Winch Shear Pins

[gringeltaube]

...............
Also, if the holes that the winch shear pin fits through are wallowed out in size, you are never again going to get good service out of a shear pin. ............
-Chuck

If you mean shear strength.... I used to think the same until I did the testing:
The final torque value to breakage was about the same for a given material; pin fitted tightly into a cylindrical hole vs. same pin in an oversized, deformed hole.
Maybe its comparable to cut (shear) material with a sharp pair of scissors vs a dull one...?

G.

 

[stumps]

Hi Gringeltaube,

I have no doubt that the pin's shear strength in a carefully controlled one time experiment is nearly the same...

But,

I think you will find that shear pin longevity drops drastically with a wallowed out hole. The lost motion caused by the wallowed out hole lets the pin go to one extreme of the hole when you unwind the winch, and to the other when you wind with the winch. Each time it travels through the lost motion, the hole takes a hard whack at the pin, and the pin gets hammered thinner.

-Chuck

 

[gringeltaube]

Good point Chuck! I really didn't think about rocking the long lever back and forth x-times before applying ultimate torque to the point of shear...

But.... do we really see any significant torque in the opposite (reverse) direction, despite the force to overcome the band-brake???
And if so, would it really be an instant full load as to cause that "hammering" condition everytime we shift the PTO into reverse, especially if on the wind-in side the load (under normal working conditions) will increase gradually also???

Certainly it would be difficult to reproduce exact real working conditions during such a quick test...
At least with what we do know already, everybody can easily make- or have access to- "adequate torque-" replacement pins, cheap enough to carry at least half a dozen spares in the glove box, just in case...

Against your statement "if the holes that the winch shear pin fits through are wallowed out in size, you are never again going to get good service out of a shear pin"..., I say again that the max. torque we can expect from such a pin replaced and immediately put to service at extreme load (typically after the first one has sheared amidst a recovery operation) will mainly depend on material and diameter of the pin, not so on the hole's condition, according to my tests...

To all: drive and winch SAFELY!!
G.

 

[Ronbo]

If any one gets/ makes any pins as stated earlier please shoot me a pm .I'd buy 1/2 a dozen to keep on hand .. Thanks

 

[stumps]

Good point Chuck! I really didn't think about rocking the long lever back and forth x-times before applying ultimate torque to the point of shear...

But.... do we really see any significant torque in the opposite (reverse) direction, despite the force to overcome the band-brake???

Every time the PTO is unloaded (clutch in, neutral, whatever...), the entire drive chain relaxes. A loose pin will seek a neutral relaxed position in its hole. When the PTO again takes a load, the pin will move freely in the wallowed out hole, building up inertia, until it gets hammered when the slack is taken up.

This happens a lot in the Ag world where the costs of owning and operating machines are a major hit on a tiny profit line. The machines get run into the ground, resurrected by whatever means, and then run into the ground again. Shear pins seem to always get replaced with grade 8 bolts, or hardened pins, further wallowing out holes. If you ever go back to the proper shear pin, it gives up quickly.

-Chuck

 

[colsoncj]

Does anyone know the spacing between cotter pin holes? (trying to figure out spec on length of pin.)

 

[gringeltaube]

Total length is 2-3/8", c-c distance between holes is 2-3/16", hole diam. = 2mm.

G.

 

[colsoncj]

Perfect Information. Thank you.

 

[Hooty481]

What alloy of brass was used in the testing?

 

[Jakelc15]

Can this thread be locked?

There is a reason why everyone says to only use the Aluminium pin for the winch. Anything else will cause damage. If you need more pulling power, double, triple or quadruple the winch line. With 200+ feet of cable you can do that and not harm anything. Sure it may be a pain in the A for a long pull but I'd rather have to move my truck every 20 feet and reset my rigging than blow the side of my tranny out. Steel pins are unacceptable, brass pins are not much better, and aluminum pins have to be the right diameter and alloy. Brass shears differently than aluminum and is often not 100 percent brass.
I know it's your truck and your winch and you can do what you please with it but what we are saying is for your own good. No one wants to see your winch explode or any other horror story from using the wrong pin.

If you need the proper pin there are many places that sell them, from SS members and surplus dealers. They're much cheaper than a new transmission.
I have been making pins for my truck and a few others.
The proper pin is
.2810 diameter
2.375 long
2.187 between holes
.078 hole
2017T4

Please don't post anything else here. Make a new thread for winch issues. This was started in 2006 and is some great tech reading but if your peoblem isn't from 2006 than make a 2011 thread!

Rant over!
Thank You!

 

[Hooty481]

others posted here not to long ago and this is the thread where the guy did the testing. I didn't want to post a new thread and get bashed for not posting in this thread. The chart showed that brass and alumnium was back and fourth on the strength. I can get brass cheaper then alumnium and make them my self. If I have pee'd in your cheerios then I apologize.

 

[gringeltaube]

Hooty, its all right, you have a valid Q.; I wish I had the A. to that.... I mean accurate alloy specs of the brass rod I used. No chance, so far...
I could send you a sample if you want to have it tested it in a lab?

Yes, I know that chart can be kind of confusing since I put all materials and results together, organized to increasing strenght, only.

G.

 

[Stretch44875]

Please keep shear pin comments in this thread, and do not start a new one. Lots of good info here, feel free to add.

 

[wilber]

Those of you that have broken winches, were you pulling a lot of rpm's or closer to an idle. I have a 20,000 garwood on my deuce but haven't used it

I spent my life around winch trucks in the oil field and never broke a winch. We never had shear pins. Snapped a winch line or two, but never ruined a winch or a truck frame.

We just let up when you could feel it getting too tight. There always seemed to be a point when you knew to back off.

 

[flyxpl]

Boy a guy gets chewed on for doing a search and posting in the thread he finds . If he would have posted a new thread he would get chewed on for not doing the search . I am glad you brought up this old thread , lots of good info .

 

[Jakelc15]

Stretch is right, this is the thread for shear pin related questions. Sorry for blasting down your question. This site is great for asking questions and the people here are helpful. I meant to be helpful and push the ''aluminium only''. Didn't mean to step on toes.
The type of brass used in the test doesn't really matter because it shouldn't be used. Brass is made of copper and zinc. Zinc is used to coat grade 8 bolts. Most brass you will find also has tin and other metals in it. You can buy all kinds of material that has the same shear rating but aluminum will shear with very little distortion to the yokes. We are all trying to get a long and happy life out of our trucks and would hate to see one go down from something as small as a shear pin.

 

[emr]

Doghead if u e mail me your address i will send u a couple of standard GI issue pins to test against the ones u got,,, RE

I winched a 30 ton switcher locomotive up a set of rails onto a flat bed low boy trailer, and she never sweated, not sure if that gives any idea of the shear pin, but its what saw one do , and still going....

 

[Recovry4x4]

I just buy surplus GI pins. I can write a check, mail it and in a week I have new pins. I don't need to be challenged to make something I can buy from home.

 

[stumps]

Stretch is right, this is the thread for shear pin related questions. Sorry for blasting down your question. This site is great for asking questions and the people here are helpful. I meant to be helpful and push the ''aluminium only''. Didn't mean to step on toes.
The type of brass used in the test doesn't really matter because it shouldn't be used. Brass is made of copper and zinc. Zinc is used to coat grade 8 bolts. Most brass you will find also has tin and other metals in it. You can buy all kinds of material that has the same shear rating but aluminum will shear with very little distortion to the yokes. We are all trying to get a long and happy life out of our trucks and would hate to see one go down from something as small as a shear pin.

You lost me here.

Are you implying that because brass contains zinc, and Grade 8 bolts are sometimes zinc plated that zinc is some kind of strong wonder metal that breaks winches?

The aluminum alloy that the milspec pins are made from (2024-T361) contains 93.5% aluminum, 4.4% copper, 0.6% manganese and 1.5% magnesium.

Should we infer from that, and the fact that manganese is used in some hard steel alloys that we shouldn't use milspec aluminum shear pins?

It really doesn't matter what your shear pin is made from, as long as it shears with the same number of kpsi as the original 2024-T361 aluminum pins.

-Chuck

 

[gringeltaube]

..........................................
It really doesn't matter what your shear pin is made from, as long as it shears with the same number of kpsi as the original 2024-T361 aluminum pins.