Wednesday, July 20, 2005 to admit its getting better, its getting better all the time

Well, work has begun on version two of my French inspired frame. Like the last version, it's made up of Deda Uno O/S tubing - but this time I'm using HJ lugs and BB. The later has the built in cable guides, so we'll see how they work and how the paint holds up around them.

As you may recall, frame #1 didn't pass inspection. It's likely that I can redo the rear triangle and have a good frame, but due to timing and schedules (including vacation for my painter's family and for mine) - I will get to a completed bike faster by starting over. Frame 1 will get repaired and painted yet, but just not yet.

Now, having built 3 forks already for this frame, I should be able to save on the effort of making another one. And for the present purposes that's true. However, I want to try a HJ 3degree crown with some Reynolds pre-bent touring blades to see how close that comes to giving the requisite 61mm rake. But that will happen somewhere down the line. For one thing, HJ is temporarily out of stock on the crown, and for another, I'm out of pre-bent blades.

Last night, I did the lower headtube joint. The lug got prepared prior to dinner, then the down-tube was mitered and the joint brazed after diner. BTW, one change on this frame is a decision to go all silver. It's easier for me to work with....I'm going to practice brass on some more cheap lugs before trying it on a frame again.

The HJ lugs seem an interesting contract to the Walters that I got from Joe Bringheli. Put simply, the HJ need less work on the inside and more work on the outside.

For those who have been following this blog, the Walter head-lugs were too large in diameter around the head tube to silver braze. I also found them stiff and couldn't adjust angles on them without destroying the roundness of the spigots. Finally, for other joints, the lugs were "tight" and needed to be opened up some to fit the tubes. But, I didn't need to do much of any cosmetic work on the outside - they were nicely finished.

The HJ offered good fits out of the box (bag?). All that the insides needed was a good sanding to clean the surfaces for brazing. On the outsides, there were lots of seams from the mold. This called for a little elbow grease. The lugs also have their "degrees" cast in and this too needs to be cleaned up (unless you don't adjust the lugs and want to remember the measurements on a frame).

As is now my common practice, I pinned the tubes, fluxed things up, and started the braze. Troy suggested that I try his approach of heating the last point in which the silver will flow first, and working back toward the point of entry. So, working slowly to heat things up without scorching the flux, I worked from the bottom (physical relative to how the piece was clamped) up. The results were great. Along with the changed sequence of heating, I'm getting better at recognizing when the silver has pulled through - and am willing to move the flame away and take a closer look before putting any more silver into the joint. All of this paid of with a really clean joint. Does it look like the pictures that Sachs posts? No (well except for a little area). But, there was only one small area of shoreline to clean up and even this was well below the surface of the lug (making it easier to clear the silver without damaging the lug). The overall cleanup of flux and silver was just about the shortest step of the process, rather than the longest step (by far). Yea!!!!!

How did my lug differ from a Sachs? Well his pictures show that he generally has just a slim line of silver showing at the edge of the lug. I has some spots like this, but more spots where the silver flowed up to a quarter inch away from the lug. The thing is that this was all a very very thin coat of silver. I had one area away from the lug that need a minor file and this area was smaller than the end of an eraser on the end of a pencil. Cool. Also, on the bottom face (where the headset cup rests) I had a thick blob of silver most of the way around. This should disappear when the head tube is trimmed and faced - so I'm not worried about that. I got a lot here drawing silver to a point where the flow seemed to have been partially blocked by a pin and this point was also furthest from the source of the silver (front of the lug band that goes around the head-tube). I could have cheated and applied silver here from the top side of the band, but I was trying to limit how many sources the silver came from. Using careful pin placement next time should help alleviate this problem.

Tonight preped the bottom-bracket before putting the kids to bed. Afterwards, I mitered the down-tube, cleaned things up, set the pins and fluxed the joint and went on to braze. Using the same technique as above, I may have got a little excess silver into the BB, but the joint is quite clean. I'm feeling like some real progress is being made.

Hopefully, tomorrow will see the seat-tube installed and any adjustments/alignment done. Then Saturday I can spend getting the top-tube in and Sunday can be spent making sure I have adequate jigging in place for making up the rear-triangle. With any luck, I can deliver this to Troy between his and my trips, and see a finished bike in a few weeks.

Good night.

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