Right! I've been mucking around sticking a winch on the front of my truck and I've had a problem. I haven't had a lot to do with winches etc. and would bet there're others out there in a similar pile o pooh.
Nowhere could I find what the factory shear pin size is. Even me old mate down the road thinks his 5mm pin is standard -- and then of course there're the guys that just go the high-tensile 6mm bolt way...
For anyone who hasn't run across shear pins, they are a built-in "safety valve" for the winch mechanism, designed to shear off and halt the drive when you've overloaded things. It 'helps' prevent breaking the winch rope, or breaking PTO gears, or even ripping the PTO off the transfer case (if your're really keen). Because of their function, it is imperative to at least show them a little respect.
Some guys are no doubt quite capable of the calculations and design necessary to ramp up the loading and stress on their equipment but I just wanted to start conservative and go from there. So I bought a factory pin for $22.50!!! to find out for sure what size it is supposed to be. Of course, I still have to estimate the material to make it from but to keep it simple I'm using a turned-down 5mm grade 12 capscrew (because someone I know uses this grade). The diameter of the factory pin is approximately (I'm told I'm half blind) 4.22mm (yeah, changed a typo)!
Anyone got actual figures on the shear strength of the different bolt tensile grades?
This will easily drag my moderately loaded BJ70 on 33" mud tyres along fairly flat, dry, grassed, hard-pack (heaps of traction) with all four wheels locked up. My mate, with a wobbly 5mm pin through a loose-as UJ has one one occasion dragged his LWB 60 on 31" roadies along dry tarseal with all the wheels locked up (trying to rescue a poxy two-wheel-drive truck from a paddock). I figure if I ever needed more pull than that, I'd go to a double-purchase anyway.
Hope this helps -- it would have been great for me a couple of weeks ago and at least I've saved you $22.50 ex-bloody Toyota!!!!
Factory Toyota PTO Winch Shear Pin
Factory Toyota PTO Winch Shear Pin
Last edited by Cutbak on Sat Sep 22, 2007 7:59 am, edited 2 times in total.
Good thread.
Wouldn't a grade 12 cap screw be to strong?
I run a nissan which has two shear pins of 8 mm dia.
One at the PTO box (which I run a M8 grade 8.8 bolt).
The other at the winch (which is easier to get to, to change out on the track), I run a M8 grade 4.6 bolt.
I would be interested to know what everyone else runs, as we all know at $22 you wont be replacing the pins with genuine parts.
Wouldn't a grade 12 cap screw be to strong?
I run a nissan which has two shear pins of 8 mm dia.
One at the PTO box (which I run a M8 grade 8.8 bolt).
The other at the winch (which is easier to get to, to change out on the track), I run a M8 grade 4.6 bolt.
I would be interested to know what everyone else runs, as we all know at $22 you wont be replacing the pins with genuine parts.
My cruiser had no pin when I got it.
I spoke to Just Cruisers in Southbrook and they recommended using a low tensile bolt (high tensile too strong). I also have heard that the std Toyota ones are too weak and they recommend drilling out the hole a little to fit a slightly larger one in. This does make sense if using a bolt as there is the thread to compensate for.
Since I had no pin and was heading away for a weekend I slotted in a 4" nail. They are a neat fit. I was unsure exactly how it would work but figured it would err on the weak side. Some one said it would be way over rated.
That weekend I got stuck in some mud and managed to break about 3 nails (thought they must be way too weak) before I realised I wasn't going to get any where while pulling off a solid tree with my diff against a stump!
Since then I have pulled that Hyundai Tuscon out of the Ashley on a 4" nail. That was pulling me forward so had to hold brakes and dig into the shingle.
Just the other day I tried pulling a MU out of mud, after three snatch attempts I tried winching and snapped the nail, but I think he must have been fairly stuck.
In summary, I don't know if I should recommend 4" nails but
1. They are plentiful esp if you need one on short notice.
2. They are cheap
3. The break before doing damage
4. They are strong enough to drag my cruiser through shingle with my brakes on and pull a soft-roader full of water up out of a swimming hole.
Still think they are underrated tho.
I should get round to getting some thing else I guess.
I spoke to Just Cruisers in Southbrook and they recommended using a low tensile bolt (high tensile too strong). I also have heard that the std Toyota ones are too weak and they recommend drilling out the hole a little to fit a slightly larger one in. This does make sense if using a bolt as there is the thread to compensate for.
Since I had no pin and was heading away for a weekend I slotted in a 4" nail. They are a neat fit. I was unsure exactly how it would work but figured it would err on the weak side. Some one said it would be way over rated.
That weekend I got stuck in some mud and managed to break about 3 nails (thought they must be way too weak) before I realised I wasn't going to get any where while pulling off a solid tree with my diff against a stump!
Since then I have pulled that Hyundai Tuscon out of the Ashley on a 4" nail. That was pulling me forward so had to hold brakes and dig into the shingle.
Just the other day I tried pulling a MU out of mud, after three snatch attempts I tried winching and snapped the nail, but I think he must have been fairly stuck.
In summary, I don't know if I should recommend 4" nails but
1. They are plentiful esp if you need one on short notice.
2. They are cheap
3. The break before doing damage
4. They are strong enough to drag my cruiser through shingle with my brakes on and pull a soft-roader full of water up out of a swimming hole.
Still think they are underrated tho.
I should get round to getting some thing else I guess.
Sold my 1985, BJ74 MWB Landcruiser, rear locker, 33" MTs, snorkel, PTO winch, solid bars all round, spotties, AM CB etc.
Now just a 1994, 1kz Surf, pretty standard.
Now just a 1994, 1kz Surf, pretty standard.
Thanks for your comments. It's all good. If only nuclear power station designers thought this much about their little design problems.
It's all a fine balance I guess, between bustin' something big, and having to spend the night somewhere wet and cold, or bustin' something small and being able to fix it so you can spend the night somewhere ... and wa... arrr... mmmm... yeah. Also, it's easier carrying a spare pin than a spare winch.
It's all a fine balance I guess, between bustin' something big, and having to spend the night somewhere wet and cold, or bustin' something small and being able to fix it so you can spend the night somewhere ... and wa... arrr... mmmm... yeah. Also, it's easier carrying a spare pin than a spare winch.
A few years back. I made up a few Nissin shear pin's, The owner used a Bital testing guage to check the type of steel. The pin was under cut with a parting tool , to a given size , at the point where they would shear. This stops the sheared part from burring the shaft.
This worked out a lot cheaper by the dozen.
This worked out a lot cheaper by the dozen.
"Oldblue" Electric to Manual Hub Conversion's 03 5447586
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mudlva
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a standard nail is reasonabily hard but it is not high tensile. its quite easy to check, a hack saw cuts a standard steel nail or bolt with little problem but a high tensile bolt or nail is a lot harder. and it only scratches a ramset nail. i have destroyed many a sabresaw blade trying to cut ramset nails off underneith timber plates were as a 4" nail the blade cuts off very easy
cheers
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