Welding questions 4130 cromo dh build please!

cyfa2809":2p2ji1ui said:

MikeD":2p2ji1ui said:

but any tube with an id of 1"1/8th would do.

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Um. 1-1/8th is the OD of the steerer tube, not the ID of the head tube. The OD of the headset cups for a 1-1/8th headset is 34mm.

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Wouldnt that vary by manufacturer?

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02gf74":2t1klme2 said:

I cannot think of any bike frame made in stainless so there may be a clue as to why that is not a good choice. :?

from my limited knowlwdge, stainless is more brittle than mild steel hence maybe the reason why - you would presumably be using a tubing that is some fancy steel alloy since these are engineered for bike frame puposes - i..e have thin walls and correct properties, unless you want your bike to weigh a ton. .... but for downhill that is not so important (but remeber you still need to get it somehow to the top of the hill)

As mentioned, the time consuming part will be the jig so that the frame rides true and you'll probalby need to practise not only your weldig but maybe make a couple of frames on cheaper steel tubes first.

Makes sure you post photos of your progress

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02gf74":16gdernv said:

^^^ that is link to some stainless steel tubing; still not aware of any bikes being made from stainless, not to say there aren't any, just I don't know of any.

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I mean the thickness of the tubes
i.e. the outer diameter can vary?

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Dr S":3e28h0ws said:

Sounds like a lot of work to me. I can understand wanting to build a hardtail from scratch, but a DH bike ( i'm presuming you are building full suss?). Lots of machining work for pivots and rockers etc. You will certainly need more than a frame building jig for sure.

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