Frame Building 101

[NH_]

Material manufacturers have there own tolerances, ive had some materials be so far out its ridiculous. The worst case ive had is 162mm pipe being 10mm out an the axis so basically i had 152mm oval tube and when you start having to do pipe to pipe joins you need to know what your working with is perfectly circle otherwise you have gaps when you go to butt it up.

What i meant by low amps doesnt make any difference was the UV produced by any form of arc welding is so intense it will burn you, yes it happens alot quicker using flux core then tig but tig will still burn the shit out of you if your not careful. My case it burn me through the hole in the cuff of my shirt. You wouldnt tig weld with goggles instead of a welding mask would you? so why treat your arms any differently.

The frame will always come out straight because hes using a creep resistant steel. Basically this means heat has no effect on the metal, it wont distort or the like. That is why chromoly is used to build steel bikes, not because its strong and light (its only strong and light because its thin walled, any steel will be strong and light if you get it to the right thickness). If you tried building a mild steel bike, no matter how good the jig is or how careful you are welding itss not going to be the same as when you assembled it.

 

[stacky]

Fully agree re manufacturers tolerance (was a pipe fitter/welder for 11 years) but did you need a micrometer to notice that 10mm discrepancy.

 

[Grip]

shame about all that work only to slap a cheap and poxy powder coat on it

You can't really generalise about powdercoating like that. I've seen plenty of "cheap and poxy" wet spray jobs too. And unless they actually scrape at the surface (powdercoating is much tougher than wet spray), even most spray painters couldn't tell the difference between a tradional wet spray job and a properly done powdercoat.

 

[stacky]

The frame will always come out straight because hes using a creep resistant steel. Basically this means heat has no effect on the metal, it wont distort or the like.

Run a bead down one side of the tube and say that!!
The weld metal will contract and bend the tube, or is he using creep resistant filler wire?

 

[anth69]

yeh powdercoat is tougher , but it doesnt bond like an etch primed enamel does and is more like a 'skin', once you chip powder coat it corrodes underneath and you cant see the damage to the corroded metal .... if i have something brought to me for repair/welding and its powder coated , I usually wont touch it .... chemical removal is labourious and media blasting wont touch it ... its main advantage is it's easily and cheaply applied with unskilled labour which suits some manufacturing...

 

[NH_]

Run a bead down one side of the tube and say that!!
The weld metal will contract and bend the tube, or is he using creep resistant filler wire?

That wouldnt do jack squat on creep resistent steel and if your welding something like cromoly without using a chromoly filler the weld will be terrible anyway.... with cromoly even just welding little tickets in a fillet you dont need to preset to 85-88 degrees to get it to pull straight to 90 or anything, it stays at exactly the position you tacked it to.

No i did not need a micrometer, when when your measuring small materials you dont use a tape do you. Use the correct tool for the job, Just like if your marking off large beams you dont use a 300mm ruler do you.

 

[stacky]

That wouldnt do jack squat on creep resistent steel and if your welding something like cromoly without using a chromoly filler the weld will be terrible anyway.... with cromoly even just welding little tickets in a fillet you dont need to preset to 85-88 degrees to get it to pull straight to 90 or anything, it stays at exactly the position you tacked it to.

The creep resistant filler wire comment was in jest. I am currently studying welding inspection so understand material requirements. Do try welding one side though if you ever get the chance.

No i did not need a micrometer, when when your measuring small materials you dont use a tape do you. Use the correct tool for the job, Just like if your marking off large beams you dont use a 300mm ruler do you

I am referring to the unit of measurement rather than the tool.

Edit: Sorry to detract from the thread guys!!
Some nice work going on in OZ, I especially like the square tubing used on your bike Jeremy. Nice, clean lines and strong!!

 

[JeremyW]

Almost finished

 

[No Skid Marks]

Shhweet.
How much travel?
Simple but effective design. Slight falling rate at the end?
Was it 8 or 11 speed you're running?
Will it squat a touch when pedaling?
Weight?
Side on pic please.
Ride report please.
You must be excited.
Well done.

 

[---Matt---]

Looks awesome Jeremy!

We're slowly making progress on ours. It always seems that we spend more time making the jigging than we do making the bike itself!

 

[JeremyW]

Shhweet.
How much travel? 220mm at the moment, can change with different mounting plates
Simple but effective design. Slight falling rate at the end? Will have to check rate on linkage
Was it 8 or 11 speed you're running? Will try both, 11 speed is on back order
Will it squat a touch when pedaling? Maybe a little
Weight? Not sure yet
Side on pic please.
Ride report please. In a few weeks, once I get my belt drive sorted
You must be excited.
Well done.

Will take a better side on pic soon

 

[DCGlory]

Frame Jigs

Grave dig!!

Really intreted to see some of the frame jigs you guys used while building some of these frames