Rotary Cutter Keys and Keyways Mower Blade Bolts

[LConrad]

Have a Howse 5' rotary cutter and the keys have worn off the blade bolts and the keyway is pretty well worn oblong on one side of the stump-jumper. I thought about building up a key on the bolt with some weld and careful grinding but with a worn keyway I'm not sure that's even worth it. That left me thinking of grinding some flats on the bolt head so it was easier to get the pipe wrench on it next time or just welding some nuts on and grinding them off each time if these aren't heat treated, don't want to do anything that would help a blade fly off.

What have you settled on?

 

[LD1]

Buy new bolts.

 

[geneP]

Being the do-it-yourselfer that I am, I would have to give the welder a try. If the keyway is worn you can build a higher/wider key to stop the slippage. I've done it before. Grind it close with the 4" angle grinder and fine tune with the dremmel if necessary. It takes time, but I'm retired and I have time to tinker.

 

[LConrad]

Being the do-it-yourselfer that I am, I would have to give the welder a try. If the keyway is worn you can build a higher/wider key to stop the slippage. I've done it before. Grind it close with the 4" angle grinder and fine tune with the dremmel if necessary. It takes time, but I'm retired and I have time to tinker.

That is what I would have liked to have tried. I appreciate the encouragement. For better or worse the powers-that-be went with new bolts and J-B weld on the keyway. Is what it is I guess.

 

[Soundguy]

jb weld? run away fast!


new bolts for sure.

I never re use mower blade bolts. asking for trouble. same with jb weld.

 

[SPYDERLK]

Have a Howse 5' rotary cutter and the keys have worn off the blade bolts and the keyway is pretty well worn oblong on one side of the stump-jumper. I thought about building up a key on the bolt with some weld and careful grinding but with a worn keyway I'm not sure that's even worth it. That left me thinking of grinding some flats on the bolt head so it was easier to get the pipe wrench on it next time or just welding some nuts on and grinding them off each time if these aren't heat treated, don't want to do anything that would help a blade fly off.

What have you settled on?

A worn keyway means the bolt has been moving in use. The shoulder socket on the blade carrier is now compromised. ... The torque spec on those bolts is ridiculously low. This the result of following it with old bolts with rust in the threads. ... I tighten my bolts, cleaned and wetted with WD40, to stall using an IR TI Max on a short hose at 150psi supply pressure. I have seen them loosen with lesser impact guns.

The widened keyway is not important. Just tighten the new bolts to 30 to 100% above spec.
larry

 

[LD1]

All the key does is allow you to tighten the nut. Even a worn soppy key will achieve this. But you need new bolts. They are critical, and inexpensive. Don't weld on them.

I have had to weld hex bolts on The round head before to get them off. But they get discarded and replaced

 

[LConrad]

I hear you loud and clear on JB weld and new bolts. We've got the new bolts at least. I threw my two cents in based off all your advice and I appreciate knowing how to treat this right if it were totally in my hands.