By James Morikawa
27 September 2006
This webpage will be on — as the title goes, ". . . BRAZING THE SEAT-STAYS". I've completed the welding and brazing of the chain-stays, which I briefly covered on page 10.
Pictured below, I've positioned the mitered seat-stays on my Henry James frame fixture. I always recheck the alignment of the un-brazed seat-stays as they sit in the fixture; using the the alignment-checking-tools I previously described.
I silver-braze the joints. I do this with frame-parts mounted on the frame jig.
I can't say, "I'm a good brazer" — cause I can sure as hell create some shitty brazes when "I'm out of practice". You see that top fast-back joint — I can get a better flow of silver-braze inside the tubes when I purge with argon — creates a nice internal fillet on the inside of the stays. The Argon gas seems to further the anti-oxidation qualities of the flux — and keeps the insides "nice and shiny".
OK, and it's time to check, and re-check alignment. I'll be checking for wheel-center-alignment. I want that rearwheel centered between the stays. I found it's not the easiest thing to get done.
The above pictures don't show it, but those two tools are flipped over for frame-centering, and wheel-centering. To make it clearer I'll post some pictures below.
An example of checking for centering-alignment — check the right-side with the tool — flip the tool over, and check the left-side. I want minimum difference in the gaps between the tool's straight-edge and left and right sides of the seat-tube. I hope the pictures describes things. The other tool functions in the same manner, and checks for wheel-centering between the stays.
In the above pictures: I needed to do some rear-triangle alignment, and that's on my trusty Henry James Alignment System.
In the picture below I'm rechecking the wheel-baseline to seat-tube center alignment, and wheel-center-alignment.
If alignment is not good enough I need to correct them at this point — before I continue now.
An aligned rear-triangle should remounted smoothly back on to the frame-jig — with the jig dialed in to the exact frame specs — without forcing.
That's it for this page. Goodbye.