Square Tubing Wall Thickness?

[drunkonhighseas]

I got my BSR plans and started collecting my parts. I bought 40 feet of 1" square tubing. My question is... Deos it matter all that much if the wall thickness of the tubing is not 1/8" ? I have began construction of my frame, and it's going together better than I thought, but will it hold together if the walls are a little thinner than 1/8" ??? Any suggestions?

[Mike Bean]

Honestly I am not an engineer, but I would recommend using the 11 guage (.120 wall) just to be safe.

I know I put a good beating on my BSR from time to time and I know it will hold together.

Why are you thinking of going to a thinner wall? On my last purchase of 1" X 1" X 1/8", I paid $1.30 per foot. The price has been holding stable for the last few months unlike other steel prices.

What is the wall thickness of the material you are curently using?

-Mike Bean

I got my BSR plans and started collecting my parts. I bought 40 feet of 1" square tubing. My question is... Deos it matter all that much if the wall thickness of the tubing is not 1/8" ? I have began construction of my frame, and it's going together better than I thought, but will it hold together if the walls are a little thinner than 1/8" ??? Any suggestions?

[D&Jracing]

.065 will work just fine or .083... .065 is thick than that used on the fron of cup car bumpers.

[elvergon]

well i know that square tubing has more strength than circular tubing but let me tell you my experience. I started doubting about using 7/8 .125 wall tubing....I went on....did A LOT of work....and welding, and finally when I was starting to care about where to put the stool and I got myself on the chassis I made, I realized that the chassis would flex( I dont kno if forever but when I moved and I was over the chassis it would flex). I would recommend you not to go with 7/8 .125 circular tubing so I will probably suggest that you do some nice welds and probably test it and ask for someone which knows more. It isnt a game, its your life.

[Mike Bean]

Elvergon,

Are you still going to finish your bar stool racer or is it going to the scrap yard? You sounded like your done.

Mike
well i know that square tubing has more strength than circular tubing but let me tell you my experience. I started doubting about using 7/8 .125 wall tubing....I went on....did A LOT of work....and welding, and finally when I was starting to care about where to put the stool and I got myself on the chassis I made, I realized that the chassis would flex( I dont kno if forever but when I moved and I was over the chassis it would flex). I would recommend you not to go with 7/8 .125 circular tubing so I will probably suggest that you do some nice welds and probably test it and ask for someone which knows more. It isnt a game, its your life.

[elvergon]

no bro, im done with it, the tube is very flexible and i was done with the chassis. I think that instead of buying more tube and reinforcing what i have it might be better to buy square tubing and start another one. Also the axle i had was very flexible. Maybe if i can get some money i could probably try to finish it and hope that it doesnt flex but i dont think that its posssible...Since I also had trouble with the hubs because i messes the striated i will need to make my own hubs. But now i have access to a lathe and a mill and learned how to use them. So ill start by making the hubs. Anyway thanks for asking...btww i bought an Lilcoln electric 225 ac arc welder, and im spending money in the conection for it. I hope that i can be again in the building process in some weeks. Also i learned TIGing, i already knew how to MIG. I been busy because some friends and myself are finish a MINI baja, which is from Society of Automotive Engineers and the race is next week so we are spending all our effort on it.

[sniffles]

hi im wondering, is 2.50 expensive for 1"X1"X1/8" tubing? these guys are pretty much the only tube suppliers in washington state.... :smash: i might have to hit someone with a hamer

[royster]

well here in va i paid 1.22 a foot for mine

[sniffles]

hey thanks, i just found a place with mild steel for a good price...cash only..nice. it will be about 55 dollars for 40' of mild steel.

[tk20fan]

I called one of the local steel suppliers and they wanted $2.40 a foot, so I called a fab shop a couple miles away and he sold it to me for a $1 a foot!!!

[stool-sample]

I would try your local welding shops. Theres got to be one somewhere. They will buy bulk which is cheaper, but they will add some to the price just for shipping. Glenn

[Mike Bean]

We get our steel for $1.30 per foot here and we get FREE cuts.

MIke
hi im wondering, is 2.50 expensive for 1"X1"X1/8" tubing? these guys are pretty much the only tube suppliers in washington state.... :smash: i might have to hit someone with a hamer

[RUBICON]

Hey guys....10' should be enough to build a standard frame...plus whatever other steel is needed for the steering shaft brace. The thickness desired depends mostly on one thing...your ability to weld....think about the flex that others have mentioned...this thing is less than 30" long between axles...with a stool bolted to the top...think about the forces....the are close to the axles....1/8" is great for even the beginning welder...but if you have thinner the joints have to be good. I prefer the 1/8" because it is more mass and I can tig and grind smooth and still have a good joint......good luck

[Prowrench22]

Actually most steel supply houses stock 11, 14, 16 gauge 1" x 1" my guy charges $1.00 a foot when you buy a 24' piece we bought 4 sticks, shop around guys. :wave:

[moto1fast]

Hello, I called around here in East Texas and found the cheapest here is 1.25 foot! :wave:

[Prowrench22]

Well I guess that makes sense I live 60 miles from where US Steel is located.

[bm1]

My shop is close to a recycler that buys from a lot of big companys that scrap out a lot of material. He buys a lot of aluminum sheet from a trailer mfg., I mean skids and skids of this stuff. The only thing wrong with it when they stack the sheets at the mill, they put a piece of paper between them. If the paper gets wet, it will discolor the aluminum a bit and they scrap it. A piece of scotch-brite and it comes right off. Same with tubing. I buy a lot of 1" stuff that is new, but maybe one end has a little rust on it, or has a few dings in it. I buy it buy the pound and I use a lot of it. Look around some of the recyclers in your area, you might be surprised. Steel is so outrageous now, it pays to shop. China is buying everything we got so we have to buy raw steel which is more expensive. Then China ships it back to us in a finished product and we buy it. What a pisser!

[D&Jracing]

11ga .69 and 16ga .59 a foot in nc for a 20 foot stick

[bradw1]

does it matter if it square or round tubing. i have access to pipe bender and like thelook better. just getting ideas before i get started. thanks brad

[bm1]

Tubing and pipe are measured different. Tubing is measured outside, and pipe is measured inside, therefore, the dies used to bend them are different. A lot of time when you use pipe dies to bend tubing, it will kink or flatten out in the radius of the bend making for a crappy loking bend.
Another thing to think about is square verses round. It might not make much difference on the stools we are building, but square tubing only flexes in two directions, up and down. Round has torsional flex which makes for better chassis handling, but like I said, on these short wheelbase chassises we are building, it might not make much difference. But then again, it depends on the chassis design, narrow or wide. Oh Oh, I'm rambling again............

[bradw1]

Tubing and pipe are measured different. Tubing is measured outside, and pipe is measured inside, therefore, the dies used to bend them are different. A lot of time when you use pipe dies to bend tubing, it will kiotnk or flatten out in the radius of the bend making for a crappy loking bend.
Another thing to think about is square verses round. It might not make much difference on the stools we are building, but square tubing only flexes in two directions, up and down. Round has torsional flex which makes for better chassis handling, but like I said, on these short wheelbase chassises we are building, it might not make much difference. But then again, it depends on the chassis design, narrow or wide. Oh Oh, I'm rambling again............

i would be using pipe not tubing.
i understand the difference. if i used 1 1/4 pipe such as the pipe used for karts just not chrome moly. would that be ok or is square tubing better. just looking for opinions as i am new to the bsr's

it will be the short wheelbase but i might make it a little wider. not looking for racing just riding around the pits and at parades. i have access to a professional pipe bender not a problem on good looking bends. thanks brad

[Mike Bean]

Bradw1,

One thing to consider when chosing what to use it, can you weld? and can you weld round tubing?

I can weld, but still learning the round stuff because it is a bit more difficult to follow (at least for me it is)...

Mike


does it matter if it square or round tubing. i have access to pipe bender and like thelook better. just getting ideas before i get started. thanks brad

[bm1]

1 1/4 pipe would be pretty big and would take away from the looks I would think. If you are going to use pipe, I would use 1" material. If you are just going to putt, square tube would be fine. Unless you have access to a bender that will bend square tube, you are limited to square angles. I would go with the pipe. I am bending up a square tube chassis now in the shop. I have a die that will make radius bends in square tube. I bent up a mini chopper out of square and it looked pretty cool. I've just always been a fan of round when building chassis. It's just a matter of preferance, which do you like best.

[bm1]

Mike,

Welding round tubing is not all that hard to do depending on what type of machine you are using. If you're using a TIG and are fairly decent at TIG welding, you shouldn't have any problem. The biggest thing about getting good welds is being comfortable and having good access to the part you are welding. Some times in order to get a weld all around a tube, you might have to move your piece several times. When stopping and starting on your weld pass, always try to start right where you left off. Try not to overlap the weld because you will leave a thick weld on that spot and it will look bad. Just butt right up to it and take off. Another thing that is very important is that you should be able to see the area very well.( Read my post about the magnifier lens ie. strong reading glasses work great and they are cheap) MIG welding causes some spatter and you will have a lot of cleanup to do if you don't use some sort of anti-spatter. Welding supply stores sell it in gel or spray. CHEAP TIP: Have a small container of ATF and dip your nozzle in it every so often. This is a great anti spatter.
Another method of MIG welding is what some call the "stitch" method. It's like tack welding all around the tube. If done properly, you can get a nice looking strong weld that looks like it was TIG'd. A lot of chassis builders use this method because you are not flooding the area with a lot of heat causing distorsion. With some practice getting your weld "tacks" even you will have a nice looking weld. Just like anything else to become proficient, it takes practice.
Wire diameter makes a differance also in the welds. I prefer smaller diameter wire for my Miller 200. Usually .025. You can get some nice clean welds with the smaller diameter. Kick up the heat just a bit and the wire flows in like butter. Don't forget, when you kick up the heat a little, pick up the wire speed just a tad. You may have to play with the speed some to get it just right as not to get a lot of "popping" and sticking. Hope this is of some help. I'm not an expert, but I have been in business for 25 years as a fabricator, and even I learn new stuff everyday. EXPERIMENT....you'll have fun.

[Mike Bean]

BM1,

Thanks for the tips! Much appreciated!

Let me ask you, on .120 wall mild steel, would you recommend .030 or .025 wire for the tack welding method with MIG?

I was never aware people actually did tacks for complete welds. I have hear dit once before but never believed it. I think that would help a lot because installing a roll cage does not give a lot of room to work and MIG welding is pretty quick and it can be easy to screw up on round tubing.

Someone else told me to make tiny circles. I have tried that but still have problems keeping the tip placment correct when moving around the tubing.

Mike

[bm1]

The trouble with the "making small circles" method is that most MIG guns are a bit cumbersome anyway, and unless you get the same amount of penetration on each piece of material, you will have a faulty weld. I've seen some welds that look good, but could actually break the piece off with my hands. It would have penetration on one piece and not the other. On the .120 wall, I would use the bigger wire diameter(.032) especially if you are talking roll cage material for a big car. The smaller diameter stuff I would use the smaller diameter wire to get a better looking weld and not be so "bulked up". I think if you practice the "tack" method, you get some nice looking strong welds. Remember, when welding tubing together with closed ends, you should always drill a vent hole(1/16") in the tubing to let out the hot gases inside the tube. If you don't do this, you will have a hard time finishing the weld because the hot gasses will need a place to escape and it will blow a hole in the end of the weld. After you get everything welded up, and after it cools, you can go back and spot the vent holes and file them smooth and you won't know they were there.

[Guy]

http://www.studmonkeyracing.com/v2/barstool/barstool3/DSC00301.JPG

I think TIG (Tungsten Inert Gas) can give pretty well finished welds, but is more expensive, and more of an art.You hold both a gun like mig, blus the rod, like brazing.
Just about anyone can get a cheap MIG (metal inert gas) even flux-core, and weld solid welds with some practice.
Studmonkey has done really well with square tubing on his, I think, He's using square tube, and even got a nice looking bend on the front.
Anyone building their first stool should make sure the welds are sound, the angles are correct, the axles are straight, Safety first, function before form, and I think you can make a square tube BSR look nice, just look at Bean's..

[Guy]

11ga .69 and 16ga .59 a foot in nc for a 20 foot stick
Just paid $39.14 for 20ft 1x1 .120 square tube in Anchorage, Alaska

[scooterpimp]

Just Remember There Are Different Grades Of Tube Not All 1"x"1 X 1/8 Square Tube Are The Same. Cold Rolled , Hot Rolled. Extruded Etc. F.Y.I. Da Pimp.:smash:

[elvergon]

BM1,



Let me ask you, on .120 wall mild steel, would you recommend .030 or .025 wire for the tack welding method with MIG?


Mike


Hey Mike..."tack welding method" does not work at all, you will only make a pretty bad weld which looks cool. Everytime you tack and tack, you´re starting a cold weld, which isn´t safe. You should run a "non stop weld"...well at least not tacks....2 welds (180 degrees) on round tube is acceptable, 3 is on the OK limit...

Please tell me you didn´t tack weld your cage...

I was told this by a lot of people that weld for a living and also chassis building (1/4 mile) guys. It is a very bad error thinking it is OK to "tack weld"...

Just worried for you bro

[elvergon]

Mike,

Welding round tubing is not all that hard to do depending on what type of machine you are using. If you're using a TIG and are fairly decent at TIG welding, you shouldn't have any problem. The biggest thing about getting good welds is being comfortable and having good access to the part you are welding. Some times in order to get a weld all around a tube, you might have to move your piece several times. When stopping and starting on your weld pass, always try to start right where you left off. Try not to overlap the weld because you will leave a thick weld on that spot and it will look bad. Just butt right up to it and take off. Another thing that is very important is that you should be able to see the area very well.( Read my post about the magnifier lens ie. strong reading glasses work great and they are cheap) MIG welding causes some spatter and you will have a lot of cleanup to do if you don't use some sort of anti-spatter. Welding supply stores sell it in gel or spray. CHEAP TIP: Have a small container of ATF and dip your nozzle in it every so often. This is a great anti spatter.
Another method of MIG welding is what some call the "stitch" method. It's like tack welding all around the tube. If done properly, you can get a nice looking strong weld that looks like it was TIG'd. A lot of chassis builders use this method because you are not flooding the area with a lot of heat causing distorsion. With some practice getting your weld "tacks" even you will have a nice looking weld. Just like anything else to become proficient, it takes practice.
Wire diameter makes a differance also in the welds. I prefer smaller diameter wire for my Miller 200. Usually .025. You can get some nice clean welds with the smaller diameter. Kick up the heat just a bit and the wire flows in like butter. Don't forget, when you kick up the heat a little, pick up the wire speed just a tad. You may have to play with the speed some to get it just right as not to get a lot of "popping" and sticking. Hope this is of some help. I'm not an expert, but I have been in business for 25 years as a fabricator, and even I learn new stuff everyday. EXPERIMENT....you'll have fun.


BM1,.... As far as I have read....stich welding is more like a "BIG weaving" motion used in TIG....after you´ve done the "hot or root pass" (usually without fuse) and then a "filler pass" or just "root and filler pass". Usually done on very thick steels or when high pressure is involved. Here´s a pic of what stich welding looks like, It isn´t any form of tack welding.

Now if I try to think of stich welding for MIG, I would only think of a big weaving motion...

Am I wrong? Where did you get that info?

(pic Fuse pass)

[elvergon]

(pic : filler pass)

[elvergon]

(pic: stich pass)

[Nitefall]

I Just Called Our Local Steel City Rep And He Quoted Me $1.00 Per Foot, In 20' Lengths.
Nitefall

[Mike Bean]

Hey Elvergon,

Don't worry..No tack welding here. I have decided to work on learning TIG for round tubing.

Also I always do destructive testing on new welding techniques and types of welds that I am working on with my 20 ton press. :smash:

Thanks for your concern!

Mike

[moto1fast]

Hmmmm! Let me guess!! Wire Rope spool for Winch or tugger! Nice welding by the way!! Looks almost mechanical, Robotic welding!! LOL

[elvergon]

Lol...those are not my welds but I can get em to look almost as nice...still practicing....

it´s easy to weld in round tube....well...I learn a technique in monster garage...Just put on a nice glove on your left hand...Now lay the gas nozzle of the gun in your fingers...supporting it nicely....Now you got an awesome contorl on the gun....Just remember your hand is next to the joint you´ll feel the glove turning hot fast ;)

[KiwiMike]

Getting back towards the core subject of this post.
Round tube versus Square tube.
Due to the speeds we attain on these things, tubing shape is a personal preference based on skills, tools, time and aesthetics, but round tube takes a whole lot more work to fabricate.
Flex in a frame can be both advantageous and disadvantageous.
Obviously if you can feel or see the flex, then you should probably keep your backside off it.
However most kart frames are computer designed with flex built into the frame, which promotes, steering, corner speed, extra traction under braking and acceleration.
Due to running a live axle, this frame flex and tire pressure is the only suspension you will have.
Most karts have round 1-1/4" (32mm) longitudinal chassis tubes with round 1" (25mm) lateral tubes.
Once again I apologize to the experienced builders, this post is aimed more at the newer builders.

[saf]

Im yet to make my first BSR, but i build cages, and chassis components all the time. If your going to tig weld, what is the best way no question, and your doing round tube there are a couple things that will have a huge effect on how it goes, and how long it lasts.

Buy a notcher. The gap between the joint has to be as close to nil as possible. You can buy cheap ones on ebay, and you can buy pro ones still on ebay from tricktools.

Preheat. If your not a welder by day, preheating is going to get you going into a better weld. A small bernzomatic isnt expensive and will warm the joint so you can get a good weld going.

And if its for a CR-MO BSR frame, you will love to use 312s/s (missile weld as its sometimes called) . Works like a charm. For the little amount of steel in a BSR, ill be going CR-MO.

[saf]

(damn quick reply didnt reply so well, take 2)

While im yet to build my first BSR, but a word of info for people wanting to use round tube.

Notch. Buy a notcher, cheap one on ebay, or up to a pro series on ebay from tricktools

JD2 Notchmaster
Link Here (http://cgi.ebay.com/JD-Notchmaster-JD2-Notch-Master-Tube-and-Pipe-Notcher-/120702944373?pt=LH_DefaultDomain_0&hash=item1c1a74c475)

The gap between your tube needs to be as close to NIL as possible. Use a grinder and expect the weld to fill it, your 3/4 way to a failure already.

Preheat. Unless you TIG weld by day, if its a part time thing for you, a little bernzomatic propane unit will preheat the weld area, making your job much easier.

And if you want to go 4130 CR-MO (for the amount of steel these take, ill be going 4130) try 312s/s. The results and durability is amazing.

[saf]

Getting back towards the core subject of this post.
Round tube versus Square tube.
Due to the speeds we attain on these things, tubing shape is a personal preference based on skills, tools, time and aesthetics, but round tube takes a whole lot more work to fabricate.

Bingo. Having said that, if your using round tube, and your flexing to the point its making you sea-sick .. your doing something wrong.

Round tube is used in karts, roll cages, tube frame chassis circuit and drag cars ... not square, and for a reason. Square is much easier to work with if your not a fabricator.

Ill be going the round tube method, in 4130 CR-MO. I can probably build the whole chassis from offcut here, but even if not it is still a great product to use. As Mike says tho, round frames are a pain to worth with, notching and lining up can be a pain.

[MEATHEAD]

This may be a dumb question but which type of square tubing will be stonger? Hot Rolled or Cold Rolled or does it even matter which one I buy.

[KiwiMike]

It isn't a dumb question at all. The differences are in the steel making process, with hot rolled steel being rolled to it's final dimensions while hot enough to build scale (over 1700 degrees F). Cold rolled steel is rolled to final dimensions under this temperature.
The tolerances on cold rolled steel is a lot smaller than hot rolled steel, therefore cold rolled steel is better to work with if you can afford to pay the extra cost.
Also the squareness of the cold rolled steel product is a lot better than hot rolled steel, although cold rolled steel is harder to machine as it is work hardened in the rolling process.