Posted by Michael Hernke [75.205.167.0] on Wednesday, December 23, 2009 at 10:32:05 :
In Reply to: Re: how to weld posted by David Sherman [24.32.202.83] on Wednesday, December 23, 2009 at 03:33:31 :
I believe when I measured the PTO speed it was ~1/3 engine speed on my M37 so if you don't rev the engine too much when winching I agree that balance shouldn't be an issue. Even if your shear pin fails I would be surprised if you can break a pto driveshaft figure even if you have peak torque at idle you have less than 200 ft/lbs times 3 which is only 600 ft-lbs on the shaft. I would have to get out some old engineering books to figure the metal stress due to torque but I know I have used a 6 ft cheater bar on a 1/2 breaker bar with a ~1/2" diameter extension. 200lbs X 6ft = 1200 ft-lbs and I know the pto shaft is at least twice the diameter of my extension and further the strength of a shaft goes up with the square of the diameter so twice the diameter = four times the strentgh. I think the pto shaft is sized to prevent whipping or buckling not torque so you should be fine.
Another exaple of how over sized the pto shaft is my on my admittatly most likely weaker M37 pto my yoke seized on the winch shaft rendering the shear pin useless and I drove the pinion gear in the winch trough the front bearing cap before without any damage to the drive shaft.
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