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Are 4 bolts enough to hold on a winch bar?
Posted: Fri Nov 10, 2006 8:09 am
by Emo
or am I mising something? I bought a second hand winch bar from eBay and it has two horizontal holes on each side to bolt to the chassis rails.
Is this enough? Seems like it should have more somehow.
Posted: Fri Nov 10, 2006 8:29 am
by Surfin Alec
My 80 series ARB bar has 4 bolts for the winch and 6 bolts per side for the chassis attachment. 2 under the chassis, 2 on the side and 2 on top of the chassis.
Posted: Fri Nov 10, 2006 8:35 am
by toughnut
Yeah 4 bolts are enough to hold on the bar

Just don't try and winch with it

Sounds like they haven't drilled out all the holes. I'd have at least 2 more bolts for peace of mind. I've run my comp truck with only 6 bolts with no probs but I'd feel uncomfortable with only 4.

Posted: Fri Nov 10, 2006 8:50 am
by Emo
Surfin Alec wrote:My 80 series ARB bar has 4 bolts for the winch and 6 bolts per side for the chassis attachment. 2 under the chassis, 2 on the side and 2 on top of the chassis.
That's what I thought a winch bar should have.
I might have to look and see if I can drill some more and / or get some extra brackets welded onto the bar.
Posted: Fri Nov 10, 2006 9:39 am
by Reddo
you could always send it back.....
Posted: Fri Nov 10, 2006 10:12 am
by Emo
Reddo wrote:you could always send it back.....
Nah, I only paid $80 for it. I'll get some extra brackets welded onto the bar so it can bolt through the top and bottom of the chassis rail as well I thinh.
Posted: Fri Nov 10, 2006 10:48 am
by Loanrangie
Emo wrote:Reddo wrote:you could always send it back.....
Nah, I only paid $80 for it. I'll get some extra brackets welded onto the bar so it can bolt through the top and bottom of the chassis rail as well I thinh.
If there isnt holes already you will need to add crush tubes to the extra bolt holes.
Posted: Fri Nov 10, 2006 12:28 pm
by ISUZUROVER
How big are the bolts??? A 12mm Class 8.8 bolt has a Tensile strength of about 15 tonnes, and about 10 tonnes in shear.
Posted: Fri Nov 10, 2006 1:57 pm
by N*A*M
ISUZUROVER wrote:How big are the bolts??? A 12mm Class 8.8 bolt has a Tensile strength of about 15 tonnes, and about 10 tonnes in shear.
michelle managed to sheer 2 of these in one go. they were 2 days old with nordlock washers too. i would beef up your mounting system.
Posted: Fri Nov 10, 2006 2:32 pm
by Emo
From having a chat with HSV Rangie who is a structual engineer, 4 x class 8.8 bolts with hardened flat ground washer to inside of chassy rail and nyloc nuts of same grade or higher will be fine.
Posted: Fri Nov 10, 2006 2:44 pm
by bazzle
Emo wrote:From having a chat with HSV Rangie who is a structual engineer, 4 x class 8.8 bolts with hardened flat ground washer to inside of chassy rail and nyloc nuts of same grade or higher will be fine.
1 bolt is fine too it just depends on what size it is, what way it is stressed etc.
10mm is 33.7 kN proof and 46.5kN breaking load for a new bolt.
Of course if it is mounted so it flexes angularly ie, chassis bends, loads must be lower.
Bazzle
Posted: Fri Nov 10, 2006 2:46 pm
by Emo
bazzle wrote:Emo wrote:From having a chat with HSV Rangie who is a structual engineer, 4 x class 8.8 bolts with hardened flat ground washer to inside of chassy rail and nyloc nuts of same grade or higher will be fine.
1 bolt is fine too it just depends on what size it is, what way it is stressed etc.
10mm is 33.7 kN proof and 46.5kN breaking load for a new bolt.
Of course if it is mounted so it flexes angularly ie, chassis bends, loads must be lower.
Bazzle
The 4 bolts will be 12mm.