bull bar fish plates on chassis

[Wambat]

hey guys, got two main questions that i need to get some ideas other than my own for.

first one is to do with bull bar mounting on chassis rails,

the other week end i put a steel bar on to replace the bumper on my 75 series, and after i pulled off the bumper mounts, i noticed that at one stage the 75 must have had a bull bar that had been hit, as one bolt has pulled the chassis out maybe 5 mm, and there has been about 3 bolds actualy pulled out, one is sheared the other two look like the captive nut behind them have broken their welds.

so now there are only three bolts on one side and two on the other holding my bull bar on, which i dont like, specialy if i were to attache my recovery point to the bar, or for when i finnaly make a custom bar.

so what i have been thinking is to make up to flange/fish plats that i can weld to the sides of the chassis, which will be tapped, so that i can then make plates for the bull bar that mate up to them holes, the only problem i see from that is then having to drill the chassis for the ends of the bolts to clear, which would be awkward as i dont think it would be that easy to get the drill in there, specially on the insides of the chassis rails, the out side may be do able with a right angle drill maybe?? any other ideas would be highly appreciated...

and also having one of the plates extend beyond the front of the bull bar, or lower than it that i can put a shackle through to use as a recovery point, which leads me to my second question.

i know that we should never use a shackle to join two snatch straps together, but i have heard people mention here and other places that using them at either end of the strap is ok, i would like some real perspective on that please, before i go and make a bar that has loops for the shackle,

thanks guys.

alistair

[PJ.zook]

It would be best to consult an engineer, but if you did it properly you could weld two plates both sides of the chassis rails, then drill mount holes right thru the lot, then use bolts and crush tubes on the inside of the chassis to stop the chassis rails crushing when you tighten the bolts.


As for joining snatch straps with a shackle, you are correct, it should never ever be done, this is because its not the ubolt that breaks, its the snatch strap. Its all about stored energy. If you have a ubolt joining two snatch straps, and one of the straps breaks under tension, there is a shitload of stored energy both sides of the ubolt in that straps, which will send the ubolt flying at high velocity, which is dangerous for obvious reasons.
When you use ubolts at either end of the strap, there is no stored energy on the side that shouldnt break before the snatch, like youre recovery point, so if the snatch breaks, the ubolt isnt going anywhere. If the ubolt or recovery point breaks then it will go flying.
But you built youre recovery points strong enough... right?

[Wambat]

am playing this smat i mean smart... i havent made it yet, and am going to design it for the intended purpose, so instead of the three mm plate that is on the standard steel bar(tie down point not recover is how i see that) , it will be 10 - 12 mm plate, i may even go thicker for the plate with the hole for the shackle and 10 - 12mm for the bull bar mounting,

the trouble is there isnt a hell of alot of room on the chassis at the front of the 75, and having a few holes already useless dosent help, i may be able to get some of the shit our of the front of the chassis rails (it has steel that looks factory, as i saw it on the 75 i got my bull bar off), that is welded in there making it impossible to get to the captive nuts, so if i can get that steel out(die grinder or something) then i can mount plates on the inside too, and use them to tighten up on to, which would act like a big washer and crush against the chassis which would make it nice and firm. i could also weld nylocs to that plate so that i dont have to weld to my chassis, and if i pick up the original holes i dont have to drill my chassis either.

i think that might be the way to go, any one disagree with that?

Al

[PJ.zook]

10-12mm is a bit excessive, as the chassis holding it is only like 3mm either side. Weakest link in the chain...
As for what else u said, ive had too much to drink to understand that atm