Suicide front suspension materials, strong enough??

Does anyone know where I might get some appropriate materials? I know there have been a few sites posted, but I am from Canada and we get raped with shipping and duty (usually the price doubles by the time it gets here from the US). Any Canadian suppliers around? My local one where I got my frame material doesn't have tubing.

 

Try your local steel supply, they may even sell you a piece of drop cheap.

 

We will agree to disagree.

 

Check with Paul Horton Welder Series, http://www.welderseries.com/hardcopy/weldercat.pdf

If he doesn't have it he probably can tell you a local source.

 

Here is a link to steel suppliers in Saskatchewan. I don't know where in saskatchewan that you are but you could actually narrow down the search yourself.

Now let you fingers do the walking. Start calling around. You are not looking for unobtanium.


http://www.google.com/#sclient=psy-...gc.r_pw.&fp=3c3de782628f59c5&biw=1024&bih=547

 

Hello
about materials discussion. I t is not only what material are you using, it is more about dimensioning of the members you are using in your structure.
It means strong material less diameter or thickness. The way forces are acting is another issue.

But In structures the worst part use to be the welded unions. As a mater of fact, maybe worst if you weld a allied member with structural steel on the chassis, that's because of structural changes in the materials on the welded union.

Anyway is not a matter of who has the big one is how you use yours.

Analysis and calculation is the best recipe.

 

Pretty easy to calc the dead load on the front of a chassis but I would think that comming up with moment and or live loads would be a little more involved. You would have to calc the g forces for any given situation as well as driven force from one moment to the next.

 

Ok so I got the guy who I could get the pipe from to pull the inspection sheet for the batch, I was curious of the specs since the stuff is tested at 3000 psi pressure. The structural DOM tube from the site you guys gave is as follows:
Brinell - 80; Tensile - 80,000+/-; Yield - 70,000+/-;

The pipe (same wall thickness & diameter, tests are for the batch) I can get was actually tested to have the following:
Brinell ~130 (HV10 hardness test converted to brinell by yours truely);
Tensile ~ 520 mpa (so 75,400 psi converted)
Yield ~ 350 mpa (so round 52,200 psi)

Any thoughts?

Thanks guys! Thus far this thread has been very informative

 

Use what you want you already have our suggestions.

 

Are you planning to MIG weld the tube to the frame and MIG weld the perch to the tube? If so, you are probably better off with the plain steel pipe. If you are planning to TIG weld it, then the DOM tube is probably the better option. From what I understand, DOM tubing should not be welded with the MIG method. The pro welders should chime in on this though.

 

The DOM that most of us use is just mild steel and can be welded with tig or mig. Most dragster chassis are tig welded.

DOM is nice to say when you are selling one but as I have suggested more than once just standard mechanical tubing is going to be fine for this application and costs less. The big difference when you look at the two is that mechanical tubing has the weld bead visible on the inside.

On a side note I would not want to say that my suicide mount is attached to gas pipe when I was selling a car and I would feel compelled to be honest.

 

Well, there really is no such thing as "gas pipe". It's ASTM A53 carbon steel continuously welded pipe.

 

This is making me crazy. Pipe is a rated steel material just like any other product. Calling it "water or gas pipe" implies that it is an inferior material. Jkeckss I admire your diligence in wanting to build a safe car. That is good for you and everybody else on the road. We build structural assemblies every day and we use various tube products as specified by an engineer. This forum has supplied lots of opinions and I can see how you might be confused. At this point I would recomend that you sit down with a structural engineer who can explain exactly what will happen when you stick all of these pieces together. The strength of the pipe is not the only factor here. Best of luck.

 

Just to add to the fun
I shortened a drive shaft for a buddy the other mouth. I was very surprised
how thin and that there was a welded seam.
2 3/4 .076 wall

 

You must learn to speak to your audience, you are not speaking to a PE or a man that has had several years as a structural fabricator. He can understand water pipe or gas pipe when he will not understand ASTM ratings.

I have been involved in structural design for quite awhile, I cannot understand where you would find a PE that would even suggest using a conduit in place of structural iron. Less in a situation where there is going to be constant twisting and flexing not to mention ever changing moment loads like an automobile chassis.

Maybe there is an easier way to explain it, there is a reason why most if not all race sanctioning bodies will not accept a fluid transfer conduit as a load bearing part of a chassis. While one cannot call this type of material inferior in its intended environment it is not intended to take the stress of an automotive chassis.

I don't know that I could take the liability of suggesting that someone use a piece if iron of unknown origin to build an important piece of his suspension. He called it pipe, it was suggested that a piece of pipe intended to use for water or gas is not a good piece to use for his suicide mount.

I respect the fact that you own a fabrication shop but you are not giving the young man sound advice.

 

Just use an old driveshaft, they are strong and thick, ive done it before. i belive old chevelle is like .187 wall or sumthing, but it's been a long time

 

I don't know when conduit came into the conversion but in my last post I suggested that the OP discuss his project with a design professional so that he can understand all the forces that your suggesting. When I lived in San Diego I built off road frames. Sanctioning bodies specify materials so that ametures and professional racers can build a safe frame without having to have each one indivudially engineered. My guess is that the OP has specs for various materials and assumes the a bigger number is better. I understand my audience and I refuse to dumb down the conversion. This is how people learn and compare information. I believe my advice is as sound as yours.
As I said we will agree to dissagree. Unfortunatly the OP and others are dazed and confussed. At some point an informed decision will have to be made. I'll miss our talks.

 

You're quite correct. 30+ yrs. as a weldor/fabricator I've built many structures using pipe and these were all spec'd by engineers.

The first thing that needs to be understood is that the primary difference between pipe and tubing is sizing. For example: A "2 inch" pipe will not measure 2 inches in any way and the wall thickness will be determined by its "schedule" (40-80) nothing more or less. "2" tubing, on the other hand, will measure 2" o.d. and can have a variety wall thickness's from .0xx to .xxx. So comparing pipe to tube is kinda like comparing apples to oranges. Having said that, and for the sake of argument, a piece of pipe formed and welded in the same manner out of the same grade of steel as a piece of tubing in a near size will have a essentially the same strength. Example: a 2 inch (actual 1.900 o.d) pipe with a schedule 40 wall thickness (.145) and made from, let's say, grade 1018 or comparable steel will have a stength comparable to 2" (2.00 o.d.) .120 wall tubing. The fact that the pipe may be intended to transfer water, gas or whatever, has nothing to do with its strength. Like I said before, steel is rather dumb. It doesn't just give up and get weaker because it's going to become pipe.

Also I keep seeing reference to racing specs. I don't think the OP is intending to build a race car. If race car specs are our benchmark then consider that USAC requires 4130 cond. N tubing and nothing less. So I guess that means nothing else is suitable for any wheeled vehicle ? ??

 

Conduit is what a water or gas line is called, any line or tube or even a culvert for that matter that transfers a substance from point A to point B is called a conduit, even a tunnel can be and often is refered to as a conduit, I was using it in place or gas line or water line or pipe. See I didn't dumb my conversation down and speaking with one who would know and still didn't get the point across.

He is just starting out and really needs to be working with mild steel, but he still needs to be working with a steel type that has a tight enough grain as to not easily tear. The one thing that we don't want to happen is for one of these fellas to think that it is OK to go to the plumbing dept at lowes and get a piece of pipe to build their suspension on.

 

I think this whole topic is tainted by common mislabeling...as it has been forever.
Some people see a seam and think its no good...others see the word "pipe" and the first thing pops to mind is CAST sewer pipe!

Confusion runs rampant!!!

The worst part of it all is...even the CONFUSED are 100% SURE they are passing on proper info!

What we need is a properly certified STRUCTURAL ENGINEER to explain (in simple terms) what is and what isn't acceptable...because all this MISINFORMATION just expands and makes matters worse.

(Now...I'm not saying the proper answers haven't been given...just that things haven't been explained in such a way that the cloud of confusion dissipates!)

 

To me, the term "conduit" refers to a hollow electrical raceway used to carry wire. It's thin-walled tubing, not meant to be used in a structural capacity.

 

Designers for lack of a better term use the word in reference to anything that conducts any material. I used a term that one would see on a professionally prepared blue print because someone said that there is not such thing as water pipe.

Someone said that we should not dumb down a conversation down to meet our audience so I didn't.

One simple truth, never speak above the understanding of your audience. You will only loose your audience.

 

I give up.

 

http://www.cecalc.com/SteelShapes/RoundSectionProperties.aspx

Have fun guys

 

Now you just took all the challenge out of it.

 

I'm a Professional Engineer (PE). Feel free to dumb down the conversation though, I'll try to keep up.

 

Justin,

Go to the opening post of this thread----> http://www.jalopyjournal.com/forum/showthread.php?t=702443 if you need ideas on how to set up a round crossmember for a suicide setup. I like how he attached the crossmember to the frame rails......it's set up to offset the moment forces imposed by the cantilevered perch mount of the spring. Neat, clean, effective.

 

If you get too 'mechanically correct', it won't be 'suicide'! It'll just be (yawn) safe.

 

Thanks VoodooTwin for the note of confidence. Just so everybody knows, that setup is based on Norms front end on the "Lightning Bug", the predecessor to the "Kookie Car" everybody knows. That one is built with 2 5/8" .250 wall welded tubing.

By the way, I'm a CRD so my engineering backround is architectural but involves a fair amount of steel calculations. I hold to my earlier statement about "pipe". We commonly use schedule 40 in compression, (columns), but seldom in a live torsional application.

'Nuff said!

 

Nice work, Koz. You got mad skills.