Cold rolled iron

I've just build [brazed amd MIG] a recumbent bike from old scrap
frames etc. It's my first attempt at any kind of brazing/welding. So
far everything is holding up fine.
I'm planning another one which will also use the tubing from old
frames as well as incorporating some brand new tubing. My local 'big'
hardware store has quite a good selection of metal tubing, but both
the round and the square tubing that I want to use[about 14mm x 1mm or
16mm x 1mm] comes under the heading of 'cold rolled iron'. My
knowledge of metal is pretty limited, but am I correct in thinking
that this is going to be weaker/softer than ordinary mild steel, and
so I should therefore refrain from using it? Or is 'cold rolled iron'
another name for mild steel?
I know only that steel, in all it's various varieties, is derived from
iron and various types are used in bike frame construction, and I also
know that strength is as much the result of design and geometry.
Weight is not an issue, I just want to make sure this stuff is going
to be ok.
Any input appreciated.
Thanks
Garry
Reply to
garryb59
Loading thread data ...
The material has to be labelled by an incompetant. You cannot roll or forge iron into thin sections. Cold roll indicates that there is no oxide scale on the surface. Likely you are looking at standard mechanical tubing that has a cold roll finish. It will be very suitable for your application. If you overlaod the material it will bend or twist before complete failure giving you fair warning. Randy
Reply to
Randy Zimmerman
The material you are looking at is more than likely cold rolled STEEL tube. It is made from cold rolled sheet steel (same stuff as in automobile body panels) that is rolled up and welded on an automated weld line. The cold rolling makes for a certain amount of grain refinement and is slightly stronger than equivilent hot rolled stock.
For a bike frame I'd like to point you off to a DOM (Drawn Over Mandrel) tube. It usually comes in a slightly higher carbon content plus the drawing process makes the tube more uniform and stronger than the cold rolled tube. More money of course but you aren't using a lot of material. And since the stuff from the local big box seems to be mislabled, who knows what you are getting there.
garryb59 wrote:
Reply to
RoyJ
garryb59 wrote in news: snipped-for-privacy@4ax.com:
As a recumbent rider myself with building dreams (That was my excuse for buying a migwelder in the first place) a picture of your creation would be nice Henning
Reply to
henning wright
Sure..although the image quality is rather poor.
formatting link
As you can see, the seat is a rather temporary affair[two bits of ply joined with a couple of door hindges paded with some basic foam] but it's surprisingly OK for now. If anything it's a very loose StreetMachine clone - without the suspension :-) I wanted USS with bar end shifters, a straight drive chain and a 700 wheel. It weighs a fair bit, how much exactly I'm not sure, but I'm going to build another one with a 26" wheel similair in style to the Vrex [hence my original question about the 16mm tubing], that would lower the gear ratio a bit and also the seat by an inch or two.
There is some good information out there relating to recumbent homebuilders. Although I did try several bents before hand, there is no way I would have been able to build mine without those sources.
Cheers Garry
Reply to
garryb59
Certainly looks like it!
Yes, I'm aware of the different kinds of steel used in bike manufacturing but not sure where I can locate the stuff [I'm UK based]...guess I just need to look a bit harder than wandering round the big DIY stores :-). I don't want anything too hard if I'm going to Mig weld it.
It was just the labeling that confused me with this tubing. As Randy says, I guess it's just basic steel tubing with a very low/absent carbon content. It certinaly Mig welds easily enough.
I'm pretty new to this world, so much so, that I've just been reading up on the processes involved in Iron Ore extraction and the making of steel. Something else I didn't concentrate on at school :-) It's been a while.
Thanks anyway..
Garry
Reply to
garryb59
You really want to use some decent material if you are going to do all that work and trust your body to the result. Maybe some of the UK readers can chime in with a source for small quantities of 1" DOM tube in the UK???
garryb59 wrote:
Reply to
RoyJ
RoyJ wrote in news:shAHd.327$ snipped-for-privacy@newsread1.news.pas.earthlink.net:
For that bikedesign I would go for a 2" tube, much stiffer and you could go down in wallthickness to reduce weight. At least I tend to push fairly heavily, so I think the boom would bend. I know of several bikes made with tubing for exhaust systems (not the lightest but easy to weld and easy to find. For the first prototype bikes I intend to use inexpensive materials and when I get all designbugs fixed its time for the quality tubes. Henning
Reply to
henning wright
What part of the UK are you in. For a lot of my materials I go to Avery Knight & Bowlers in Bath, for some more specialist materials I have had to go elsewhere. Lots of sites on the web for UK suppliers but you may have to call to find out if they have what you want.
garryb59 wrote:
Reply to
David Billington

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.