Gear teeth repair

[Dave W]

a friend brought me a job in last week. 3 consecutive teeth missing on a crown wheel.
The job was done on the basis that the thing was scrap so nothing to loose and there's half a chance it might work.

I preheated the gear and built it back up with stainless rods then ground back to shape and am pleasantly surprised with the visual results.
Time will tell if it worked.

How would anyone else have done it?

 

[MickMoor]

I'm impressed. The mesh of a crown wheel and pinion is as much an art as a science. I take my hat off to somebody who builds the teeth up from anything.

 

[REStracTORATION]

a friend brought me a job in last week. 3 consecutive teeth missing on a crown wheel.
The job was done on the basis that the thing was scrap so nothing to loose and there's half a chance it might work.

I preheated the gear and built it back up with stainless rods then ground back to shape and am pleasantly surprised with the visual results.
Time will tell if it worked.

How would anyone else have done it?

The same way as you the crap ive bodged up with the welder and grinder just to get someone going again, some worked some didnt like you say nothing to loose
Abit of satisfaction aswell

 

[fermerboy]

I've done 90 degree bevel gears on a combine grain tank and also built teeth up on a chain sprocket that was knackered by a stretched chain.
Both jobs were "emergency" jobs to get it going mid season, parts to repair were 2 days away hence I thought nothing to lose but a bit of time.
I built the teeth up using the Mig welder, didn't heat or anything, soon was a bit of heat in it with the welder anyway. Ground back to shape with the little angle grinder.
Worked surprisingly well, the chain sprocket especially. It ran the season out no problem and didn't seem to have worn much. New chain and plenty of oil though. The bevel gears were as noisy as hell but again ran till she got done. They wore till they fitted each other. Had the slides well down to not overload them through.

 

[T Bourne]

I preheated the gear and built it back up with stainless rods then ground back to shape and am pleasantly surprised with the visual results.
Time will tell if it worked.

How would anyone else have done it?

It doesn't count without pics!! Good on you for giving it a shot. I know someone who's done some pretty crazy repairs on trucks 30-40 years ago. Scary stuff

 

[multi power]

a friend brought me a job in last week. 3 consecutive teeth missing on a crown wheel.
The job was done on the basis that the thing was scrap so nothing to loose and there's half a chance it might work.

I preheated the gear and built it back up with stainless rods then ground back to shape and am pleasantly surprised with the visual results.
Time will tell if it worked.

How would anyone else have done it?

I would have done the same, except I wouldn't have heated it or used stainless rods, as I don't have any

 

[TripleSix]

Father in law built the teeth back up on a cement mixer crown wheel, with a stick welder, every single tooth.
Weld, chip off, weld, chip off....

 

[Db880]

I know it's not a gear but I've just welded a cast selector fork out of a Massey gearbox back together. I preheated first and it welded a treat. Really pleased with the results. Tractor back together and everything working. See how long she holds now!

 

[bobk]

Pictures before and after ?

 

[Dave W]

Pictures before and after ?

Er. May be issues with that.
I forgot the before and it's now back together

 

[multi power]

I've seen my dad's cousin do stuff like this all the time, a proper blacksmith, he used to fix the stuff nobody else could or would do

 

[timmyboy]

Dark skinned coloured and big white teeth, Dremel in hand !

 

[How much]

Would the stainless rods be hard enough , I didnt think that stainless was that strong ?

 

[Dave W]

Would the stainless rods be hard enough , I didnt think that stainless was that strong ?

The stainless rods stand a better chance of taking to the gear metal.
Always thought it was a fair bit harder than plain mild but could be wrong

 

[multi power]

Stainless is much harder

 

[Dry Rot]

But do you want hard weld? Stainless is also a poor conductor of heat? I am no welder but used to do a bit with hard solder and came across a company called Eutectic. (I also did business with North Sea oil companies who have experts in this sort of thing).

Eutectic produced a little booklet with very many types of electrodes, welding alloys, etc. Not sure if they are still in production but a quick Google came up with this below. If it's the same as the one I have, it is a mine of information.

https://www.amazon.co.uk/d/Books/Welding-Data-Maintenance-Repair-EUTECTIC/B0028ZLV0I

 

[Mursal]

Would stubs (cast iron) rods be an option?

 

[davedb]

Nickel chrome rods get a lot of use hear for them kind of jobs

 

[agrotron]

Welded a selector fork off a deutz dx 86 about 15yrs ago and done 6000hrs since and still going ok.

 

[renewablejohn]

Thankfully we still have a gearbox manufacturer down the road so would just get another one cut.