY sprockets

Alberto Einsteiner /

That looks pretty damn good Ben I don't think you will have any problems at all.

Re: DIY sprockets

Rebuilt the ring gear on a Vauxhall Chevette (Opel Kadet to you guys??) with a mig welder and angle grinder once.......... did me proud for many 1000s of miles!!

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