Repair existing flywheel ring gear

[cayankee]

Hi Guys,

Although I've only done it for myself, I have had great success with using my MIG welder loaded with stainless #308 wire to buildup worn, missing and broken gear teeth when replacement gears are hard or impossible to find.

I generally make a jig or guide for the nozzle to follow to get accurate placement of the weld filets. Then I "rough out" the general dimensions with a Dremel tool and hand finish with hand files using a following gauge patterned from a section of teeth with the least wear so I can match the pitch and other dimensions of the teeth as I hand work them.

It's tedious and takes some time to do, but the results have always been a vast improvement than what I started with and only cost me my time. The results will only be as good as the time you put into it.

[Neil]

Sounds like a solution. Are the "new" teeth robust? What's the worst chipped off tooth you fixed e.g. broken right down to the ring? Any pics by chance?
I know Ray will be interested in your findings. Seems like it could be an inexpensive fix (if you don't include labor)
Cheers,
Neil.

[puffer@rpi.edu]

CAYANKEE,

Also, do you need to do any heat treatment after you finish? I have a messed up generator drive gear that I might try fixing first. If I screw it up I know I can get a replacement. Ray

[cayankee]

Sounds like a solution. Are the "new" teeth robust? What's the worst chipped off tooth you fixed e.g. broken right down to the ring? Any pics by chance?
I know Ray will be interested in your findings. Seems like it could be an inexpensive fix (if you don't include labor)
Cheers,
Neil.

Hi Neil
One job I did, I "repaired" (replaced actually) two teeth that were missing off of a "Bull gear" on a machinists lathe I acquired. Been using it for years. It's only a 1940's South Bend 9" Model "A", so the loads I've put on the gear have been moderate. They haven't come off yet, but do show a little wear... no appreciable distortion though.

If I was to do it over again, I think I would try to experiment with the application of "hard facing" alloy to increase the repaired teeth's resistance to wear, but I really wasn't sure I could get the finite control needed for application using a stick welder as that is the only format of hard facing material I have. If I had a TIG welder I would have tried that if I could get the proper alloy. Can't really touch it with a file though.. too hard. Would have to finish really carefully with the Dremel or a thin diamond file maybe.

If I had a kiln, I might try a case hardening treatment or maybe an oil quench to temper it. It's a cast gear and I didn't want to alter the metal's grain structure throughout the whole gear not knowing how it would affect the rest of the gear, so I only took the repair to the level I needed to get the job done.

[cayankee]

CAYANKEE,

Also, do you need to do any heat treatment after you finish? I have a messed up generator drive gear that I might try fixing first. If I screw it up I know I can get a replacement. Ray

\

Hi Ray,
One job I did, I "repaired" (replaced actually) two teeth that were missing off of a "Bull gear" on a machinists lathe I acquired. Been using it for years. It's only a 1940's South Bend 9" Model "A", so the loads I've put on the gear have been moderate. They haven't come off yet, but do show a little wear... no appreciable distortion though.

If I was to do it over again, I think I would try to experiment with the application of "hard facing" alloy to increase the repaired teeth's resistance to wear, but I really wasn't sure I could get the finite control needed for application using a stick welder as that is the only format of hard facing material I have. If I had a TIG welder I would have tried that if I could get the proper alloy. Can't really touch it with a file though.. too hard. Would have to finish really carefully with the Dremel or a thin diamond file maybe.

If I had a kiln, I might try a case hardening treatment or maybe an oil quench to temper it. It's a cast gear and I didn't want to alter the metal's grain structure throughout the whole gear not knowing how it would affect the rest of the gear, so I only took the repair to the level I needed to get the job done.

[drujinin]

They referr to welding missing teeth on machinery, then finsh with a grinder and a file. There is no referance to heat treatment.
I know a couple of guys who have welded teeth back on crawler final drive bull gears and not had a problem. They don't figure on wear due to the fact that these are occasional use tractors. "Show Toys"

[64farmboy]

They referr to welding missing teeth on machinery, then finsh with a grinder and a file. There is no referance to heat treatment.
I know a couple of guys who have welded teeth back on crawler final drive bull gears and not had a problem. They don't figure on wear due to the fact that these are occasional use tractors. "Show Toys"

I TIG welded up the splines on a spider gear shaft for a Belarus 4 wd tractor, rough ground it with a 4 1/2 grinder then finish ground it with a dremel tool so the gears had a good slip fit. It had about 3 inches of spline gone in the middle of the shaft. I had it heat treated (case hardened) its been in the tractor for 3 years and the old farmer that owns it really uses it.
Just my experience

[Old 3T lover]

They referr to welding missing teeth on machinery, then finsh with a grinder and a file. There is no referance to heat treatment.
I know a couple of guys who have welded teeth back on crawler final drive bull gears and not had a problem. They don't figure on wear due to the fact that these are occasional use tractors. "Show Toys"

I did a "Patch" job on a 3T D-7 for a fellow once. Used a well worn pinion gear, welded two teeth on the reduction gear and two teeth on the bull gear among other patches in the same final drive....I was fussing the whole time about, "This won't work". Well, he ran it every day for 2 years, junked the tractor and put THAT final drive on another tractor and ran it a year or more before selling it.

I guess you never know what will work until you try it.

[Neil]

Well that sounds promising because it appears I've lost all the teeth off my final drive pinion it seems. I can turn the (stuck) left steering clutch but the sprocket does not turn. If that turns out to be the case, I'm probably better off getting a used pinion.
Cheers,
Neil.

[puffer@rpi.edu]

Well that sounds promising because it appears I've lost all the teeth off my final drive pinion it seems. I can turn the (stuck) left steering clutch but the sprocket does not turn. If that turns out to be the case, I'm probably better off getting a used pinion.
Cheers,
Neil.

Neil, I think I got my pinion from Dennis at Omnitrac. Ray