On Sat, 05 Feb 2005 17:38:47 -0500, Nick Hull
wrote:

In article ,
"Harold and Susan Vordos" wrote:

"Nick Hull" wrote in message
...
In article ,
"Harold and Susan Vordos" wrote:

"Nick Hull" wrote in message
...
In article ,
"Harold and Susan Vordos" wrote:


On my farm equipment I use grade 8 bolts, they hold well and break
clean. Grade 2 and sometimes grade 5 smear at the break and are a
real
dog to get out.

Chuckle!! And if the grade 8 holds and the gear doesn't, how hard and
expensive is it to change the gear(s)?

Shear pins are generally supposed to be the weak link in a
circuit-------intended to fail before expensive components do. If
you've
been shearing grade 8 bolts and they're not undercut, you're one lucky
man,
unless your equipment is designed around the concept. Does the
manufacturer recommend the grade 8 bolts?

I'm using it on VERY old equipment, and the grade 8 bolt IS the weak
link; I shear one or 2 per year and nothinmg else has broken.

Interesting, considering the tensile strength of the bolts.

Tensile doesn't count, only shear.
Nick,
That's interesting, about using grade 8 bolts for shear pins. I wonder
how much different the shear strength is from grade 8 compared to
grade 5. On my old Ford 9N is an adapter on the PTO that has a ratchet
in it so the bush hog doesn't power the tractor when it's throttled
down. This device has in it a shear pin. When it broke the first time
I was surprised to see that it uses a roll pin, not a soft steel or
brass pin. Which real nice because it doesn't smear and jam up the
thing.
ERS