How to repair splines on pinon gear

[zimbo]

Good afternoon all,

I have a pinon gear with worn splines that needs repair. The agent wants $2500 for replacement parts as I can't purchase a pinon gear on its own, only as a kit with the crown gear too.

The pinon is off the front axle of a 60HP 4wd tractor. There is a bushing with similar splines connecting the pinon from the front axle to the drive rod from the gearbox/ transmission of the tractor.

I have taken the pinon gear to an engineering firm in the city to cut new splines.
The conclusion we came to was to deepen the existing splines after softening the shaft and machine a new bushing to fit the rejuvenated splines and drive rod splines on the other end.

Well 3 weeks later and the job not completed yet as they claim the steel doesn't want to soften through multiple heat treats and when machining they keep dulling their tool bits.

Their next idea is to turn the shaft down, buildup with welding and cut new splines to standard size and then send shaft to be heat treated by "nitrating" My question here to them is i want a guarantee that it will last and not strip under load. Are there any pitfalls with this method. They claim they have done this a gazillion times and has always worked. I am skeptical and out of my depth here. If their current tooling cant cut the splines how are they going machine the shaft down in diameter?

Any ideas on how to work this part?
What material would a pinon like this be made from normally?

I will be going there in the morning to check on them and see what machine and cutting tooling they have been using. They haven't used the shaper on it that much I know.

Appreciate your input as always.

 

[zimbo]

Sorry photo not the greatest quality.

Google Photos

 

[D Nelson]

Drill and cross pin it


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[AlfaGTA]

Grind the pinion end to a square, or hex. Make a mating coupling, snug to light press fit.
Grind the flats with a good transition radius at the end where it meets the threads. Simple surface grinder work.
Cheers Ross

 

[atex57]

I have done quite a few similar pinions. I build up with 312 stainless alloy, turn down, then cut with appropriate cutter, SLOW rpm and lots of feed.
Is this for a Massey?

Ed.

 

[crossthread]

Without knowing what the hardness of the shaft is of course I am surprised that they were not able to clean that up and make a new "bushing". It has been my experience that shafts such as that are not all that hard. As far as making that repair I can only offer what I did once. I had to fix a splined shaft similar to yours which was on an antique tractor and parts were no longer available. I welded up the shaft and cut new splines. I did not harden the shaft and it is still running fine.

 

[Turbowerks]

Without the blueprint from the manufacturer its a guess on material.
More than likely its a 8620 or 9310 type material. Case hardened. But could be a through hardening but I don’t think so. I build gears from 8620 and shafting from 4340 or 300m (read expensive).
I have redone splines on occasion but you really need to pay attention to materials and process. Usually i use a crankshaft radius repair wire on submerged arc with proper pre heat and post temper its about 38 rc when finished. cut in that state on a gear hob.
Slow feeds and speed,hard on hs hobs.
But anytime you weld a shaft like that for buildup, no guarantee its not going to break at some time


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[Mud]

Stoffel Polygon Systems does repairs like that, if shipping the parts is possible.

https://stoffelpolygonsystems.com/wp-content/uploads/2017/12/Stoffel-White-Paper.pdf

 

[gbent]

Cheap solutions, in keeping with the location, as has been stated, cross drill and pin it. Weld it. Build up individual splines with a mystery metal rod such as Supermissile weld or 312 stainless and machine to suit. A snug fit will be aided by a liberal dose of Locktite.

Better pictures may get you better solutions. Include the mating part.

 

[dsergison]

I once repaired a very loose spline on my flywheel/crankshaft.

I flattened tig wire filler into strips and drove it into the spaces, with locktite.
You have to drive the wires into the teeth in an opposing pattern like tightening wheel studs to keep it centered.

It has worked for 15 years. Link to pics.

Spline question

 

[jspivey]

This "engineering firm" sounds incompetent if they are not even able to anneal the material, regardless of what the steel is. Also, I would think that nitriding is not necessary for this application. Seems like another way for them to get your money. I would look for a second opinion.

 

[tim9lives]

Why not just braze it with O/A and bronze... machine to proper diameter on lathe then recut splines. Cutting the splines at same position as original eliminates any dulling of cutters since you are only cutting into bronze. Not all that complicated in my opinion. KISS

FWIW... goes without saying but I’ll say it anyway. If I was doing it I’d first thoroughly degrease it, then do a decent heating to make sure there’s no remnants of oil on it and then wire wheel with a clean wire wheel to clean splines to bright clean metal. Lots of flux and then braze. Also, measure and write down specs of splines before you build it up with bronze. Leave a small spot of the spline untouched, just so you have a starting point for when you recut the splines.

Cheap and dirty....Clean both sides....JB Weld and drill/pin it. But God help the next guy who tries to disassemble it... if it’s even around when it comes to needing that

 

[D Nelson]

How about a key way I’ve seen a 1/4 key take some pretty big horse power and easy to install
Don


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[Phil in Montana]

There has been some really bad advice given on your spline repair, If a full set of splines could not hold up and last why would a half as.. repair work? I fixed this type of wreck weekly. I don't know why the local shop could not anneal the pinion, maybe not the right heat. The most common steel would be 8620 carbonized but it don't have to be could be other alloys. To repair the spline you would anneal the splines, try to work out what the spline is, (looks like 60d with a flat bottom, but it doesn't have to be could be something other) Machine the splines away with a .030 undercut, preheat spline area only 500f and weld up with sb 28 .045 wire with argon/ 02 gas, at no time let the shaft get over 850f, might take a while to weld up to keep the shaft cool. You don't want the gear to heat up or you will pull the heat treat out . I cool the gear with air and mask it so no spits get on the surface and use glass tape to protect the threads and bearing fits. After the welding I post heat the weld only to 700f and cool with air. It is straight forward to machine and cut new splines. Use a new yoke as a go/ no go gauge. I never had one brake but with unknown steel it sure can....Phil

 

[zimbo]

Hi Ed,
No A SAME Solar 60.
And the splines with the 312 SS will hold up well once 4WD is engaged and handle the torque?

Greg.

 

[atex57]

If you do not overheat it while welding it should be fine. I asked if it was a Massey as I have done a few pinion shafts for them. Mostly for tractors I do input shafts for the transmission

Ed.