# Advice on gear making!



## pjf134 (Dec 21, 2011)

Has anyone made a gear that the teeth face inward instead of outward? I do have to make one before spring, and yes it is for a front wheel drive mower. The mower is in good shape and the gear is messed up on one of the wheels. The gear is costly because it comes with the wheel, but if I can make the gear and machine out the old one and screw in the new part it would be great and justify the lathe and mill with the wife.
 Paul


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## Tony Wells (Dec 21, 2011)

I've done them on a shaper, but never any other way. Small ones are sometimes broached. What is the tooth profile?


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## pjf134 (Dec 21, 2011)

Tony,
  I will take a pic of it on wed., but if I remember right the I.D. is about 3" and plastic. It's been on the honey do list since the summer, but I do have extra mowers and a tractor so it got to the bottom of the list then. It's been awhile since I looked at it but I do think it has a profile like a normal outside gear, but I will have to check on that.
 Paul


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## Tony Wells (Dec 21, 2011)

Well, in plastic, it would not be out of the question to drag the teeth with your lathe, provided you had a proper way to index the blank to get the pitch you need. You'd have to grind a HSS bit, but that's not too difficult.


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## Pacer (Dec 21, 2011)

I've never done one, but was thinking about your question ...

Since it doesnt need high precision, how about set it up on the rotary table or indexer and find a close enough sized drill bit (or end mill) for the root (like chain drilling, which looks like gear teeth) and then rough mill/file the rest of the tooth profile. 

I've seen where 5-6 broken teeth on a gear was done similar to this by welding/brazing over the damaged teeth and then cleaning out between them by drilling/filing.

Let us know what you come up with...


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## pjf134 (Dec 21, 2011)

Here are the pics of the gear on the good side. The I.D. of the gear is about 5 1/4".
Paul


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## AR1911 (Dec 22, 2011)

Brass or aluminum. Looks like the teeth are rounded?
that plastic drive gear may wear more quickly on a metal gear unless you polish it.

You could turn the ring on the lathe, cut a form tool, index the lathe spindle on the backside with a gear that has the same number of teeth, then push the form tool across the ring with the saddle.


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## Tony Wells (Dec 22, 2011)

Built like  forklift drive. The drive gear would likely be metal, but it would be safe to build the driven gear out of aluminum or brass.


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