From: R.Stclair@EBay.Sun.COM (R D St.Clair) Date: Tue, 12 Jan 93 13:10:18 PST Subject: Re: And the building of my SWB begins... What are the relative advantages of TIGing and brass filleting? Tig welding is potentialy faster and doesn't require a secondary operation to clean the flux off. Brass can be a bit stronger if large fillets are used to distribute the stresses and the base material is not overheated. You can also keep going over a brazed joint touching it up untill you are happy with it. The end result can look very professional if you spend a lot of time filing and polishing. Welding creates a heat affected zone where the base metal is weakened by being overheated. This applies mostly to CroMolly, not mild steel. > Any other suggestions for how to hold the tubing in the correct positions? Sheet steel is easy to bend into simple brackets and guides that can be screwed to your plywood base. Hose clamps work nicely in some applications. A threaded rod with jam nuts and washers works well in place of the rear wheel axle to hold the rear dropouts in allignment. Bolt this to your base somehow as well. Don't worry if the wood jig burns a little. You'll only use it a few times. where should I put that rear wheel? For a SWB with a 26" or larger wheel, tuck it in as close to the seat back as possible. Otherwise you end up with too much weight on the front wheel. For a LWB, also tuck it in so as to keep the bike from growing excessively long. Even moving it somewhat under the rear seat is a good deal although it forces the seat height up which may cause problems with reaching the ground when stopped. Thanks, R.D. From: mason@asylum.sf.ca.us (Latte' Jed) Date: Wed, 13 Jan 93 01:40:38 -0500 (EST) Subject: Re: And the building of my SWB begins... Just to pop my own (amateur) advice in on TIG vs. Brazing... In my own experience brazing is good enough. My first brazes, done on my first recumbent (trike), held fine. We used CroMo and we broke many a tube (torqued the cranks off) but never broke a braze, and we'd even boiled a good bit o' nickel out of some of the joints. The machine was built as a racer but proved better as a mountain bike and has held up to jumping holding a 200lb rider. If you're experienced TIG is easier, but it's easier to clean up your amateur messes from a braze, and removing a braze (moving a tube or fixing a break) is a lot easier and neater. A brazing rig is a lot cheaper (< $100 used if you look, $150 and up new minus tanks vs. $350 [I bought one for this price, once in a lifetime deal] used to $1200 [way fucking cheap] and up minus tanks for a TIG) as well. Keep in mind that most of the very best in conventional steel bikes, lugged nd non-lugged, are brazed. An un-lugged plain brazed joint is a *lot* stronger than it looks. From: Nathan J Kurz Date: Fri, 8 Jan 93 20:03:08 EST Subject: And the building of my SWB begins... Hey there net folks! I'm back at school after Christmas vacation, and officially starting the construction of the recumbent towards which many of you have so kindly offered your advice and expertice. I got my tubing today (from Dillsburg), and that was nice since I ordered it on Tuesday. Prompt service, as all of you promised. And I got 40' of cheap mild box steel to prototype with, as well! But, as usual, I've got a few more questions for you all: 1. I spent 4 or 5 evenings over my Christmas break learning how to TIG weld, to see what that was like. Although my welds aren't always that beautiful, destructively testing them makes me think they're strong enough. What are the relative advantages of TIGing and brass filleting? 2. I'm trying to plan out how to build the jigs to hold the tubing when I go to weld or braze it. My plan is to drill appropriately sized holes through 4x4 segments, cut them in half, glue or screw one half onto a sheet of plywood, and use the other half to clamp down the tubing onto the board. Any other suggestions for how to hold the tubing in the correct positions? 3. What are the effects created by differences in wheel base? They way the my bike looks to me, I could move the rear wheel in to as short as a 32" wheel base, and as far out as anyone would ever want. I know there are bound to be some differences of opinion here, but where should I put that rear wheel? Upcoming: Monday - likely practice some more welding, design jig better, figure out how long boom really needs to be to avoid heel/wheel interference. As always, thanks in advance Nathan Kurz 95njk@williams.edu