Fork, Part 2

Had some time to work on the fork this week.  The fit up on the crown was a bit on the gappy side, so I went with 50N silver instead of my customary 56%.    

56% flows faster, melts at a slightly lower temperature, and I just generally love working with it.  

50N is a bit thicker, and a bit more sluggish.  It has a few advantages: it will fill larger gaps, it will form small fillets for strong joints on brake bridges/other high stress braze-ons, and I'm told that it wets out more easily on stainless steel than some other silver alloys.

The downside is that I just haven't gotten the hours in with it to feel totally confident when it's necessary.  I ended up doing a second pass to make sure I had good penetration, and definitely crisped some flux near the end (should have let it cool down and re-fluxed it instead of heating it right back up).

That said, I think I'm going to stick with this one.  I was able to draw the silver through to the pins, and I think it's unlikely that I have a bad fill.

Here's the crown all cleaned up.  I love Henry James' crowns, they have this beautiful elegance to them.  I can't wait to see it with some paint on it.

I also love hourglass spindles.  I set these up to work with Nitto/Rivendell's Hub Area Rack.  It's a gorgeous piece of gear.  I can't imagine actually needing four bags for the kind of riding that I do... but WHAT IF? 

Worth mentioning: I used 50N for these rack mounts too.  Note the nice little fillet around the base of each of them.  

Here's the whole thing.  It needed a bit of a twist, but I've gotten it pretty straight. 

Bonus image: my co-blogger, Gimble.  She gets her own chair.

Fork, Part 1

It's been a loooooong time.

Over the last couple of years, I finished the bike I was working on, made a sweet single speed, and rode them both a bunch.  I made a lot of progress with my brazing, but still count as a dangerous amateur.  

I've done a few practice forks, and I think this one will turn out well enough to bomb down big hills on.

First, I trimmed the fork down to the right diameter to fit the Llewellyn dropouts that I'm using.  Then I used my home-made blade bender to add a nice smooth bend.  The block was made for me by a coworker out of some scrap wood at his other job repairing boats.

I'm using 1.0/.66 True Temper blades.  As a Dangerous Amateur (tm), I really like these.  They bend easily and are pretty forgiving when I have to mess with them.  The folks at Henry James are always a pleasure to work with, and if I mess up I can get replacements pretty quickly.

48.5 mm rake on both blades, perfect!  The bends are also pretty close to perfectly in-plane.  Next step, fire!

For this bike, I have my own brazing setup.  It's oxy/propane, and the oxygen is drawn from the air by a medical oxygen concentration.  This way I don't have to deal with oxygen tanks or acetylene, and the slightly more diffuse flame that the propane makes actually feels a lot more natural for silver brazing.

I started by attaching the fork crown to the steerer tube.  I've gotten a lot more patient with practice and have stopped burning much flux.  I pulled through some excess silver, but a swipe or two with a stainless steel brush  while it was still hot got rid of most of it.  The rest should come off in a few minutes with emery cloth.

I didn't have time to start brazing the dropouts onto the fork, but I did spend a little time adjusting the jig.  I bought it from someone who'd already adapted it to accept an anvil axle, and with a few extra measurements, it turns out pretty awesome results.

Ok, it's been a while since I've written an entry, so I'm out of practice.  Please accept this blurry picture of a puppy I want to adopt as a show of contrition.