We have a problem with the ring gear on our Model K. Two teeth are damaged. Has anyone had any luck building up teeth on a ring gear? What's the best process? We don't have time to make a new one, and I'm determined to try welding.
I have seen it done many times. On the tractor forum, they replace one or two teeth all the time on the rare ones.
Rob, how bad is the damage? Can you show us?
Is warping a concern? Hardening? Maybe try building with hardened nickel rod? Thanks for any info (and the positive news). This is a problem that came out of left field and set us back quite a lot. We thought we had a replacement carrier and ring gear (thank you Bob T.). However, it turns out the replacement ring gear and carrier were ever so little different (pitch and location of the gear in relation to the pinion) that all of a sudden, we are making a new carrier and repairing the original ring gear.
I have know of teeth being welded on cluster gears, and they held.
I remember teeth being brazed too, but I would not think they would be very strong.
I would take it to a certified welder, have him build up the teeth, or tooth, and take it home and grind the tooth/teeth to shape.
You may have to go back and have more welding done, but it can be done.
If the teeth are straight, like on the T ring gear, it should not be too difficult to repair.
Keep in mind that breaking a new tooth could get between the ring and pinion and break the differential housing open.
I would think a good welder would know how to do it in order to correct the hardness of the teeth and avoid warpage, I am not a welder of that caliber unfortunately. I suppose TIG would localize the heat in order to avoid warpage, but I will let others chime in.
Thanks guys. This is a poor pic of one of the teeth. Another is cracked:
Contact Craig Anderson in Wisconsin. He had a tractor restoration business for many years. He's a member here and posts occasionally so should be easy to hook up with. He will know who can do it and do it right the first time.
That ring gear will have to be bolted to the Carrier when welding to keep it from shrinking. Tig will be the best process to use. Contact one of the manufacturers to find anyone doing this type of service. The filler metal will be from one of the industrial filler metal companies in the USA or UK. Maintenance welders are your best bet.
No I cannot do this w/o practice on a similar piece and research. Can it be done successfully yes! Donnie Brown would be a good contact here too.
Is that a steel or cast iron gear?
I presume it's a Dodge Brothers product so must be steel.
Either way it can be fixed though steel is easier.
Thanks for the call out Stan.......
Thanks guys. Craig, yes, Dodge and steel. I can ship tomorrow.....
I would suggest that you take it over to Silverstrand just west of Raymond. He deals with all kind of equipment repairs like this and I am sure he could weld it up and machine it for you. Not only would you get quality work, but it is local.
Welding on ring gears was common back in the day too, here is some info. But equipment has changed, and a good shop would mill the teeth back, this craftsman used a hacksaw and file!
"... and I'm determined to try welding."
What happens if you "try" it and it doesn't work? Bad news. As long as a better solution exists, I would never try this. Just my 2 cents.
I don't know about the K gears but the original T ring gears are not very hard at all. You can file teeth on them easily. I ran a speedster for a lot of miles on a ring gear that I smoothed up the teeth on a belt sander. I didn't have money for a new set in those days.
Later T ring gears are hardened.
People who know how to do this do this. There are thousands of old trucks and tractors with steel ring gears running around that have had teeth built up with welding. I do think I'd mix up some casting cement and make a pattern off this one first so I had a pattern but I don't see a lot of alternative to welding it. What would you have done if you were in Milford, Nebraska and broke a tooth off the ring gear in 1908?? You'd have taken it to the local blacksmith and he would have welded in a new tooth and got you back on the road.
Thanks guys. Dan, good article. Jerry, my plan is to run with a welded gear if it appears safe while a new ring and pinion are being made. A person only gets so many summers driving these cars and I've already missed half of this one. I hope not to miss the entire season. When I'm gone some (many) will say I wasn't the smartest guy, but I 'll be damned if anyone will say I didn't get my cars out and drive them......
A few more pics:
Well. I would say the obvious thing is to get one of the really good gear makers used to making these for horseless carriages to get busy so you will be set for next year.
For this year. I almost posted earlier on this thread, but thought my minor experience here would have mostly been thread clutter.
Many years ago, when I was working on my first model T, I wound up with a mismatch of gears that I did not want to ruin the good gear I had against the other gear that I had that was damaged. I tried for several days to find either a better but not perfect pinion gear to run against my marginal ring gear, or a really good ring gear to use with my nearly perfect pinion gear. Finding neither, and wanting to drive the car and not ruin the perfect pinion I had, I asked some welders I knew, whose opinions I valued.
Then I did it myself. I brazed in three damaged teeth on a bad pinion gear using nickel-bronze. The thing with nickel bronze, is that it is somewhat self-hardening. What you put on in the first layer, melts at a higher temperature than what you are putting on fresh with the new rod. This means you can do what they call "flame shaping" and build the tooth up close to shape. This leaves less hand filing to be done. The self hardening nickel bronze also wears (not great) fairly well. Such a repair (call it what it is, a patch) can never be as good as a properly made steel gear.
I built up one whole side of three teeth in a row, then hand filed them to final shape. I drove that car for about a year until I got around to finally changing the gears out, and had put well over a thousand miles on it. I still have that pinion in my stuff as a possible emergency replacement.
Three teeth in a row is far worse than an individual tooth because at one point, all the stress is on brazed teeth. An individual tooth will always share the load partially with at least one other tooth. The pinion gear is worse because it goes around three times for every once the ring gear does.
For two individually broken teeth on the ring gear, you could probably get a couple good years out of a nickel-bronze repair. You would need to use a die grinder (or something similar) to cut the damaged area back enough to try to eliminate any metallic cracks at the breaks. If you can salvage half the original tooth, aided by the nickel-bronze, it should be good for a couple thousand miles.
Just relating my experience.
Drive carefully, and enjoy, W2
Thank you for sharing your first hand experience.
As it turns out, Ford made a standard, 3:1 gear set for the Model K, and offered an option of 3.75:1. The 3.75 ratio diff included a different pitch ring gear (although the same number of teeth), different carrier, and 12 tooth pinion instead of 15 tooth. We ended up with what must be an ultra rare 3.75 ratio carrier and ring gear. Now we must make a new carrier based on the original (to the car) 3:1 carrier, and re-use the ring gear with two damaged teeth.
If it was easy, everyone would be doing it......
Hi: What your looking for is a Micro welder. Find a plastic mold shop and they will know of one in your area.
I've worked with this shop "they are the best in the business"