Thursday, September 06, 2007
more notes on framebuilding.
here's the progress on david's frame, almost done except for the seatstays, a whole little project of their own. got all the nice shiny tubes from the last post all mitered up and stuck in the jig. the jig is fully adjustable to any normal geometry and holds the tubing straight so you can tack them into a structure. you only tack in the jig, you do not fully braze in the jig as you cannot achive all the proper angles to join the frame while in the jig. brazing of the frame is done in a park repair stand. also, here is a pic of my mitering setup. it's a vertical mill-drill. it takes hole saws of the sizes of tubing you are joining to and copes the tube to fit it. the tubes are held in a tubing vise, which is bolted to a rotary table, which spins to the desired angle and clamps fixed at that angle. also, a picture of the chainstay fixture, it hold the stays in place so you can braze the dropouts in place after you slot them and then miter them both on the same plane. and, here is a couple pics of making stay bridges, i cut them out of cromoly strips with a hacksaw, rough them into shape with a bench grinder, and finish them with a hand file then braze them into place in the jig to hole the stays parellel during alignment. lastly, a pic of the frame in it's current stage - looking like a bike! more later, steve.