YFBS: Day 3 - Towering and Mitering

Over the next few days, I will be detailing my adventures at the Yamaguchi Frame Building school.  The first entry can be found here.  

Class today began immediately with more tower practice, and seeing as I dreamt about brazing all night my new towers were much improved over yesterday.  I still have a long ways to go, but we were only going to be practicing for one hour before moving on to the next assignment.

Yesterday's towers.
Mitering the tubes for the main triangle was the next step in building our frames, and it was no small task.  Mr. Yamaguchi showed us the result of poor mitering, and what was desirable to look for in our tubes.  We also covered lugged verses lugless mitering, and the different techniques to get the tubes to attach well to the bottom bracket.  On a lugged bottom bracket, we were shown a technique that caused the seat tube to lock against the down tube, which Mr. Yamaguchi explained would prevent the down tube from slamming into the bottom bracket during an accident.  

So many tubes!  Some pre cut, some aero, all awesome. 
Starting to file and measure.  Lots of steps had to be taken to make sure the miter is correct and the BB stay level.
Since everyone in the class is doing a lugless bottom bracket, Mr. Yamaguchi set up a station to demonstrate to us how to mark and miter the tubes.  First, the correct side of the tube must be determined - the butted side, that is.  If both sides are butted, the tube must be measured and cut so that each side has an equal amount of butting.  If you look down the tube, it's fairly easy to see the butting (and also pretty cool).  Then using templates to mark where the tube would connect to the BB, Mr. Yamaguchi installed the tube in the vice and began to file with precision and expertise.  He made the whole process look easy, and going back and forth between a 12 and 14 inch file he soon had a tube that fit the bottom bracket shell perfectly.  We tested the miter against the BB to see how snugly it fit - however, he explained there had to be a little gap so that the brazing could still get in.  Not much, but just a tiny, tiny bit.

Mitering I was much better at than brazing.  I mitered my seat tube and down tube just fine, and then moved on to the top tube, which is a bit trickier.  Resetting the vice, Mr. Yamaguchi showed me how to angle the vice based on the angle of the seat tube, which in my case is 73 degrees.  I used a protractor to get the correct angle, and then began the initial filing.  For the finishing, a level was placed on top of the file (a number 10 this time) to make sure my file marks were completely level to my 73 degree seat tube.  You then have to cross check with the seat tube and a protractor to make sure the fit is snug and level.  I managed to get the cut correct on my first try, and was pretty happy about it!

Much harder than it looks, but rewarding when you get it just right!
After all of the tubes were cut, we moved back to tower practice, but not without a history lesson.  My classmates and I were curious about this bike, and we got the whole story.

I also had to ask about the kevlar wheels, and I was told that they were excellent, but the cartridge bearings were a pain!
At the 1992 Olympics, Lotus unveiled a never before seen bike that caused a buzz, and Mr. Yamaguchi had never seen anything like it.  Lotus was quite protective of the bike, and no one could get close to it, though everyone wanted to (apparently it was doing quite well).  Mavic at the time owed Mr. Yamaguchi a favor, and he asked if it was possible to see the famed bike.  At 2 AM there was a knock on his hotel room door - "No one's there - quick, come see it!" He looked over the bike, picked it up, and noticed a few things.  It was incredibly light, and the rear wheel was offset from the front by seven millimeters.  He, nor anyone else, knew why.  It wasn't until another night when he was working on the bikes for the track team and he heard a commotion from the Lotus mechanics that he found out.  The mechanics were shouting about the bike (Mr. Yamaguchi does a great British impression) and he went over to see if they needed help.  It turns out, the Lotus bikes were all prototypes, and not meant to stand the daily use required for track bikes.  While helping the mechanics, Mr. Yamaguchi managed to get a few answers, discovered that the bike was carved from a solid block of carbon, for one.  And the offset wheel?  "Oh, our sponsor changed - and the new rear wheel had different dishing." Mystery solved!

But that wasn't all - the World Championships were coming up, and Mr. Yamaguchi had to beat that bike.  On the flight back from Spain after the Olympics, a new bike was designed...and then built from scratch and painted in seven days before being tested for the championships.  It turns out it was a good design, beating the Lotus, getting the gold medal, and allowing Yamaguchi frames to fly the World Champion stripes!!

After enthralling us with tales of track cycling olympic days, we went back to towers until the class ended.  Mine got a little better!

They're strength tested by hitting them with a hammer.  If they fall, they fail!
Now, all of our tubes for the main triangle are cut, and I'm excited to see what tomorrow brings.  At the very least...I am kind of hoping for more snow!

Thanks for keeping my gear cozy, Chrome!!

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