Sunday, September 14, 2014

Back at it on a Sunday afternoon.  No quite as many pictures this time, as you'll see.

Got the BB mounted to the ST, and put the pulley mount on the ST.

In this pic, you can see that I pulled a bit too much brass through the drive side.  But, that's better than not getting complete fill.

Then it was on to the fork.  Start by sanding surfaces clean before brazing:
Here is the steerer after prep

And the crown is now brazed to the steerer.  The crown has a ledge on the bottom that the steerer butts up to.  I cut a pair of openings in the ledge to make it easier to feed the filler wire.

This is my first fork with separate reinforcing tangs.  
There is a pocket in the crown that allows the reinforcer to slide in next to the fork blade.  

You can see the pockets here.

Here the reinforcers are in place.

Apart from more fiddly fitting, there's the question of how best to approach brazing.  

There are three (or more) different weights of metal in play.  The reinforcers are quite thin.  The fork blades are medium weight, and the crown is quite thick.  Moreover, the crown has some delicate curlicues, the points of which are sharp and sensitive to heat.  

This picture better shows how a vise holds the jig while brazing.

It's just waiting for the torch and filler.

Here its been soaked, and I've begun cleaning it up.  

I'm reasonably satisfied with how it came out.  The next one will be better.

That was it for metal work today.  However, it was time to make a repair on my alignment table.  The handles of the nut (giant), that holds the BB in place, are made of what appears to be Bakelite, or something similar.  On two occasions, this has got away from me just as it reached the end of the threads, and fell on the floor.  The whole piece weighs several pounds, enough to break a handle when it falls.  Of course, each time, it landed on a different handle.  

After each incident, I've epoxied the pieces back together, and they've seemed to hold.  However, I wanted a stronger solution.  Today I sleeved the handles with knit CF tubes, I'll probably put another layer on in the future.  Right now, the epoxy is curing under a wrap of electrical tape (sticky side out).  Holes in the tape allow excess epoxy to squeeze out as you see above.

No comments: