Tuesday, May 20, 2008
dave w's bike coming together.
here's a pretty big bike, folks! it's a 26.5" top tube 29er, but it's going to look proper under dave - he's tall. so, here's pictures of the box-o-parts before scrubbing, cleaning and inspection for blemishes, measuring the butting, drilling the vent holes, and silver brazing the seattube sleeve on. next, a shot of "coping" the tubes, also known as "mitering" or super old school, "fish mouthing". then, it's all assembled into a working front triangle. the seattube sleeve is brazed onto the seattube which is then coped and tacked onto the bottom bracket shell. this sub assembly is then bolted onto the alignment table to make sure the "spine" of the frame - the seattube - is perfectly straight. seat tube no straight, frame no straight. every tube except for the chainstays joins the seattube, and the way i build the chainstays butt up against the seattube as well. you also have to slot the seatube for the seat collar to tighten down onto the seatpost and drill the waterbottle braze on holes, taking front derailleur placement into consideration. as far as frame alignment and proper brazing tolerance, the tube to tube coping fit is key. here's a shot of the BB shell/ST/DT compound miter TIGHT! lastly, dave's front triangle all tacked up. today, front triangle alignment check and on to chainstays. here's where the building gets hard...... the main triangle only has one main plane of straightness, whereas the rear has MANY. tubing list: truetemper: 1.5" downtube, single butt 1 1/8" seattube, 37mm headtube. dedacciai: s-bend chainstays. paragon machine works: dropouts and bottom bracket. 4130: 1.25" toptube, seattube sleeve, seatstays. later, thanks for reading! steve.