Main Shaft Nut

In an attempt to remove my main shaft nut I believe I have stripped the nut!
A couple of questions;
1, This is a right hand threaded nut on a one piece shaft?
2, I know the shaft is hardened, what about the nut?
3, Any suggestions on how I can get the nut off without further damaging the shaft or the internal threads surrounding the nut in the case?

Brief history:
I thought I would make another attempt at starting this long over due rebuild so the gearbox is my first victim, -literally!
I had the gearbox in the cradle chucked in a vise with the main-shaft locked down via chain on the sprocket. Good start ah!
The dummy trying to loosen the nut thought it was a left hand thread. I, I mean he was able to loosened up the nut but it wouldn't come off the shaft. The gearbox was dissembled only to find the mainshaft still attached to the inner cover. He verified it was not left hand thread, chucked the main-shaft in his soft jaw vise and watched the nut go round the shaft without backing off it. Confirmed the shaft is not broken by looking down the hollow center.

The nut on the RH end of the mainshaft is normal RH thread. You will need to cut the nut off now and hope the mainshaft survives. Jim

Carefully grind nut away if you are gentle as the metal thins close to peaks of threads you will see it turn blue. Stop and do same to opposite side and nut should spilt with few gentle hits of hammer and chisel.
I work in engineering and have used this method thousands of times I repair broke machines and make one off replacement parts so I have had lots of practise at it but be careful an take your time and the shaft is no good as it is so you can't realy make it any worse can you is the best way to think of it.

Do as Toppy says, it's the nut not the shaft threads.

main SHAFT = shaft that is splined to the clutch center; RH thread

Drive GEAR = hollow splined output "shaft" that final drive sprocket bolts to; LH thread.

Main SHAFT slips through drive gear

Thanks for the tips. I was able to drill a couple of holes through it and split it off. The threads may be salvageable but I wont know until I get a new nut. I don't have my thread gauge with me, is this a whitworth thread?
Gary

T95 said:

Thanks for the tips. I was able to drill a couple of holes through it and split it off. The threads may be salvageable but I wont know until I get a new nut. I don't have my thread gauge with me, is this a whitworth thread?
Gary

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Check for a step at the the point where the sleeve gear runs. That may give it "ssstttrrrrike 2" so to speak.