1280 final drive progress question?

daveminn · Mar 31, 2016

working on my 1280 case excavator to get the new final drive shaft back in and new pillow block bearings on.question,book shows 23 teeth on the drive sprocket and mine has 21.always noticed it would creep on one side when running it before it broke but not real bad,if the other side has the original sprocket of 23 teeth on it(real hard to count as it is covered with guards and shields)Is it going to be hard on the separate drive motors if I put the old one back?There is not another one available in the whole world as I have exhausted 3 days of looking for one!!Also going to broach in a 1/2 inch keeyway since the center of the splines is ground up,will one keyway work if we build up the wore area and machine it down?will welding up the shaft and milling it back cause the weaking of the shaft?Thankyou guys,your the best!!Dave A

NCWayne · Apr 2, 2016

Being hydraulic the drive motors aren't really going to know the difference. In fact the ground speed is going to be controlled by your steering controls. As a result, you can feather the controls so both sides operate at the same speed and the machine tracks straight. The only issue you'd have would be pushing both controls wide open, causing the motors to run at the same speed....but with the one with the most teeth moving it's track just a bit faster than the one with the lesser amount of teeth.

As far as building up, and machining the shaft, go for it. Dad and I built up, and machined, many shafts over the years, and never had any issues. In fact we did the same thing your talking about doing on several occasions when a splined shaft was screwed uo, and used keys -vs- the splines.

Good luck. Hope things work out.

daveminn · Apr 2, 2016

NC Wayne question?Will 1 key way work or would we be better off going with 2??Thankyou for all the advice you have helped me with!!I really appreciate it.Dave A

NCWayne · Apr 3, 2016

Not a problem with the help. As far as the keys, obviously going with two would be better than one. If nothing else it helps take the 'rock' out of a single key setup. As for the size of the key, what is the shaft diameter? I ask because I didn't catch it before, but a 1/2 key, even two of them, sounds awful small to me. If you think about it, in the beginning each spline was a key in and of itself. If it has torn/worn those to the degree it has, your going to need larger, or more, keys.

Too, if your going to build it up and machine the shaft before doing the key ways, machine it a bit undersized before you start welding. I say this because you don't want to be machining the shaft back to size and have the finished surface right at the root of the weld. By machining the shaft say .020 or so smaller than the finished size, that won't be an issue.

If you've got any more problems give me a shout. I'll be happy to answer anything I can.

1280 final drive progress question?

daveminn

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NCWayne

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daveminn

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NCWayne

Well-known Member

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