Winch shear pin

[jasonjc]

Does any one know for shure what typ of aluminum it is????
I found a place that stocks 9/32" its 2011-T3
The next size is 5/16" in 6061-T6511???

If the 2011-T3 will work it's only $4-5 for a 6' pices

the 6061 is cheaper but I'd have to trun it down or ream the hole out to 5/16".

I can't see paying $4-5 for a 1 1/2" pice of aluminum when I can get 48 pices for the same price.

What do all y'all think???

Come on I know alot of you know alot more about metals and alloys then I do. So please speak up....

 

[spicergear]

I'd say a grade 5 bolt...but that's just me. I'm not much into 'fuses' like that. Personally I think the aluminum shear pin is for the situation where someone unfamiliar with the winching process doesn't disengage something and wraps the chain and hook into the winch. The pin *might* be there to shear before the winch destroys itself as it tries to swallow the chain or clevis past the bottom connecting bar and blow it out of the bottom of the case...as I've seen them do. ...but that's just my $.02---

 

[mangus580]

6061 wont hold up.....

Just buy the pins, and be safe.

 

[builder77]

2011-T3
Shear Strength 221 MPa 32000 psi
6061-T6511
Shear Strength 207 MPa 30000 psi

http://www.matweb.com/search/SearchSubcat.asp?st=sc&catid=352#nfm


I have wondered the same thing as raw metal is much cheaper.

 

[M543A2]

I have made my shear pins for years out of 6061 T-6 with good success. I would like to try the 2011, but have not sourced it since I have many rods of 6061 T-6 in my possession. I turn the rod down to size in my lathe. I have not had a situation where I thought they sheared below what I would want them to. If I shear a pin, I change my rigging and go again. If someone has a piece of an original pin, I can get it analyzed at a met lab for alloy match, but it costs $107 to do it.
NEVER NEVER NEVER use steel bolts as a replacement.
A major contributing factor to pins that seem to shear too easily is the condition of the holes in the U-joint and the shaft. If someone had used a steel bolt in it at some point and sheared it, the edges of the holes can be damaged. When the edges of the holes get deformed ("egged" or oval shaped ) a pin will shear more quickly. It seems at first thought that good sharp edges on the holes where they contact the pin while under load would cut a pin more easily, but that is not true. When the holes are deformed, the load exerted on the pin is not a direct shear. The egged out holes first bend the pin to conform to the deformed hole shape, and in so doing weaken the pin with the bending stress. This causes premature failure. I have corrected damaged pin holes on farm machinery and winches in several instances, and it corrected the problem of the pin shearing below expectation.
Also if the U-joint to shaft fit is sloppy, it will contribute to premature pin failure.
Regards Marti

 

[acetomatoco]

Jatonka@telenet.net sells shear pins... ACE

 

[cranetruck]

Good information Marti, thanks for posting!

 

[rdixiemiller]

The reason the military uses shear pins is because you can get very predictable results with an alloy pin. Remember, these trucks were designed to survive draftees. Someone who has a lot of experience with winching can get away with steel shear pins, your average Joe needs the shear pin.
Reminds me of the shear pins in outboards. One old man was always hitting stumps and shearing the pins. So, he put in a grade 8 bolt. He ran over stumps for a while, only damaged a prop blade. Then one day, he grenaded the lower unit on his motor.
His complaint? Shear pins were 2/$1 at the time, it was costing him $2 every weekend when he went fishing. So he saved $10 over a month or so, then did $375 worth of damage to the lower unit. This was 25 years ago, now it would be much higher.
When I get the winch on mine, I will use a soft metal shear pin. I'll probably use 5/16 aluminum bolts and nuts so I can clean up the holes in the pto shaft/yoke. I have used pto winches for years, so I feel comfortable with them. I would not recommend this to someone with limited winching experience.

 

[Crazyguyla]

I looked the composition of the shear pins for M35A2's compared to M35 A3's. A2's use an aluminum alloy shear pin, while A3's use a steel pin. Same winch, but the A3's have a Hydraulic motor instead of a PTO. just thought this was interesting info.

 

[rdixiemiller]

Interesting. Sounds like the military was worrying about some other part of the driveline. PTO is plenty strong, as is the tranny. I can't imagine tearing out the winch driveshaft, although I have done that on an old winch truck!

 

[Stretch44875]

The A3 hydraulic motor may have a pressure relief so it stalls out before anything gets damaged.

 

[spicergear]

The yoke off the PTO accepts a 1310 U-joint. Most V8 powered cars through the '60's and earlier had 1310 U-joints before upping to the 1350's for other uses. Heck the M715's stock run 1310's in the drivelines and there and I've wheeled hard on 37" Boggers with stock driveshafts. The pin has to be the weak link for safety sake though I won't use a soft one. I prefer a keyed shafts anyhow. Do what you're comfortable with all- Personally I think a 10,000# winch on a 13,000# truck that can be loaded into the low 20K's...now get that stuck and you better have a snatch block or right off the bat or by the #'s you should be popping aluminum pins right and left.

 

[rdixiemiller]

Personally I think a 10,000# winch on a 13,000# truck that can be loaded into the low 20K's...now get that stuck and you better have a snatch block or right off the bat or by the #'s you should be popping aluminum pins right and left.

I agree. The truck should have had a winch with 25K# capacity to be able to self recover in a sticky situation. Of course that would have been more expensive and heavier, so I guess it was a compromise.

 

[Recovry4x4]

It does have a 20,000# winch as long as you have the snatch block. 30,000# if you have two of them.

 

[cranetruck]

For self recovery, you would also be able to use the wheels.

 

[Boatcarpenter]

FM 20-22 139 pages of good reading!! Check it out. It's in our very own Tech. Manual section!!!

 

[builder77]

M543A2 when you have repaired damaged shear pin holes in the past what sort of repair do you do? I am guessing reaming it out or going up to the next size bigger.

 

[FreightTrain]

Don't forget there are 3 Mire factors that the Military Uses.Up to the hub,Hub to Frame,and Frame and above.To rescue a vehicle you have to use special calculations to figure out how many runs of cable you need.Also,the deuce W/W had a block and tackle as standard equipment.Why use a 20K winch when you can use a single pully and hook and make a 10K winch into a 20K winch.Or pully on each end and make it a 30K or a double pully on one and a single on the other and get 40K etc etc etc.Give me enough rope and pullies and I can pick up a deuce by myself.

 

[clinto]

Give me enough rope and pullies and I can pick up a deuce by myself.

::

 

[FreightTrain]

OK,someone hook me up with 56 pulleys and about 1140 feet of rope.14,000 lift using 250Lb of pull(I am 300Lbs but can't do a pull up so I guessed at 250Lb pull.Plus 57 runs of rope 20 foot each(gotta have room for rigging).