Donor bike question: CroMo?

[rykoala]

Hey Brad and folks,

I bought and downloaded the Meridian plans this evening. I read them in full and I am SO STOKED to get going. I have some donor bikes all ready to go but unfortunately the only 26" donor MTB's I have are of 4130 (CroMo) steel. Do I need to find a mild steel bike instead? Or, will it be a problem to use just the bottom bracket from the CroMo bikes? One is a 1992 Trek 820, the other is a Specialized hard rock or something from the early 90's.

I'd use the mild steel BB's I have but they have American 1pc bottom brackets. I want a 3pc! ;)

Thanks a lot!

[TheKid]

I made mine with cromo front forks and rear seat stays with no problems. Basically, I tack welded everything with many tacks before "connecting the dots" to minimize the chance of burn through. Work from side to side with the tacks so they have a chance to cool before going back to the same spot. Most bikes are cromo these days, and I find it hard to find mild steel frames except for maybe rear suspension triangles. They seem to be much heavier than standard triangles, but I don't know if it's mild steel or heavier guage cromo.
By all means use the BB's for 3 piece cranks. They're a much heavier guage than the rest of the frame, so burn through is rarely a problem.

[rykoala]

COOL. I am going to use one of the cheapo bikes for everything but the BB and the seat stays. I want to use the seat stays because they'll have the canti mounts for my rear brake. I don't have the stuff for disks yet.

I cannot wait to get started! :)

[TheKid]

I was in a hurry to finish and went with the rear canti brakes. Along with the front canti's, there was plenty of stopping power, enough to make the bike skid as required by NY State law.

[rykoala]

I am planning on rear cati's or linear pull brakes, whatever I can manage to afford. I will be using regular caliper brakes on the front, unless I get good enough at welding on the thin stuff that I can weld on canti mounts.

I still have a few smaller projects to do, mainly cleaning and organizing my garage. Then my son gets a little downhill racer type thingy, which I promised him. I am having a tough time deciding how I want to do the front axle though. Should be fun figuring that out. I am thinking a piece of EMT with kid bike axles welded to it and 20" kid bike wheels put on should suffice if I don't screw it up too bad LOL.