Shear pins (was Re:[AT]AllisChalmersB-1lawntractor

[Ralph Goff]

----- Original Message -----
From: Cecil E Monson <cmonson at hvc.rr.com>
To: Antique tractor email discussion group <at at lists.antique-tractor.com>
Sent: Thursday, July 15, 2004 4:45 AM
Subject: Re: Using tractor driven tillers (was
Re:[AT]AllisChalmersB-1lawntractor



> My experience with shear pins is that they work best on slow
> turning machinery. I've broken lots of them on my post hole digger which
> I run as slow as the tractor will idle. Seems like as soon as the hole
> gets 16" - 18" deep almost any rock will bind it up and stop it and the
> pin breaks like butter. I don't buy shear pins at all and prefer to use
> 1/4" or 5/16" cap screws in it. I just put a handful in the tractor tool
> box and don't worry about it.

My earliest memories of shear pins goes back to the early 60s when the
neighbour (Mr. F. ) came along each haying season with his Cockshutt 40 and
New Holland 68 baler to bale hay for my Dad. Broken shear pins were
commonplace it seemed. Maybe the plunger knife needed a little sharpening or
possibly the hay was just not quite ready to bale. Or just pushing that
baler a little too hard will do it too.
Most of the time I find that the shear pin will work loose and then break. I
sometimes will stop and re-tighten it several times. Even install lock nuts
sometimes but somehow the pins (5/16 bolts) always seem to loosen up and
then break.
Same thing on the 6 foot McKee snowblower. That shear pin is meant to
protect the drive train from the shocks of rocks, blocks of wood, lumps of
frozen cow manure, etc, although its surprising how many objects do find
their way between the fan blades and become a dangerous projectile.
I don't plan to leave the yard without a supply of spare shear pins (baler
or snowblower.)

Ralph in Sask.