m16ty

If someone will send me a pin they know to be mil-spec I can find out the alloy. I've got a friend that works at the local scrap yard and they have a gun they can "shoot" a piece of metal with and it will tell you the alloy. I'll have to destroy the pin though so don't expect it back. I'll have to flatten it out with a hammer to get enough surface area for the gun.

AL comes in a bunch of alloys with a wide range of hardness. 1100 being almost pure AL and the softest to some of the aircraft alloys that will give steel a run for it's money.

DanMartin

I believe the term is "shock load" which can be many times the static load on the machinery. I would say that the winch pin breaking under shock load explains 90% of the breakages referenced above. Taking up slack in the line, shifting load, quick engage/disengage. All of these will break parts if not relieved with some kind of a stress regulation mechanism.

There's a great book by Carrol Smith called "Engineer to win" mainly about the engineering of race cars, but he gets into the science and mechanics of parts failures (engine, chassis, etc), even down to the metallurgy level. A fascinating read for those interested...

__________________
Dan Martin
1988 M35A2C (USAF)
1945 M29C Weasel
Hillsboro, OR.
MVPA# 31124
MVCCO# 828

We shall not cease from exploration
and the end of all our exploring
will be to arrive where we started
and know the place for the first time
- T.S. Eliot

MUDLORD

the pin blowing out wont damage the universal. thats why the pin is there to begin with. the shaft will spin all day long under no load once the pin blows .

Floridianson

I might pull off the band brake cover and check that there is no rusting going on and that the band is well released.

avengeusa

if anyone knows the material they are supposed to be made from i could spin a bunch out on the lathe

docfarmall

so were is the best place to get shear pins then ???????

JohnnyReb

That is not always correct. The purpose of the shear pin is to protect the drive; however, if you continue to try and run the winch then the sleeve can bind up and blow the universal. This is from personal experience.

What will happen is that the UJ connection can work back and when it is about to fall loose it can bind at an angle.

m16ty

I'm thinking you could probably find some rod the proper dia. and not have to turn it down. Like I said before all I need is a pin and I can find the alloy.

rockman

I bought some NOS pins from Gene Pantano in CO 5 years ago and have not sheared one yet. I pull trees, dead corvairs and other things.

Bill

__________________
Bill
MVPA 21439
M35A2
"just glad to be here"

rockman

M16ty, I can send you one if you want.

Bill

__________________
Bill
MVPA 21439
M35A2
"just glad to be here"