Mowing Bush Hog for Dummies

[Slowpoke Slim]

I agree with Willy on the bolt hardness.

No way would I use a grade 8 bolt as a "shear pin".

It will only "shear" after everything it's connected to is destroyed first.

I use plain old grade 2 bolts on my rotary mower. If I "find" something in the tall grass, that bolt breaks before anything else has a chance to get beaten on. I'd much rather replace a shear bolt than replace a gear box on a cutter. Or worse, something inside the PTO gear set.

 

[sallyb]

Hope these pictures can explain what I did to tiller

 

[Jstpssng]

I agree with Willy on the bolt hardness.

No way would I use a grade 8 bolt as a "shear pin".

It will only "shear" after everything it's connected to is destroyed first.

I use plain old grade 2 bolts on my rotary mower. If I "find" something in the tall grass, that bolt breaks before anything else has a chance to get beaten on. I'd much rather replace a shear bolt than replace a gear box on a cutter. Or worse, something inside the PTO gear set.

I believe that is what she is using. After making the comment about Grade 8 she said she went to TSC and bought shear bolts.
I know for a fact they sell grade II shear bolts there in packages of 5, as that's what I am using,

 

[WranglerX]

A grade 2 or grade 5 or grade 8 bolt would have same physical dimension that is why all will fit... The difference is the carbon contend and "shear" pressure in PSI required to actually shear the bolt to release its holding feature.... Same with metric bolts, but diameters and grade differ from SAE bolts...

Grade 2 >> 74,000 PSI, low carbon steel
Grade 5 >> 120,000 PSI, medium carbon heat treated steel.
Grade 8 >> 150,000 PSI, medium carbon alloy steel.

The package of 5 grade 2 shear bolts at TSC is probably more expensive than the grade 2 bolts bought by the pound in the bulk buy bins...

As the comment about "pushbutton release" comment was never answered (that I noticed) ..

Push button release is the method of how female end of PTO shaft locks the tractors male PTO shaft, quite common and probably not any sort of deal breaker (unless you dislike them) and it works well unless damaged...

 

[TheMan419]

As someone who is not totally a mechanical guy I prefer the shear pin. The slip clutch needs annual maintenance. If I were using the implement commercially I would think a slip would be better.

 

[G31]

My Razorback BH6 has a grade 5 shear bolt. I’ve broken one so far in a year and a half.

 

[ROUSTABOUT]

If you hit something that breaks a shear pin (which is really just a bolt and nut), you're done mowing until you replace it. Most people keep a supply of spares on the tractor somewhere to replace in the field.

If you hit something with a slip clutch, it just slows or stalls the blades as the clutch slips, then comes back up to speed as the clutch catches and reengages. You may or may not have to stop and restart.

We weld the slip clutches up solid. If it has a shear bolt, it gets a grade 10 in it. I do some gosh awful bush hogging too. If the front of tractor will bend it over, the back should be able to chop it up. Oldest tractor is 1981 model. Never any tractor or bush hog trouble. It has a leaking water pump now and will be the third pump since 1981, but unrelated to bush hogging use.