Winch Shear Pins - Page 7 - Steel Soldiers::Military Vehicles Supersite

cranetruck · 01-12-2009, 11:29

To aid your research, use the NSNs.

Jakelc15 · 02-01-2009, 16:24

Quote:

Originally Posted by gringeltaube

For do-it-yourselfers or the ones who can't buy them so cheap or aren't so close by....
I just did some comparative testing with my own creation of a "shear-pin cracker" (pat.pend.

) which actually worked better than expected.......

The OEM pins (including the broken core of my very 1st winch miss-hap...) snapped at about 160 ft-lb. More or less the same torque was needed for a home made one made of brass which I had used for years of "normal winching action" but later replaced when I found it with already some deformation.

Also I have a few larger ones of unknown application...(the M35 uses 0.279" x 2.125" measured inside cotter pin holes, these are 0.329" x 2.25") so I turned one down and it also took 160+ to shear it.

For comparison another "homemade" pin of unknown alloy but at least showing some temper... only resisted 100 foot-pound!

Next step will be trying to find 2024 or 2017 alloy locally and compare different levels of temper.
At least I know now what the goal is....

G.

By looking at your data above and I could be wrong but 160 lb/ft should yield about 45,000 psi shear strength. So you should be looking for 2024 in a t4 or t351 temper which has about 42,00 psi shear. The 6061 t6 only has about 30,000 psi and I recall reading that someone tried this for a shear pin and they thought it broke very easily. I am assuming that is a 3/4" bolt you are using since you have a 1 1/8" socket! I am also interested in making my own pins. My winch currently needs one and I have none. Would 5/16" round be what fits the M35 winch shear pin hole?

jasonjc · 02-01-2009, 17:57

If I remember right the pin is 9/32"

gringeltaube · 02-01-2009, 19:34

Quote:

Originally Posted by jasonjc

If I remember right the pin is 9/32"

That's correct. I measured some OEM at 7.10mm = .28", which is very close.

G.

m16ty · 02-02-2009, 01:29

I wonder if you can get 9/32 rod. Kind of a odd size. If not you could turn down some bigger rod but it would be alot easier if you could find the correct size and people could make them that didn't own a lathe. If I think about it I'll talk to my supplier and find out.

bottleworks · 02-02-2009, 02:10

Quote:

Originally Posted by m16ty

I wonder if you can get 9/32 rod. Kind of a odd size.

Would you settle for 1/4" 2024-T4? Only .030 difference.

https://speedymetals.com/ps-889-75-1...-aluminum.aspx

Jakelc15 · 02-02-2009, 09:36

Ideally you want the pin as tight as possible. So there isn't any "slapping" that could cause premature shear. But it would probably work just as well if you are gentle with it.

jasonjc · 02-02-2009, 10:07

I found the 9/32" rod before , I just don't rember the alloy. I will see if I can find the place again.

klawrence · 02-02-2009, 10:38

Found a site http://www.speedymetals.com

They only have 1/4" AL yet they do have 9/32 Brass round stock.

Jakelc15 · 02-05-2009, 20:55

A 5/16" bolt fits through the hole, anyone put a caliper on the yoke yet? Too cold for me today! Maybe tomorrow!