mild steel tubing

[clyffcarlock]

I read that bike builders are talking about "mild steel tubing" which I also read is different from muffler tubing.

What is the difference?

Where can i acquire raw unfinished tubing and when I call a supplier what should i ask for aka "in what metal tubing lingo will they understand what I am talking about"?

What dimensions as far as ID, OD, wall thickness should I tell them, by that I mean what measuring standards should this be in? (inches, mm, fractional inches) ex. "inches-1.0345, mm-25mm, fractional inches-2 1/2""

Note: these are examples and not sizes that I want.

One last thing, which is better, muffler tubing or this "mild steel tubing"?

Thank you.

[trikeman]

clyf - I think most exhaust tubing is mild steel, but some has been aluminized or even powder coated. Some is also thicker than the common 16ga tube most of us here use. Coating it doesn't make it stronger, it just keeps it from rusting. Some exhaust tubing is also thicker than 16ga, but you can also get plain uncoated steel in most any thickness you want. Thicker is heavier and stronger. There is also exhaust tubing made from stainless steel, but I don't think that is what you asking about. I think some people use exhaust tubing because it is commonly available in large diameters with thinner walls (16ga for example) than your steel supplier may carry.

http://www.prostreetonline.com/s/fabrication_exhaust-piping.asp

As far as your supplier, the big supplier I deal with carries mostly mild steel. They can get other stuff, and are very helpful if you just talk to them on the phone. If you want mild steel just ask for it. Some bike builders use 4130 or "chromoly" steel because it is stronger, so you can use thinner (and lighter) tubes. Most of us here don't use much chromo because it is more expensive and you have to a bit more careful about heat treating it after welding. Most people buy chromo from aircraft suppliers such as AircraftSpruce.

One of the things I like about my supplier is their online presence. Even if you don't want to buy from them you can use their web pages to see what sizes and types of tubing are available here:

http://www.imsgasteel.com/products/steel/index.html
Hope that helps.

BTW - good old EMT available from Home Depot is mild steel, and has been very good quality steel since the standards for it were changed some years ago. It is of course galvanized, which can make it a pain to weld and deal with, but I have used a lot of it as have others here.

[clyffcarlock]

I work at a concrete plant driving the trucks.

We have access to hydrochloric acid aka "muratic acid" we use to clean the trucks and remove concrete, which I have read can easily remove the zinc "galvanized" coating on the emt conduit, instead of sanding or welding it and giving off harmful fumes.

Not to say the acid fumes are anyless harmful, but with the proper face mask, cartridge filter and ventilation it should be safe.

Please correct me if I am wrong on the acid removal process, have not tried it yet.

The size conduit you are referring to is around 1/2-3/4 inch size to use for the seating. am I correct?

Is there any other size emt conduit that is larger that can be used for the frame or crossmember/axle portion?

Is the emt conduit lighter than the muffler tubing or the "mild steel tubing"?

Is there any other special benefits in using the gal. emt conduit?

Thanks again.

[Sparky]

i bought my steel from metalsdepot.com. i honestly dont know if their prices are high or low, but they were the only place i knew to look back when i built my streetfighter.

my chopper was built from 1" EMT from home depot. it worked, but i would kina be nervous to use it as a main structural support- it was REALLY thin walled and easy to bend.

[trikeman]

clyff wrote:

The size conduit you are referring to is around 1/2-3/4 inch size to use for the seating. am I correct?

My Home Depot carries EMT in sizes from 1/2" to 2". I used 1/2" for the last seat I made.

Is there any other size emt conduit that is larger that can be used for the frame or crossmember/axle portion?

See above.

Is the emt conduit lighter than the muffler tubing or the "mild steel tubing"?

It depends on the thickness. If you get the same diameter and thickness, it is pretty much the same weight. There are some wierd sizes on EMT, in that it is measured by inside diameter, not outside.

Is there any other special benefits in using the gal. emt conduit?

Not really. Its main advantage (as far as I can see is I can get it after business hours at Home Depot and its pretty cheap.

[Sparky]

as i recall, the emt i got was measured in mm. it was "about" 1 inch, but i think it was exactly 30 mm or something like that.

x2 on the after hours at home depot.

[clyffcarlock]

Thanks everyone for all the info.

One last question and that should be it for today... or for the next few minutes:D

I was also thinking about using the same dimension pipe (other than the 2 1/2 pipe for the main support tube, and the 2" for my crossmember) that is used on normal Walmart style bottom brackets (If anyone knows this please help me out on this one. ID,OD, Wall Thickness, very big Thanks for this one) and cut the pipe to length and weld it to the end of my main support.

Does this pipe need to be threaded to accept a bottom bracket cartridge aka (crank) or can I use some bearing cups pressed onto the pipe?

Would like to have a 3 piece crank.

Hope this all makes sense.

Would like to construct a bike with all tubing purchased new from a (Lowes, Home Depot, muffler shop type store), just so, instead of looking for used bikes, if I need to build a frame fast I know where to get my supplies.

Is there any alternative method of constructing a bottom bracket that can be used instead of finding a old bike and cutting the bottom bracket off?

Sorry, I noticed there are two questions, albeit they are some what related. So it is like one question expanded.:eek:

Sorry, I just love that :eek: face. wish I could get that blown up and put on a t-shirt.

Thanks again guys.

[Sparky]

yes, most BBs are threaded to accept the inner parts. though i have seen an interesting "cartridge" type design on cheaper bikes. it was weird though- i dont know if i would reccomend it (non-standard parts = bad)

you can buy a new BB from online stores (and i guess local bike shops). some folks on here have gone that route.

why not cut a BB out of a donor bike?

[clyffcarlock]

You can buy the bottom bracket housing online?

What websites would sell just the housing unit, as far as just the threaded shell?

Thank you.

[PeterT]

I know Greenspeed sell just a BB but you would have to find a USA dealer or find their site to order online

http://www.greenspeed.com.au

PeterT

[trikeman]

http://www.cycle-frames.com/bicycle-frame-tubing/STEEL-LUGLESS-SHELLS/

[John Lewis]

I've built two SWB bikes and a tadpole trike from muffler tube. It works fine. My reason for using it was that it was still in inch sizes whereas the normal mild steel tube we get is metric and I couldn't get the sizes I wanted. I found the square tube was fine too.
It is good stuff to use and pretty forgiving for amateurs but you pay a bit of a weight penalty. It's also cheaper and that's important to me.

John Lewis

[fultondp]

Here's 3 other sources for BB shells.

http://forum.atomiczombie.com/showthread.php?p=30110#post30110

Darren