From: Ken Boge (ken@clovermachine.com)
Date: Tue Dec 30 2003 - 08:32:42 PST
My $0.02 worth regarding shear pins:
The standard shear pin for the front winch on a M35 is P/N 7538740. It is
9/32 diameter by 2-3/8 inches long. Without a copy of the drawing for this
part it is not possible for me to tell what alloy of aluminum it is made
from. But looking through some mill catalogs for aluminum mill products, I
would guess that it is 2011-T3 which has a shear strength of 32,000 psi (the
only alloy commonly available in 9/32 diameter). Much of the aluminum sold
in hardware stores is alloy 6063-T3 commonly used for ornamental
applications. It has a shear strength of about 17,000 psi and is not
usually available in 9/32 diameter. Using this in 1/4 inch diameter in
place of the standard shear pin would result in a shear strength of less
than half.
Bear in mind that my original supposition that the standard shear pin is
made from 2011-T3 aluminum is based solely upon its common availability in
9/32 diameter. This does not preclude obtaining other alloys in this size
on special order.
If anyone wants to persue this matter, I would suggest calling Garwood and
speaking to an engineer familiar with these winches.
Ken
----- Original Message -----
From: "Michael P. Maynard" <mmaynard@rochester.rr.com>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Tuesday, December 30, 2003 7:50 AM
Subject: [MV] M35 Winching Questions
> Don't ya just love all my questions??? ;-)
>
> So I messed with the winch last night, was pulling a tree up the hill.
> Was working great. But being that I was pulling at a slight angle all
> the cable was winding on one side of the drum. Well with the
> convenience of the controls in the cab and dad down watching the tree,
> neither of us saw it happening until it was too late.... the cable
> overwound on the one side, bound up, and snapped the shear pin. Now I
> have around 100' of cable out of the winch, and no way to drive it!!!
> LOL Any ideas on how to prevent this in the future? I cant imagine that
> it is all that possible to steer the cable when a load is on it. I also
> wonder if I can find a mirror to hang out over the front to watch it
> from the cab... ;-) So what exactly is the shear pin? I really need to
> come up with some, and I know I can buy them. But I would also like to
> be able to use the winch in the mean time. I know they are aluminum,
> but is it a specific grade? Or is 6061 t6 ok? What is the diameter of
> the pin? And the length. Is it hollow? If so, what is the ID.... are
> they press fit? Or is there something that keeps them from sliding out?
> Interestingly enough, I couldn't find any remains of the pin last night
> other than little shavings....
>
> Well for what its worth, we hauled a healthy load of black locust
> firewood out of my uncles orchard last night (was on the side hill
> between orchards). My other uncle that lives nearby said he was pretty
> sure that it wasn't a Mexican van he saw/heard coming down the side
> hill... ;-)
>
> As for my sparks, they seem to have gone away. I still need to pin
> point the excessive noise at higher RPM's. I figure the little driving
> that I am doing around the local orchard is helping me to diagnose it
> while having fun at the same time. :-)I wish I had an easy way to record
> sound on the puter, because I would record it for everyone to hear.
>
> I think that's it for today, maybe....
> Mike
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