Thread: Advice needed with making front recovery points – 110 County

G'day Edward, The tube section of the bullbar certainly looks strong enough for a recovery point. It's in line with the chassis rails which makes it ideal. How much difference is there in the diameter of the shackle pin and the tube section diameter. If it is only minimal it may be better to drill/file the tube section and use the proper shackle pin as using a bolt could compromise the rigidity of the bow shackle.

It might be worth checking how well the bullbar is mounted to the chassis as well, wouldn't want the whole bar coming off on you

TIM.

Thanks Bearman.

Originally Posted by Bearman

It's in line with the chassis rails which makes it ideal.

Yeah, which makes me think that's what the tube sections were put there for. But being too narrow to fit the pin puzzles me.

Originally Posted by Bearman

How much difference is there in the diameter of the shackle pin and the tube section diameter. If it is only minimal it may be better to drill/file the tube section and use the proper shackle pin as using a bolt could compromise the rigidity of the bow shackle.

From memory the shackle is about 22mm in diameter, so more than filing would be needed to fit the pin. I would have to cut the old tube out and weld in a larger piece. But yes something like that could easily be done.

Edward

Originally Posted by long stroke

It might be worth checking how well the bullbar is mounted to the chassis as well, wouldn't want the whole bar coming off on you

Thanks Tim.

Yep the bull bar is properly mounted with high tensile bolts.

Edward

Force = stress x area
F = 800 (assuming 8.8 bolt) x pi x (19/2)squared
F = 226,000N double this as youll be in double shear ~ 450,000N (45tonne if you must)

I reckon a 19mm HT bolt will just about scrape in as being strong enough
Problem may be the "fit" of a 19mm bolt within the bow shackle.

Bolts are strong, its what we do with them that counts.

Steve

Originally Posted by I Love My Landy!

G’day all,

I am in the process of trying to make some recovery points on the front of my 110 County for snatching and to connect a winch cable when using a snatch block. There doesn’t seem to be too many options with my bull bar, however I do have one idea that I would like to get opinions on please (I know there are many people on this site that know a thing or two about recovery points).

My bull bar (unknown brand) has two pieces of steel tubing welded into the front uprights (which is made out of 6mm steel plate) in line with the chassis rails (please see photos 1 and 2). The internal diameter of the tubing is 20mm which just a little too narrow to fit the pin from a 4.75 tonne bow shackle, so what I am thinking of doing is using a 19mm high-tensile bolt secured through the bow shackle instead. Is this an acceptable and strong way of using the bow shackle? Also, does this section of the bull bar look strong enough for this? I would make two recovery points and use an equaliser strap when snatching, but use only one when doubling back a winch cable.
Thank you in advance!

Edward

First up, the shackle pin hole in your recovery point needs to be in the vertical axis so as the shackle can swivel in line with the direction of pull, in the situation pictured the shackle body would be pulled sideways against the pin causing damage to the pin and shackle body. It is highly unlikely that that you would ever have a straight line of pull in a real life situation, shackles are DESIGNED to ONLY be pulled in a straight ahead line.
You often read that you should undo the shackle pin a half-turn from fully locked so that the pin will be easy to undo after a pull, this is because the shackle body can distort if pulled off centre. With the shakle pin in the vertical axis the shackle body can align itself with the direction of pull and no undue stress is placed on the pin or shackle body. Repeated use of shackles with the pin in the horizontal axis will eventually lead to failure of the shackle.
If you use a bridle strap for winching or snatching, use the longest possible strap/cable/sling to keep the angle formed to well below 90 degrees preferrably below 45 degrees, Regards Frank.

A quote from page 70 of the Riggers Guide re: Shackles

"Shackles are designed to take vertical forces only. Diagonal forces will strain the shackle and lead to eventual failure."
Regards Frank.

Thank you Frank and Steve for your very informative replies.

Originally Posted by Tank

First up, the shackle pin hole in your recovery point needs to be in the vertical axis so as the shackle can swivel in line with the direction of pull, in the situation pictured the shackle body would be pulled sideways against the pin causing damage to the pin and shackle body. It is highly unlikely that that you would ever have a straight line of pull in a real life situation, shackles are DESIGNED to ONLY be pulled in a straight ahead line.
You often read that you should undo the shackle pin a half-turn from fully locked so that the pin will be easy to undo after a pull, this is because the shackle body can distort if pulled off centre. With the shakle pin in the vertical axis the shackle body can align itself with the direction of pull and no undue stress is placed on the pin or shackle body. Repeated use of shackles with the pin in the horizontal axis will eventually lead to failure of the shackle.
Regards Frank.

Originally Posted by Tank

A quote from page 70 of the Riggers Guide re: Shackles

"Shackles are designed to take vertical forces only. Diagonal forces will strain the shackle and lead to eventual failure."
Regards Frank.

Frank, your explanation makes total sense. This did cross my mind, however I also thought that if the horizontal orientation of a bow shackle on a tow bar hitch receiver was acceptable (see attachment), then it might also have been acceptable in my application. Or is the tow bar hitch receiver based on poor design? (Perhaps the angle of pull from a tow bar hitch receiver is not usually excessive?).

Edward