20130418

YFBS: Day 10 - Just A Hair More

I've almost completed the framebuilding class here at the Yamaguchi Frame Building School.  To read the first entry, click here.  

There isn't much class time left, so we're all working quite hard to finish our frames as fast as we can.  Having prepped the dropouts yesterday, I got a demonstration on how to properly braze them on when I got to class - the dropout itself is heavier material, so Mr. Yamaguchi showed me how he mostly heats that area and then fills in the fishtail cuts with bronze brazing.  I finished up the dropouts and my frame went in the tank.


Hangin'.
While the frame soaked, I moved onto brazing the fork blades into the fork.  Strategically drilling the holes in one of the decorative parts of the fork end lugs, I prepped the blades and cleaned everything while Mr. Yamaguchi showed me how to set up the jig for the final brazing.  My fork has a 45mm offset, a measurement that could be found by the ruler that had been built into the jig.  Once the offset was configured, the blades were in the crown tightly, and everything was aligned, I started to silver braze the fork.


After silver brazing and soaking in the tub.  
The silver brazing went fast, and once it was inspected and approved it joined my frame in the soaking tank to remove the flux.  In the meantime, I did some finishing work on my stem.  Mostly it was filing down the extra fillet, but I also filed in some half moon shapes near the handlebar clamp bolt to make handlebar installation easier and more manageable.  More filing was done, and my stem was getting more and more finished, but my frame had come out of the tank and was ready to go.


With half moons and some finishing.  
Out of the tank and polished up!
Using the wire brush, I cleaned up all of the reachable areas on the frame and the fork, which had also come out of the tank.  Brushing the frame really made it shine, but some areas couldn't be reached with such a bulky tool.  That work would have to be done by hand, so I began to finish the bottom bracket.  Thankfully my brazing was pretty clean, so finishing wasn't too much of a problem for most areas.  Alternating between various sized round files, I worked at the areas around the bottom bracket and stays as much as I could.  It soon became obvious that there were some areas that were going to be too tricky to access with the files, so Mr. Yamaguchi gave me a dremmel with a special tip to get the job done.  "Power tools are nice, but it's best to do as much as you can by hand," he warned me, "as it's easy to damage the frame with these tools."  The tricky areas of the bottom bracket didn't stand a chance, and I spent a bit of time cleaning up the dropouts and seat stays while I could.


Getting there.  Notice the clamp on the chainstay - specifically crimped for a compact crank.  Everything about this bike is very specific, and it's important to know exactly which parts will be used before building!!
At this point the frame looked nice, but not very functional, unless I was going for a track bike with the wrongest kind of dropouts.  I needed to braze on my braze-ons.


Awaiting braze-ons!
Pulling parts from a collection of toolboxes and compartments, Mr. Yamaguchi collected each of the braze-ons we would need.  My frame required brake cable bosses, cable guides, a rear derailleur cable guide, watter bottle bosses, and a brake bridge, which would be last.  The first braze on I did was the brake cable guides, which are not quite directly under the frame, but just barely touching a straightedge when the straightedge is aligned against the top and downtubes.  They're also each 7mm from the miter lines on the head and seat tubes, so I measured and marked where each would go.  Using special "doggies" that are made of nails and bronze to hold the boss in place, I fluxed everything up and set to work tacking.  


The brake and derailleur cable bosses are visible.  Starting to look like a truly functional machine.
After the brake cables guides, a tiny derailleur cable guide was brazed on, followed by the derailleur cable guides.  The brake bridge and water bottle bosses require a different procedure, which I'll have to find out tomorrow.  


Tiny little cable guide helmet dude!
All things considered, I'm actually in fairly good shape as far as everything goes - my stem is just about completely finished, I only need to do a little more to my frame, and my fork is also good to go.  Tomorrow will be the last little things and final touches.  


:D!

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