Rotary Cutter bush hog gearbox rating & sheer pin vs. clutch

[pitt_md]

Ain't no flex to a rotary cutter blade - they're your basic blunt instrument, usually an inch or more thick. I too had a shear bolt rig before I went slip clutch. Never broke a shear bolt till I hit a horse blanket. The RC would hammer away at 50 pound rocks without batting an eye. But hit a horse blanket......!!! Fence wire will do it too.

//greg//

I guess this depends on the design of the rotary cutter. Greg_G is right that the blades won't flex BUT they piviot on some models so that when they hit something that just will not move they fold back. They will take a softball size rock and turn it into little chips if not shut down when you hit it

 

[SPYDERLK]

you guys that don't service your slip clutch much--could it be that you aren't seeing rust because your machines get regular exercise? What about those that cut weekly and occasionally skip a week?

BTW, how do you insure exact spring length? Tighten and then count turns to loosen?

Good point. Ours dont get exercise that much but they do incidently smack some pretty heavy stuff just about everytime they go out. This probably gives little slips and they self clean. Also, clutches are different. Mine have a grease fitting that I grease occasionaly. Dont notice the plates being greasy, but ya put it in the center and some probably gets on the inner edges of the plates. I only adjust mine when I detect slip using it - if its hot after hitting something its too loose. I set mine by dropping it into a pile of dirt. The tractor should stall promptly with just a little slip of the clutch/ heats but not much. Dont do this if the BH gearbox is rated below tractor HP. BH gearbox should be well above tractor HP for a trouble free setup.
larry

 

[SPYDERLK]

Ain't no flex to a rotary cutter blade - they're your basic blunt instrument, usually an inch or more thick. I too had a shear bolt rig before I went slip clutch. Never broke a shear bolt till I hit a horse blanket. The RC would hammer away at 50 pound rocks without batting an eye. But hit a horse blanket......!!! Fence wire will do it too.

//greg//

CHAIN.

 

[CDsdad]

you guys that don't service your slip clutch much--could it be that you aren't seeing rust because your machines get regular exercise? What about those that cut weekly and occasionally skip a week?

BTW, how do you insure exact spring length? Tighten and then count turns to loosen?

I measure. Clutch on mine calls for springs to be tightened to 1.1 inches.

SPYDERLK, thanks. I got a second opinion on my whine/squeal. Guy says he thinks it may be a bearing but not sure. Fortunately, it's still under warranty. He said I'd have it back in a few days and he'd know exactly what it was.

 

[greg_g]

you guys that don't service your slip clutch much--could it be that you aren't seeing rust because your machines get regular exercise? What about those that cut weekly and occasionally skip a week?

BTW, how do you insure exact spring length? Tighten and then count turns to loosen?

Nope, mine is used every few weeks, late spring to early fall only. The rest of the time it's parked in the pasture. Obviously I perform slip clutch maintenance before first mowing in the spring. Never ever had a need to do it more often.

As far as spring tension, my Eurocardan has an adjustment chart based upon how many PTO horsepower are turning the clutch. Mine is 40hp, so I find the spring length on the chart that's associated. I then use a simple 6" caliper to tell me when I've compressed each spring to the length specified for that horsepower.

//greg//

 

[Farmwithjunk]

you guys that don't service your slip clutch much--could it be that you aren't seeing rust because your machines get regular exercise? What about those that cut weekly and occasionally skip a week?

BTW, how do you insure exact spring length? Tighten and then count turns to loosen?

Mine get almost constant use during the summer. One mower/tractor logged over 1400 hours last season.

6 months out of the year it gets ZERO use.

 

[coffeeman]

I guess this depends on the design of the rotary cutter. Greg_G is right that the blades won't flex BUT they piviot on some models so that when they hit something that just will not move they fold back. They will take a softball size rock and turn it into little chips if not shut down when you hit it

That folding back of the blades seems to be what my Woods BB840 does. Also, I have broke out the owners book. It does mention; check the slip clutch each season. Under trouble shooting, they mention a sheer pin in some models. It looks like I have a slip clutch though. I didn't see anything mentioned about the blades folding back. However, I remember looking under cutter after hitting a stump and stalling tractor. At least one of the blades were folded back, if my memory is right. By the way, I haven't checked my hogs clutch for 3 seasons and I guess I'm just lucky I haven't busted anything.

I wonder, why couldn't we cover clutch with some waterproof spray of some kind, at end of season? It might not help though as we still would probably want to check clutch anyway. It's a shame that the folks who make these machines haven't solved this problem. They have made brush hogs for a long time now; it shouldn't be rocket science.

Cheers....Coffeeman

 

[civesnedfield]

I wonder, why couldn't we cover clutch with some waterproof spray of some kind, at end of season? It might not help though as we still would probably want to check clutch anyway. It's a shame that the folks who make these machines haven't solved this problem. They have made brush hogs for a long time now; it shouldn't be rocket science.

Cheers....Coffeeman

The new Woods models come with a plastic shroud around the slip clutch. Now lets be honest, how many people found it a pain in the you know what, when adjusting the slip clutch or doing maintence, and just took it off. If it was left in place it would probablly help to keep the weather out.