I want to build a Cage

[1990XJ4x4]

I am looking into building an interior cage in my 90 XJ, I was wondering what kind of tubing I should use, the only kind of tubing I have ever had any experience with is 1 3/8" .038 wall chromolly that we use on the mini Baja Car. I will be usin a MIG to put this together and I want to keep the cost to a minimum.

 

[Beezil]

I am looking into building an interior cage in my 90 XJ, I was wondering what kind of tubing I should use, the only kind of tubing I have ever had any experience with is 1 3/8" .038 wall chromolly that we use on the mini Baja Car. I will be usin a MIG to put this together and I want to keep the cost to a minimum.

go ahead and use HREW or DOM.

.120 wall, 1.5 or 1.75 dia is a good flavor

 

[1990XJ4x4]

Which one of those is lighter weight / less expensive / easier to work with?

 

[MaXJohnson]

I use 1.75" with a .095 wall thickness. Lot of guys use 1.5" @ .120 wall. Cost and strength should be very close on both of these. I haven't bought any tubing in over a year, so I can't give you an idea of cost.

 

[ROCKREADYXJ]

go ahead and use HREW or DOM.

.120 wall, 1.5 or 1.75 dia is a good flavor

Listen to B 1.5 and 1.75 is good I like to trow in 2.0 I have found it is cheaper than the 1.75 but do not go any thinner that .120 wall or you are asking for trouble. I prefer DOM tubing if money is no object you can use chromolly.

If you are not familiar w/ this kind of work let a profesional do it.Remeber thats you life in there.go build bumpers or rail or someother bs. leave the cage to someone who knows what they are doing it is not as simple as just bending some tubes.

 

[MaXJohnson]

Listen to B 1.5 and 1.75 is good I like to trow in 2.0 I have found it is cheaper than the 1.75 but do not go any thinner that .120 wall or you are asking for trouble. I prefer DOM tubing if money is no object you can use chromolly.

If you are not familiar w/ this kind of work let a profesional do it.Remeber thats you life in there.go build bumpers or rail or someother bs. leave the cage to someone who knows what they are doing it is not as simple as just bending some tubes.

I'm surprised that as a RockCrawler distributor, you didn't suggest solid stock. :laugh3:

Care to explain the trouble you are asking for???

 

[old_man]

How were you going to bend the tube? If you don't have a bender, why not get a kit. D&C Extreme have a pretty nice one for a reasonable price. You still get to weld it, its just prebent and cut for you. You could add some more cross bracing and some gussets to make it "yours". If I was going to do an internal cage, I would most likely start with theirs. It's a lot of work to figure out all the measurements and get it bent just right. You could end up wasting more tubing than the money you would save.

Not trying to talk you out of rolling your own, just letting you know that there are alternatives. There may even be other manufacturer's out ther that offer kits. I have seen the D&C and it is a pretty good design. I'm sure others can chime in and let you know about other kits.

 

[ROCKREADYXJ]

Care to explain the trouble you are asking for???

What is that a joke or an attack??

Don't know how to respond

 

[BrettM]

well since he said he used 1.75 .095 wall, he probably wants to know why you think he made the wrong choice. for something that's going to contact rock, I would definitely use .120 wall, but for an interior cage a larger diameter with a thinner wall will often be stronger.

 

[MaXJohnson]

What is that a joke or an attack??

Don't know how to respond

The three question marks would indicate that it is a question.

You said:

"do not go any thinner that .120 wall or you are asking for trouble."

What is that, a joke or an attack??

 

[ROCKREADYXJ]

Not so. If it was made from a stroger alloy of some type maybe. Most off road sporting events require .120 wall as the minimum for DOM and .085 for alloy type steel wich is really expensive.

Thats like saying well its od is 4 in so it must be strong enogh but its exhaust tubing. you know thats not strong enough rite? I dont know if I am make a good analogy? just trying to help

 

[ROCKREADYXJ]

The three question marks would indicate that it is a question.

You said:


What is that, a joke or an attack??

you have there a reference to solid stock and the comment about care to eplain the trouble You got me confused

Now I know what you are speaking about.

I would not use tubing with a thinner walll than .120 because the metal is to thin and it loooses all its strength. And the trouble I was refering to was a cage that could fail in the event of a roll.

 

[Beezil]

I could see a DOM cage being made out of .105 or .090.....absolutly

if the geometry was sound.

.120 is a good size to suggest ona forum like this, if yer lookin to write a few sentences instead of a couple pages...

 

[biscuitboy87]

i would go with seamless Nitinol tubing so that you can add electricity to it after a roll and have it spring back to shape...memory alloy.

actually, in case i didn't sound sarcastic and fun enough...it was a joke.
.120 * 1.50 or 1.75 tubing should work for you.
i like the weldability and added strength of 4130...but most would agree overkill.

 

[RCP Phx]

On a side note!I want to install a "B" pillar hoop before I re-attach the roof.Looking for some ideas on the lower attachment point.I would like to pick up the front leaf pocket at the same time?Any thoughts/pics?

 

[BrettM]

Not so. If it was made from a stroger alloy of some type maybe. Most off road sporting events require .120 wall as the minimum for DOM and .085 for alloy type steel wich is really expensive.

Thats like saying well its od is 4 in so it must be strong enogh but its exhaust tubing. you know thats not strong enough rite? I dont know if I am make a good analogy? just trying to help

no, this IS so. strength is gained by larger diameter. strength is lost by thinner wall. there is a point where the two meet and one passes the other.

I don't know where that exact point is, but to choose some safe numbers; I would wager that 2.5" .095 wall would be stronger in tension/compression and bending than would 1.5" .120 wall of the same steel.

 

[Beezil]

no, this IS so. strength is gained by larger diameter. strength is lost by thinner wall. there is a point where the two meet and one passes the other.

I don't know where that exact point is, but to choose some safe numbers; I would wager that 2.5" .095 wall would be stronger in tension/compression and bending than would 1.5" .120 wall of the same steel.

Interesting.

get to work.

I'd like to see some science on this.

 

[BrettM]

just think of it at the extremes and the principles become pretty clear.

"strength is gained by larger diameter"
-imagine a piece of .5 inch diameter .120 wall tubing. you could probably bend it by hand. now imagine a 3 inch diameter .120 wall piece. there is NO way you're gonna bend that by hand. the wall thickness stayed the same, the diameter increased, so did the strength.

"strength is lost by thinner wall"
-imagine a piece of 1" diameter .25 wall. you could NOT bend that by hand. now imagine a piece of 1" diameter .01 wall, paper thin tubing. you could bend it by hand. the diameter stayed the same, the wall got thinner, the strength was decreased.

that covers bending forces.

for tension, it is a function of the cross-sectional area of the steel. a larger diameter will increase the cross-sectional area, and a thinner wall will decrease the cross-sectional area.


Since both diameter and wall thickness influence strength there is a balance to be acheived. You'd have to get someone with the engineering books to figure out where that balance lies exactly.

 

[Overdriven]

Hey, I thought we school was out untill Monday. I just learned a ton. All the above info will help out when I do my exo. Thanks.

 

[Beezil]

just think of it at the extremes and the principles become pretty clear.

"strength is gained by larger diameter"
-imagine a piece of .5 inch diameter .120 wall tubing. you could probably bend it by hand. now imagine a 3 inch diameter .120 wall piece. there is NO way you're gonna bend that by hand. the wall thickness stayed the same, the diameter increased, so did the strength.

"strength is lost by thinner wall"
-imagine a piece of 1" diameter .25 wall. you could NOT bend that by hand. now imagine a piece of 1" diameter .01 wall, paper thin tubing. you could bend it by hand. the diameter stayed the same, the wall got thinner, the strength was decreased.

that covers bending forces.

for tension, it is a function of the cross-sectional area of the steel. a larger diameter will increase the cross-sectional area, and a thinner wall will decrease the cross-sectional area.


Since both diameter and wall thickness influence strength there is a balance to be acheived. You'd have to get someone with the engineering books to figure out where that balance lies exactly.

thats not science, thats an explanation. Didn't need it. I wanna find specs, charts, data. I'd like to see where the "crossover" is

have anything?