Bolting in Mini-cage

[RCP Phx]

For now on my Cheromache project Im starting with a B-pillar hoop(and crossbar for belts).It will have 2 horizontal top bars that will penetrate the rear bulkhead to the rest of the rear cage.ANYWAY,for the b-hoop Im thinking about using a single 3/4" bolt to attach it from below.The B-hoop plate would be 1/4" thick and about 4" around and have an extended nut welded on with the hoop welded over that.
I want this to be removable(still thinking about the bulkhead)
If that made any sense,does it sound strong enough?

 

[et89xj]

You would be better off running four 3/8s" bolts then that one 3/4 bolt. Your mounting plate needs to be larger around 8"+, the best way is to sanwitch the floor with two 8" plates held by four 1/2" grade 8 bolts or eight 3/8s" grade 8 bolts. Thats still not the best but will give you a lot more sheer load then that 3/4 bolt. The best would be to weld the cage to a plated frame...andy



Good looking 2dr chop by the way...

 

[RCP Phx]

Tear thru isnt even an issue.The rockers have been designed to pick-up this point.They are boxed and tie to the framerail,the front of the leaf spring pocket and the leaf spring bolt.For the roll bar Im using 1-1/2"x.125" Seamless DOM,I dont know the stats on the welded strength of that,but I think the bolt is at least equal if not stronger.
Have you read Bill Vista's thread on hardware?
http://www.pirate4x4.com/tech/billavista/NutsandBolts/index.html

 

[RCP Phx]

Uh Oh,I hope we havent finally found a question that cant be answered on .
Btw,I heard this same concept is used on the factory TJ roll-bar?

 

[Mr.OverKill]

Uh Oh,I hope we havent finally found a question that cant be answered on .
Btw,I heard this same concept is used on the factory TJ roll-bar?

sounds strong enough, but like was stated before, it would be better if you used multiple fasteners to distribute the load more evenly. the single bolt would tend to work loose or wear the hole easyer ( make sence? )

 

[MaXJohnson]

I think the question is "what do you gain by going to the single bolt design?"

 

[Dirk Pitt]

the best way is to sanwitch the floor with two 8" plates .

I would recommend going with different size plates inside vs. out to avoid creating a shear plane.

If you use a 8" on one side (inside) use a 6" on the other (outside).

 

[MaXJohnson]

IMO, staggering the size of the plates is of dubious benefit. You'll get more mileage out of grinding a 1/2" radius or so on the corners of the plates and bevelling the edges that will end up closest to the sheet metal. I would also put the plate in a vice and tap each corner to put a slight bend in it.(bending away from the sheet metal)

 

[RCP Phx]

I think the question is "what do you gain by going to the single bolt design?"

A couple reasons.1-Im only doing this to stiffen the chassis due to my chop job.There will be another rear hoop(exterior) and a pre-runner style cage that also ties to the bumper and somewhere over the axle.2-Because of the location of the B hoop and where it lands over the spring pocket,space and access is an issue.

 

[MaXJohnson]

what is the bulkhead that you referred to in your original post. Are you welding in a panel from side to side behind the seats? Capped off on the top, that or closing in the rear (ala goatboy&beezil) would help alot. If you expect to add stiffness with a cage, an X midship, somewhere between seat backs and rear wheelhouse will do wonders(with or without the b-hoop) Tie it into the floor and to the upper structure. A b-hoop isn't going to help much if it is only attached to the floor and braced to rear-only cage structure.

 

[RCP Phx]

Im completely enclosing it(the equivalent to the back of a comanche cab with a sliding window but homade).I may do more later when I get this thing running again.This is the closet pic I could find(of the exterior/not the tie to the B pillar hoop) that shows what Im trying to do(for now at least).Keep in mind the ext roll cage will be just below the roof line and because mines a 2dr I"ll end up with a 40" deep bed area,so the whole thing will look alot flatter/longer.