Tubing questions

[Bonehead]

I had this question sent to me as a PM. But I could not send a PM back due to the persons settings, So here is my response.

hey man ,, i been think about something, maybe ya can help,, since you do build tubed frames,, i have a 48 ford cab,, i think i want to build a tube frame, kinda dragster looking,, want would you recommemd in useing for tubing,, i was think seemless pipe, cause i can get it ,, a freind works for a fire sprinkler placre , and always has plenty,, what size if possible should i use if i get the seemless pipe,, pros and cons,, thanks man,,

Don't build it out of pipe. Pipe is not made for structural applications. Sprinkler pipe is pretty thin walled usually too. You are better off to use an HREW tube,(hot rolled electrically welded) or a DOM. All in a 120 wall.
DOM would me the best, short of chromolly. DOM is seamless. I like 1 3/4 inch but 1 5/8 is good too. The price of steel is going down now.

 

[Hopsing]

Dont use pipe! That stuff will literally break under load. I've seen airbag mounts snap in half made of that stuff. Like Bonehead said, .120" wall minimum, DOM seamless tubing preferably. Its your life riding on that chassis, do it right the first time 'cause you may not get a second chance

 

[Gearhead10]

After all the racecar chassis that I've built I'd have to say that DOM .120 wall tubing would be the way to go.1 3/4 or 1 1/2 dia at min.If the guy would build it with angle braces between the upper and lower tubes and use gussets I'd say it be plenty safe. If he's got alot of $ and a TIG go with chrome moly tube.You can make a pretty ridgid and safe chassis with tubing if ya do it right.

 

[Rev Tex Devlle]

hey guys thanks for the help.. sorry bone head,, didnt know my settings where wack,, will check themm,,, tex

 

[Rev Tex Devlle]

i did some research on the issue of pipe thickness and dom thickness,, the pipe is .145 to .200.. its coldrold seamless.. isnt that thicker than the dom pipe? would the issue be rather brittle, the dom pipe being thinner walled would possible be more apt to bend, where the pipe would be more apt to break? i aint talking about building a really dragster,, no reall power,, really a 6cylinder 5 speed. schedule 40 is .145 schule 80 is .200

 

[Rev Tex Devlle]

well i found what i was looking for,, in the event of a accident black schedule 40 pipe will split, the demensions are a little stronger, and dom is the same pipe but drawn thru one more process,, to make it, more fexible,, therefor it is why it is used in racer cars and other applications,, due to its ablity to flex in a torsion manner.. tensil sterngth is lower in the DOM pipe but more flexible.., tada

 

[Bonehead]

Way to go. Usually it works like this though... You ask a question, then someone else answers it.

I guess it is okay, as long as you don't answer yourself in a another funny voice.

 

[Gearhead10]

Your right about schedule 40 pipe.Britle and will break before it'll bend. DOM wall thickness is more consistant than HREW.Most dom that is rated for .95 wall is usually .104 wall. HREW that is rated for .95 wall is usually .85, very inconsistant.That is why when we built racecar chassis we always built the cages out of DOM.Placement of support tubes in the chassis will greatly help make it more ridged and less flex.

 

[bob w]

When building roll bars and cages for drag racing in the NHRA they make no distinction on HREW or DOM, when using mild steel. The spec is .118" wall. Many builders, recognizing the inconsistency of HREW wall thickness use .133" wall to avoid any problems with Tech. sonic testing. The two 14 point cages I bought from Chris Alston Chassiworks were HREW, .133" wall. I would think that HREW in a sufficient diameter and wall thickness and braced and gusseted properly would be quite satisfactory for your project.

I just checked prices locally. A 20 foot stick of 11ga. 1 1/2" dia. HREW is $47.76 and the same in 1/8" wall DOM is $98.78.