Thread: Rear recovery hook

Originally Posted by Tank

Dougal using a thin plate, as you describe, will concentrate the load over a very small area which at worst will bend the pin and cause it to fail, or gouge a groove in the pin which renders it unsafe..

I agree that it will give point loading on the pin and wear both the pin and plate, but I consider this a lesser evil than the scenario below.



Using a rotating shackle mount would get around this problem and be the best solution. But I haven't seen any for sale as recovery items.

So it may be better to redrill the section that goes into the drawbar reciever at 90 degrees so the shackle sits vertical thus allowing for more severe sideway pull and less angle for the horizontal pull.
cheers
blaze

Originally Posted by Tank

What height difference are you talking about, are you trying to snatch up a vertical cliff face. The correct alignment of the shackle is crucial if you dont want to break or damage the shackle.

I wasn't talking about anything specifically and certainly not a cliff face, merely suggesting that it seemed more likely you could control the alignment of the two vehicles horizontally but that was harder to do vertically - say on a beach where someone has tried to get off, gets bogged and someone on hard sand pulls them out, there could be a reasonable height difference - but when does this become significant? or does this only become an issue at greater angles? just interested to know if I should re-drill mine. It seems a lot of these are sold with the shackle pin horizontal?

Andy

I see merit in drilling another hole for when the other location is a better fit.

My receiver pin had significant wear and the holes were elongated from a previous owner towing a horse float, so I have re-drilled the holes to 3/4" and use a quality 3/4" tractor pin. I would imagine that this pin would be plenty strong enough for recovery operations. Opinions?

Hey Dougal - thanks for all the interesting info. Much appreciated, especially your full colour stress pictures.

Back on snatching via a pin, what if you put a good sized sleeve over the pin, so the diameter went up from 16mm to (say) 20mm or something.

All you'd have to carry would be a small 2" length of tube, and then insert it in the strap loop before you put the pin through.

Whould that change most of the forces to shear, instead of trying to bend the pin?

Thanks
David

Originally Posted by POD

My receiver pin had significant wear and the holes were elongated from a previous owner towing a horse float, so I have re-drilled the holes to 3/4" and use a quality 3/4" tractor pin. I would imagine that this pin would be plenty strong enough for recovery operations. Opinions?

19mm is 67% stronger than 16mm (1.67x as strong). If the material is the same.
I still wouldn't snatch from it, but it's certainly better.

Originally Posted by spudboy

Hey Dougal - thanks for all the interesting info. Much appreciated, especially your full colour stress pictures.

Back on snatching via a pin, what if you put a good sized sleeve over the pin, so the diameter went up from 16mm to (say) 20mm or something.

All you'd have to carry would be a small 2" length of tube, and then insert it in the strap loop before you put the pin through.

Whould that change most of the forces to shear, instead of trying to bend the pin?

Thanks
David

Everyone loves pictures.

Yes, that would do a similar job to the receiver in spreading to load to the pin edges in shear, but will be a lot more fiddly to get in place. I guess the risk of chaffing the strap on the tube corners remains as well as the strap pulling right to one side.

I haven't got time to crunch all the numbers now, but considering it's got a 16mm hole through it, your sleeve would want to be bigger than 30mm, which doesn't leave much room to get a strap around it.