Rotary Cutter Brush Hog Blades COMING OFF

[Asar2525]

Zebrafive, trust me I would LOVE a nice, new heavy duty brush hog but that certainly isn't in the budget right now.

To everyone else, I may end up torquing it down then match drilling a hole through the nut and bolt and putting a cotter pin through that. Thoughts?

 

[countrybumpkin]

This is what the sidewinders I’ve had uses.

If you have a extra 3/4” of thickness to go through do you have full thread engagement in the nuts? Are you sure they are tight enough ?

 

[Zebrafive]

Drill your bolt, but get a castle nut, that will allow more options to "pin" when it is tight, most you can be off, to get the cotter pin in, is less than one flat of the nut. You should be able to tighten a little more and get it pinned.

 

[Fuddy1952]

With a castle nut and cotter pin it couldn't come off.
I had one crazy thought though. It sounds like when the blade hits something hard like a small tree, etc. is when that is when it spins the nut off. It's like it's backwards like you said the opposite problem most people have. Could it be (for example) from the factory it had left hand threaded blade shaft and was replaced with right hand?
Check that and be sure it's turning in correct direction with PTO.

 

[Asar2525]

Countrybumpkin, the nuts are fully engaged by about 1 thread.
Zebrafive, I'll measure the thread pitch tonight and try to find castle nuts. It looks like Fastenal has them.
Fuddy, I don't think there's any way the direction could have been reversed. It certainly isn't on my tractor. I will check tractor supply and see if the sidewinder bolts they sell are LH thread, that's a good thought. It is certainly hitting rocks/stumps/trees that the blades will come off.

 

[countrybumpkin]

Ok, I don’t think you’ll have enough threads then for castle nuts.

My guess is you’re just not getting them tight enough , or the lock washers are breaking and then the bolts are loose.

 

[Asar2525]

If I put a castle nut on I can take off the Nord-Locks which will give me ~1/4"

 

[countrybumpkin]

You could I guess, but the main thing the cotter pins do is a safety , they are not intended to keep the nut tight.

The torque specs for 1-1/8” nuts start at about 400 and go up to over a thousand depending on grade and thread.

 

[Asar2525]

I would say with the 4' of leverage I tightened them to an easy 500 ft lbs. I supposed I could throw a rock bar in the open end of the pipe and get to 1000 ft lbs.

 

[Hilbilly]

Maybe the nuts aren't coming off and the bolts are breaking. If that's the case you could try using grade 8 bolts.