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View Full Version : Shear Pins and shear-pin metal



hwingo
01-10-2014, 04:15 PM
Naturally shear pins are designed to break rather than bend. So, from what metal are shear pin made? I broke a shear pin on the blade of my snow blower. What metal can be substituted as a shear pin (and work .... provide protection) without having to wait for a new pin to arrive?

Harold

jeremy13
01-10-2014, 05:40 PM
My lathe has brass sheer pins. but being from Texas I have no clue what a snow blower can chew up.

duckman
01-10-2014, 05:55 PM
I would use a grade 3 bolt with grooves in it to give it a shear point, I repaired gear boxes that had Allen bolts put in good for me, bad for them.

Lew Hartswick
01-10-2014, 06:18 PM
Our Clausing/Metosa lathes use brass taper pins in both the lead screw and the carriage drive shaft.
Just had to replace one a couple weeks ago. Down to one spare now, will have to crank out some soon.
...lew...

barts
01-10-2014, 11:26 PM
All the pins that come up on google shopping look like cheap steel bolts... I'd go w/ duckman's suggestion.

- Bart

outlawspeeder
01-10-2014, 11:36 PM
If you have what is left of the bolt, get a shaft and a tube about the same size. Put it together and use a torque wrench to see when it breaks. Test two with various bolts to see when it lets goes.

Oh just use a grade 3 and take it easy!!!

flutedchamber
01-11-2014, 02:01 AM
I have a Craftsman snow blower from the sixties. It came with a spare shear bolt. It was a grade 2 bolt with a groove cut in it .060 deep, located where the shaft and sprocket met, which would be the spot with the most stress.

I've replaced the bolt with standard grade 2 bolts with zero problems, even tho they have no groove.

bob ward
01-11-2014, 04:31 AM
el cheapo hardware bolt

Rick Johnson
01-11-2014, 09:13 AM
I own and have owned two John Deere tractor mounted blowers that came from the factory with spare shear bolts. Both units were supplied with 1/4", grade 5 bolts with no undercut. You would probably be safe to use a grade 2 bolt until you can acquire a factory bolt for comparison. As an aside, in the Army, I operated a wrecker truck that had PTO driven winches at both ends. I had occasion to replace the shear pin for at least one of those winches, and it was a not so hard steel with an undercut.

cameron
01-11-2014, 09:27 AM
el cheapo hardware bolt

The el cheapo hardware bolt has pretty much disappeared around here. Grade 5, coarse thread, that's it, in hardware or big box stores.

More choice at fastener supply stores, but I don't think anybody bothers to stock Grade 2.

Quick temporary substitute for snowblower shear pins is a length of threaded rod with nyloc nuts. Not the high strength alloy threaded rod, of course.

firbikrhd1
01-11-2014, 11:31 AM
Shear pin material varies with the requirements. My outboard motor uses a stainless shear pin in the prop hub. Aluminum shear keys are used to retain small engine flywheels. I've seen brass shear pins in various applications as well as plastic shear pins. The material used depends upon the stresses involved in the operating unit and the materials the unit is made of.
My guess would be that the manufacturer has done extensive research and found the most appropriate shear pin material and if you stick with that you'll be safest.

hwingo
01-12-2014, 12:02 PM
Ok, I have purchased a Grade 2 bolt so I will fabricate a shear pin out of that (to include two evenly spaced .060" deep cuts). Just in case, and to have on hand as a emergency measure, I will fabricate one from brass as well.

Thanks guys for you thoughts and info.

Harold

krutch
01-12-2014, 03:02 PM
I've been using all thread for some time now to good effect. The pins for my blower are expensive and not generally stocked. I use crush thread nuts and so far they have worked just fine. Install one nut by the double nut (non crush thread) method and start the other nut on by hand to make a "set". Then when you need to replace, wrench the loose nut on and..... Walla!

hwingo
01-12-2014, 05:11 PM
I've been using all thread for some time now to good effect. The pins for my blower are expensive and not generally stocked. I use crush thread nuts and so far they have worked just fine. Install one nut by the double nut (non crush thread) method and start the other nut on by hand to make a "set". Then when you need to replace, wrench the loose nut on and..... Walla!

I might as well make one of those too.
Harold