Was removing, now installing PTO shaft ??s

lhfarm · Jun 5, 2005

Got the shaft off a very old (at least 35 years) 5' Bush Hog brand mower. The tractor end of the shaft was set up for a 1 1/8" spline and I need a 1 3/8 quick coupler. The mower end was keyed and had a bolt through the shaft too. Purchased a King Kutter replacement shaft - I matched the length and shaft sizes at TSC. The fit is perfect, except the shear bolt size. The new shaft has a 1/2" hole and the mower is 5/16".

Should I drill out the mower shaft (not going to be easy) or try to find a matching end (small shear bolt hole)?

Should I add a slip clutch (torque limiter?) between the mower shaft and the drive line?

Any suggestions appreciated.

Slamfire · Jun 5, 2005

Oh, wow! A 1 3/8 to 1 1/8 adaptor would have set you back less than $10. /forums/images/graemlins/shocked.gif

lhfarm · Jun 5, 2005

( Oh, wow! A 1 3/8 to 1 1/8 adaptor would have set you back less than $10. /forums/images/graemlins/shocked.gif )
Before I got the new tractor, that was what I was using. It had a pin hole for locking onto the PTO shaft. My new tractor doesn't have the hole. So I tried to find a quick connect 1 3/8 to 1 1/8 adaptor, but no luck. So I had one welded up. Last weekend, a buddy was helping me mow and engaged the PTO with the engine at 540 RPM and snapped the 1 1/8 spline where it went into the old driveline. Scared the &&&^^ out of me. For safety, I thought I should get the correct style shaft.

ThistleKop · Jun 5, 2005

Should I drill out the mower shaft (not going to be easy) or try to find a matching end (small shear bolt hole)?


Barry,
Do you have sufficient length to cut the end off and drill the hole size you want in the shaft? I wouldn't concern myself with a slip clutch with a 5/16" shear bolt. It should shear before damaging something else.

TK

ChuckT · Jun 5, 2005

I run our brush deck with an Over-Running Clutch. This is in addition to the shear bolt at the implement end of the PTO shaft. The clutch lets the deck free-wheel when the tractor stops - preventing the momentum of the blades transfering back into the tractor and continuing to push it forward.

cvt

lhfarm · Jun 6, 2005

I am using bronze bearings to reduce the 1/2" to 5/16" and that seems to be working ok. I figure the smaller size is just another safety factor.
Thanks for all the replies.

Soundguy · Jun 6, 2005

I would either bushing down the 1/2 holes in the yoke to 5/16 and use the 5/16 bolt, or I would take the pto yoke, turn it 90 degrees and drill a 5/16 hole thru it.. make sure it is square.. use a drill press or let the machine shop do it.. might set you back 10$ if you walk in at lunch time, cause it will take the guy less time to chuck up a mill than to make out the 'paperwork'.. etc.

soundguy