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Who has made (or knows how to make) frames :confused

What sort of tube is best to use - seamed / seamless / grade of steel (not ally :coocoo ) and what size of tube :O

Also - in the past folks used to braze the tubes together (for a more flexible/forgiving joint :confused ) like a bicycle frame .... would that be better than mig :O

Was thinking of messing around with a little 125 Honda engine I have for the kids, and if it works OK maybe trying a bigger engine :confused :devious
 

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Seamless (drawn over mandrel/DOM) and go with a 5000 series tubing (chromium alloyed). It will have increased strength over just plain old carbon steel. Any material would work, but you have to look at how it will be used. If this thing is just a mini-bike, a low carbon steel will work. If you plan to jump it and tear it up, then you will want some stronger material.

Tubing size is dependant on how you plan to work with it. I would say 3/4" to 1.5" diameter. Larger diameter will give you better resistance to bending. If you increase your diameter, you can reduce your wall thickness. There is quite a bit to chassis design and manufacturing on tubing sizes. This is one reason why bikes frames have large cross sections one way, then much smaller in another.

Brazing is not as good as welding. Brazing temps are not high enough to cause the base material to become molten. This means you are adding a liquid metal to a solid metal. You also use a filler material that is not the same as the base material. It's basically like glueing or soldering. Welding creates enough heat to cause the base material and the filler material (usually the same or very similar to the base material) to melt and fuse together. You can penetrate the base material and the joint can be throughout the base material. A brazed joint is just on the surface and the base material is not fused.

http://en.wikipedia.org/wiki/Brazing This is a description of brazing and it's attributes. I disagree with their brazing vs welding paragraph. Brazing temps are not high enough for base material melting. You are using dissimilar metals and your joint will not have the same strength as your base material. A brazed joint will not have the penetration a weld will. There are uses for brazing, but I feel what you want to do is not a good use. Welders are cheap compared to the possible outcomes of a failed joint.
 

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:stupid Yeah what he said, but i would prefer tig welding personally.
It gives a better finish and penetration to the base metal.
You can get DC Tigs fairly cheap now too..
 

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brazing is only for use (and will often be much stronger) where you have large surface area contact between the two base metals. tubing joints are not an example of this.
 

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Who has made (or knows how to make) frames :confused

What sort of tube is best to use - seamed / seamless / grade of steel (not ally :coocoo ) and what size of tube :O

Also - in the past folks used to braze the tubes together (for a more flexible/forgiving joint :confused ) like a bicycle frame .... would that be better than mig :O

Was thinking of messing around with a little 125 Honda engine I have for the kids, and if it works OK maybe trying a bigger engine :confused :devious
For a home project like a small go kart or mini bike,seamed pipe would be fine since it is common to conventional pipe bender formers.
The joints could be prepped with a hand grinder (4/4.5/5 inch ?)
M.I.G (hard wire/gas) is the most user friendly as far as hobby welders since it is more forgiving of imprecise joint fit up .

Brazing/Bronzing is based on skill levels.Many race frames (Spondon/Mettise etc) were built that way going back tot he 50/60's
Ken McIntosh stills used that time served method,they are works of art.
http://www.mcintoshracing.com/
Before that it was castings with inserted tubes....To hot and it will not work,to low and there is no capillary action.
Best left for the next project Grasshopper. :laugh

Anyone heard of Wild Willie Borsh..of course you have.!!

He would do one handed burn out's while bending the slicks getting sideway's...His engine builder used to wash the engine parts in Lux liquid and Willie was suposedly told to back off on the top end if he smelled Lux.
The chassis was built form "Muffler Moly" or exhaust tube,if he bounced it off the armco they would simply look for a muffler shop to "gas" weld a new frontend on so the story went...I guess the moral was Keep It Simple.

http://www.vimeo.com/clip:40391
 

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Discussion Starter #6
Thanks guys :hail

Found what appears to be a useful UK based forum that seems to focus on one-off stuff, though mostly "chopper" based, admittedly :dowhat

interesting stuff on tube sizes, grades, jigs, tube benders, etc., so the kids had better watch out after christmas :devious :laugh :laugh

Start of little, who knows where it could end up :confused :coocoo (ER probably :laugh :laugh :laugh )
 
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