Fix gears?

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I have welded up more than a few gears in the past to "get by" or because the application wasn't worth the price of the gear. Honestly I have had about a 50% failure rate with "fixed" gears but I must add that every gear was missing at least one full tooth.Now on a project I am working on I came across a nearly irreplaceable (expensive) gear that has problems. No missing teeth yet but if it is a good idea? I would like to fix the few very bad teeth pictured below before they completely shear off. The gear is hardened like most normal gears. After cleaning of coarse would a quick hit with the tig and filler in the craters and then reshaping work out? If it is fixable can I please trouble the gurus for some welding tips? Craters are from the lower few teeth sitting in water for 20 years causing rust.
Reply:I would think your wasting your time since that gear is case hardened and the welded area wont hold up long at all.....also the part of the tooth you want to repair is probably the weakest part of the tooth......If it was that easy everyone would be welding gears.....Now if your going to heat treat it after you weld it up......That might work.....The filler rod will be a factor on the end result so don't just use any filler rod laying around.......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:Done similar repairs before with nickel bronze rod with very good success.Ive even built up a starter motor gears a few times with good results.Bottom of page..........http://victortechnologies.asia/IM-Up...onze%20Rod.pdfLast edited by LarryO; 10-10-2012 at 11:56 PM.
Reply:Thanks for the responses! Thanks for the filler tip, I will check the lwss and see is he has them in stock just to know.
Reply:VPT, look up Eutectic.  They have many specialty rods and may help.  give them a call.  Best  Bob
Reply:A friend of mine repaired a vintage ring gear using Crowns Royal 220-M.Granted this is a collector car that won't be driven every day but it worked for the intended purpose.
Reply:I wonder if you could weld it up, then machine the teeth to shape, then case-harden it...? I think Brownell's sells case hardening materials.
Reply:You could check with Boston Gear, and perhaps obtain two matching gears which you might bore for a "center section" to duplicate your part.http://www.bostongear.com/products/open/index.htmlWhat does your gear fit? Also, check the Practical Machinist forums as they are a great resource.
Reply:Won't match original hardness after welding, but successful gear-tooth repairs are done every day. I'd use 312 for the filler, and of course keep heat to a minimum.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:There is a place we use in Providence R.I. that will cut any gear if you provide the blank and tell them how many teeth..http://www.traceygear.com/english/Pr...FSXNOgodfAsAEAThey take it from there so never say never....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I know a gear can be made, but I am sure it will have nasa price. Thanks for all the info and input everyone so far! I will look into the case hardening deal. Have other stuff to work on today, this project may take awhile so I am in no rush for it.The gear BTW is for a 60's coot. Yes I know with a search 6x6 has some gears listed for the coot but not the double gear. Farmall has a good point about putting gears together though. That might be another option.
Reply:Way way back my brother in law had a coot. Besides go anywhere, eat gears is what they did. I had to chain up all four and my jeep and go way back in one time and drag him out to hard ground. That all posi traction was tuff on gears. Been a long time but seems like he said that brass/bronze gears was the answer. They would wear but didn't disintegrate. Can't recall for sure. Been too long now."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Originally Posted by SandyWay way back my brother in law had a coot. Besides go anywhere, eat gears is what they did. I had to chain up all four and my jeep and go way back in one time and drag him out to hard ground. That all posi traction was tuff on gears. Been a long time but seems like he said that brass/bronze gears was the answer. They would wear but didn't disintegrate. Can't recall for sure. Been too long now.