Delayed update

While waiting for my flight to leave Chicago I decided to start at the beginning and recap the week. I also thought I write a better written summary of the week than what I have been doing.. I’ll spare the details such as where we ate, drank beer etc… This last week really was frame building 101. I think myself and my classmates all had a need to start at the beginning of the frame building process which is fit. We could have just mitered joints and filed away but each of us has a desire to build more than one bike, either multiple bikes for ourselves or others. My interest was/is how does one go from the physical measurements of the rider to a frame that is built rationally. Should I take the measurements off another bike and copy them? Could I make a bike fit better? What should I do to fit my wife who has long legs and short torso? After the last week I’ve decided that frame fit is one of the most inexact parts of frame building for two reasons. No two bodies are alike and component choices are a huge variable. I think that is why frame builders want to know what the current ride looks like. The current ride is the best starting point to use, and maybe very closely copy. Last week Dale Brown asked me if I had made a drawing of the bike I was going to build. I told him no, and that Doug Fattic does not use drawings and he was teaching us how to build without a drawing using his layout fixture. I wasn’t sure in the beginning how Doug builds without a drawing, but I intuitively liked the idea. Dougs fixture allows the builder to set fixed points such as bb drop, standover, seat height, steering axis, fork rake, lower head lug placement, bar height distance from seat and probably one or two more I have written down. Once those points are fixed, tubes can be mitered, lugs fitted to connect those points to fill in the frame under the rider. I have heard Richard Sachs say something to the effect that the three contact points of the rider drive the design, not the angles or tube lengths. I know what he means now. Doug’s fixture allows us to do just that. I think a drawing would force us to stick to a rigid plan. With Doug’s fixture we were able to play with different combinations and ways of getting the same fit. Ideally I think the method to use is to layout the rider measurements in the fixture, then select lugs and tubes to best achieve the desire dimensions. I plan on building a jig like this soon. Our next step was to miter the tubes. Doug Fattic is a machine guy. His Bridgeport mill has an easy to use fixture that allows a mitre to be set up and cut in just a minute or two. Doug uses hole saws in the mill to mitre tubes. I don’t know if he cuts heat treated steel tubes or not but it worked great for my Columbus SL tubeset. I suspect his fixture and mill are both so rigid that it doesn’t matter much. It would have been nice to file more, but in the interest of time we needed to use the mill. We got our measurements for the miters from the layout fixture and what we knew we needed. When the tubes were cut we fit them on the layout fixture with lugs for confirmation of fit. I have already written about the spotting/ tacking/ brazing alignment process so I’ll skip that step. The next step was chain stay fitting. Doug had me braze in one stay with the Anvil Jig and one stay using a standard alignment gauge and a straight edge. It was simple but not always easy. I think that a jig out of 80/20 would be easy to make for this step as the alignment is checked and fixed at each step as in the main triangle brazing. After chain stays I moved to seat stays. I am using the sweet Columbus double taper stays that came with the SL kit. With the skinny profile of the stays a 11mm stay pug was the way to go. The problem was that the hole in the stay was too big for the plug. Big enough, that the silver could not fill the gaps. With Doug’s consultation I went to work doing what I love, machine work. We found some steel rod slightly larger than the inner stay diameter. I sanded it down to a slight wedge that would fill the stay but not drop in completely. I cut the piece off long and brazed it in. I cut what was left out of the stay off, squared the edge and did the other stay just like it. Next I used the beautiful machine, the lathe, to bore the stay the precise diameter needed to braze the seat stay plug in. After brazing the plug it was clean up time. The week was over and I didn’t complete the frame. I’m a little disappointed that I didn’t finish the rear triangle. I’m a little nervous how it will travel. I’m unsure of how dimensionally unstable the frame is without seat stays. I am thinking I maybe should have tacked the stays to travel but that extra heat might have been unfriendly on the alignment anyway. I would have liked to be able to show off a complete frame. I did leave Doug’s with the skills to finish the frame and tackle problems as they arise. It might actually be a blessing as frame building doesn’t seem to be a team sport and I think I need to build without a safety net . I haven’t said much about my classmates as they didn’t take the frame class to be characters in my blog. Scott, Ernst, Robert and Mitch are really good guys. Mitch has a desire to be a frame builder and I think he’ll get there. He has a quiet, focused determination that inspires confidence. Ernst, the Flying Scot, was the humorist of the bunch. He coined our group nickname, the “Fluxing Gassholes”. And being true to his heritage he’d try to cajole us into ending the day at the pub. Scott is like me somewhat. He wants to improve himself. He is quite skilled with Machine tools and works with his hands well, both better than I do. Robert is the least obvious frame builder out of the group. He works in Manhattan, lives in the burbs, has two kids and a very professional wife. He is a graphic designer, but feels the same calling as his grandfather and great grandfather who were both Machinist. Robert is a rock solid person and was fun to have around. Best of all he rides a track bike everyday on his lunch hour in Central park. From here I want to finish the frame quickly. I haven’t decided on paint yet but it will probably be a three color paint job. Mike Swantak is helping me do the decals. I have some ideas that might be interesting. I board in a few minutes and once on board I’ll start sketching some fixtures I want to build. Later I’ll be posting a link to my yahoo site with pictures of the class. Most of the pics are not very interesting, but will allow me to recreate the process. Later, JG