[AT] Adventures with shear pins

[jtchall at nc.rr.com]

To each their own, but I'm going to run whatever grade shear bolt the 
manufacturer built it for. Dad always taught me to buy a bushog by the HP 
rating of the gearbox. The IH dealer he worked for sold Hardee, folks seemed 
to have pretty good luck with them. Also, running stump jumpers is a great 
idea as well.

We have three rotary mowers here. All are old. The one with the most hours 
is a 3 blade Lilliston belt drive. Never been into the main gear box. No 
slip clutch, just shear pin. Over the years we've broke a few spindles. The 
belts probably slip and protect the gear box. No telling how many hours we 
have ran it. Wore out one deck, bought a used one and when it wore out we 
weled a thick sheet of steel over the whole deck.

Then we have a 2 blade Mohawk. It uses a slip clutch, but that’s not enough 
to protect the outer gearboxes. I can't remember if the center gearbox has 
ever been rebuilt, but those outer ones have a lot. We have to run it on a 
tractor that is almost too small to lift it in order not to tear out a 
gearbox. And this is just mowing grassy areas, not grinding up trees or 
clearing undergrowth. It's one of the worst pieces of equipment ever to come 
here.

Finally we have a single blade tow type Lilliston that is 50 years old. NO 
holes in the deck believe it or not. No slip clutch, just shear pins. The 
center gearbox has never been opened. My uncle used to make/maintain logging 
roads with it and a 90 hp Deere. Just an amazing machine.

John Hall