Newbie question on tubing

[killingthemonkey]

I've decided that I want to go full exo. I saw the thread on the price of DOM tubing and now I'm all confused. What are the differences in DOM, HREW, and erw. Thanks guys.

[fatkid]

HREW, hot rolled electric weld
DOM, drawn over mandrel (aka seamless)
I'm not quite sure how much the process increase the strength of the tube but it increase the price of the tube by about 3x's, I've heard about 10%.The only tube work that we've had to do in DOM is SCCA sanctioned rally cars. That's kind of why alot of people think it's not really needed.

Ask some of the metal guru's

[killingthemonkey]

Thanks, fatkid. Name some of the metal gurus now. I'm assuming you mean people on the board.

[fatkid]

Tin Bender is one

[Tin Bender]

Sorry, here's the long version.......

This grade of mechanical tubing is the fifth of six types classified in ASTM A513. Produced from steel strip by cold forming, electric resistance welding (E.R.W.) and cold drawing to finished dimensions, D.O.M. is the most versatile and widely sold mechanical tubing grade. With an appreciation for the product's flexibility, the reason for this is easily understood. D.O.M. can be produced with outside diameters as small as .125", as large as 15" and everything in between. The wall can be as thin as .010" or near .700" thick. Carbon chemistries range from A.I.S.I. 1006 to 1060. A variety of thermal treatments can be applied to alter the mechanical properties and machinability. The E.R.W. process guarantees the weld to be as strong or stronger than the rest of the tube body. The origin from flat strip results in a more concentric product than cold drawn seamless.

D.O.M. is used for a tremendous variety of machine parts where closer tolerances and higher mechanical properties are needed. Hydraulic cylinders, spindles, jacks, rollers, motor housings, elevators, air hammers, and shafts are just a very few of the applications utilizing D.O.M. tubing.

[Tin Bender]

"CDSM"...............

"Cold drawn" as it is often called, is the precision half of the ASTM A519 specification. Once the dominant type of mechanical tube in the market, cold drawn seamless now plays a reduced but still important role. While D.O.M. has replaced seamless in nearly all standard shelf sizes common to both products. Cold drawn seamless is produced by the piercing method. A heated billet moves through pressure rolls as it is driven over a stationary mandrel to produce a hot finished seamless tube. This hollow is then cold drawn through a die and over a mandrel to precision finished dimensions.

[Tin Bender]

4130 Tubing is often referred to as "Chrome Molly" tubing. This jargon term is derived from the chromium and molybedum concentrations present in the metal itself, which run in the area of .80-1.10 for Chromium and .15-.25 for Molybedum.
"Chrome Molly" tubing or 4130 Tubing is best for applications where a high strength to weight ratio is needed or desired. Typical tensile strength for 4130 is approximately 90-95000 PSI.
BUT a "drawn" tube OR "Welded" tube will offer a close 75,000-85,000 tensile.
AND with a ERW HERW you don't have to worry about Relieving your joints.



Now with that said, .250 wall is WAYYYYYYY overkill for a CAGE!!!! and HERW .120 wall is fine....

[Tin Bender]

Broken down version.........

moly is cool, but a BIG pain in the ass....

DOM is cool, but WAY to much $$$...

weld'd is PERFECT for make'n cages and stuff, just keep the seam inside the bend to be x-tra safe....

[Tin Bender]

Here are some more useless specs.....

ASTM A513 Type 1
Hot Rolled Electric-Resistance Welded (ERW) Carbon Steel Mechanical Tubing

ASTM A513 Type 2
Cold Rolled Electric-Resistance Welded (ERW) Carbon Steel Mechanical Tubing


ASTM A513 Type 5
Drawn Over Mandrel (DOM)

ASTM A513 Type 6
Drawn Over Mandrel Special Smooth ID (SSID DOM)

ASTM A512
Cold-Drawn Buttweld Carbon Steel Mechanical Tubing

ASTM A519
Seamless Carbon and Alloy Steel Mechanical Tubing

[Tin Bender]

Just let me know when to stop!!!!

*deep breath*


ERW pipe is made from strips of hot-rolled steel, which are passed through forming rolls and welded. While seamless pipe is traditionally stronger and more expensive than ERW pipe, ERW technology is improving and the technique now accounts for approximately 48% of annual tonnage shipments of oil country tubular goods

[Tin Bender]

SEAMLESS PIPE (SEAMLESS TUBE)
Tubular product made from a solid billet, which is heated, then rotated under extreme pressure. This rotational pressure creates an opening in the center of the billet, which is then shaped by a mandrel to form the pipe or tube.

[J-Dogg]

The metal guru has spoken......

[Tin Bender]

Can I stop now?

[DSI]

Originally posted by Tin Bender
Can I stop now?

nope, sorry

[bobaki]

a guy could get a education here thanks Mr Bender....

[fatkid]

Like I said,

[killingthemonkey]

Tin Bender,
Thanks for answering this newbies questions. Next one though. I have decided to go full exo. Also, I want to cut the back into a flatbed. Well, me and my room mate are having a disagreement on the diameter of tubing to use. I was thinking a full 2". He says 1 1/4" is good enough. Your thoughts?

[bobaki]

I was told almost the same thing,and was con vinced enough to buy the dies,now I just have to use them....

[Tin Bender]

Going exo is a big step.... It's alot of work but well worth it in my opion..

Frosty rolled twice on bald mount'n on LeRoys first trip out!!! (not flops, complete rolls) Just to "test" the new exo out. All I can say, is he drove it there on the HWY, and he drove it back home, windshield intact and the cage not completely finish'd... (it needed some 1-1/2 brace'n in the rear)

Why would you want to go with 1-1/4?? Your not give'n up more than an inch and a half in width so that wouldn't be it...
Your not give'n up much in the way of weight...
In my opion, 1-1/4 is WAY to small to LOOK good...
It's not as strong as 2"...

If 2" just seems to big, I wouldn't go ANY SMALLER than 1.5 x .120 DOM or 1.75 x .120 weld'd...

The most important thing is to remember to cross brace right behind the cab to the FRAME...(99% of "rolls" are sideways)

And gusset the A-pillars to help the front to bach shift..

DON'T build your exo to keep the body from get'n dented, build it to keep your head off the rocks

people do thing different and thats great!!! If everyone were the same life would suck!!!

[fatkid]

The 2" we used for the sammy took a hard hit before it was even done and it didn't even tweek in the slightest bit.

[killingthemonkey]

Thanks for the input guys. I'm going to bed now. Look for more newbie questions tomorrow or the next day.

[TNToy]

TinBendy,

You rock! What would you say are the most common flaws in an exo cage? not enough bracing for lateral rolls, not enough against front-to-rear forces?

I guess I'm asking... What are the things you almost always see WRONG with the exo-cages people do to their own rigs in their shop?

[Tin Bender]

IMO...... and it's just that..

I DON'T want to come across like some smart ass know it all, and if I have, i don't mean to...

It's something like "DRM phobia"

IMO, the biggest thing is the lack of cross lateral cross brace'n...
I know some guys can't afford to lose, or choose not to lose the space, like in FatKids sammy... that is why it's made of 2"x .120... Insted of 1.5 or 1.75 x .120.. It's a give and take..

Good mounts are another thing....
Go right to the frame if you can...
If not, make a DAMN good mount/standoff..
Kinda like "The house is only as good as the foundation"

And lastly, A little practice with the welder go's a LONG WAY......
take a bunch of scrap tube, and practice weld'n it up.. Most people can lay a damn good bead straight flat and level, but once out of position


It's not hard, just get use to welding vert and over head, until you get comfortable.

Take your time, there is no race to get it together, and you'll be ALOT happier with the end result... :A cage you can be proud of, and one that you KNOW will take a good hit...

PS!!!!!
KNOW WHEN TO STEP AWAY FROM THE BENDER!!!! Do you remember EB BRONCO
Sometimes, it's easy to get carry'd away...

[TNToy]

Yeah... I remember that jungle-gym Bronco. Hard to forget.

We need a "BoneHead 4x4 Discussion" forum for all the stuipd shitzu people do to build a rig.

Thanks for the reply. Good stuff... and I definitely understand DRM-Phobia.

[CragRat]

I would love to do an Exo cage on my tin top 86' but, How would you get good cross-bracing and still not penitrate the body, block the rear door or cross the windshield ?

Dave