Saturday June 5, 2010
I keep putting off postings – waiting for future photos. . Well, i’ll have finished photos when this bike comes back from paint, but here is a bit on “domed stays.”
i got a request on a bike for domed stays with stainless Paragon Track Dropouts. The dropout is made in Richmond, California, by Paragon Machine Works where all the finest machined frame brazons and parts are made.
These stainless dropouts are also the stiffest!! Terrifyingly stiff and not really a friend to the silver brazer. Set your dropout angles in the vise before assembly and take care when you adjust them (just get them right the first time).
Today I offer a procedural, as I recently refined my procedure for doming stays where they meet the dropout.
To make the domes on the stays, I start by cutting a birdsmouth in the end of the chainstay. i use the mill because i can, and it gives me a nice symetrical start.
Then I file a round key into the birdsmouth. This file is actually just a bit too large, but worked fine. The key allows the metal stretch and form without binding or cracking.
Then I anneal the end of the stay with a feathery flame (heat it till it glows a dark red and let it cool slowly- sorry no photo), and go at it with the hammers. gently.
I tap and pound them over gently into the desired shape, being carefull not to stress the metal unduly.
Then I recut the slots (most easily and cleanly done on the mill, but up until recently it was all hack saws and files). Take care to cut the slot past the work hardened area so that the seem of the joint is in relatively unaffected metal.
Then I file and fit the drop out.
Saturday June 5, 2010
Pacenti was out of the standard PBP crown, so my last run of forks all got the stainless version. I regretted it a bit in the midst of finishing 4 stainless crowns, and then perused the Klingspor catalog for the right finishing product to make the job easier (there were plenty), but didn’t make any orders.
Here’s the last to get finished:
And here we have another 3 recent frames before final finish work:
Wednesday April 14, 2010
The satisfaction of getting this one out on the road was hampered by some frustration with the Sram S7 hub. It comes with continuous housing and I checked it all out and thought, oh yeah, I can reinstall the cable,etc. of course. But the SRAM S7 baffled me, I hate to say it.
The chainguard is a simplified version of the one i featured before from blackbird SF. It’s mounted to 5mm bosses on the down tube and seat tube with fender hardware and turned down 5mm bolts. It’s sized to a slightly larger chainring.
It’s very upright and is a quick responsive Bike. The upright posture doesn’t load much weight on the front wheel and it can at first feel a little squirrely. That’s something I love about mixtes.
Looks nice on a postcard.
Thanks to Alfie for the help on the photo above.
And this photo.. . was taken with a broken sigma lence mounted with fish eye plastic lens from a projection television found on the side of HWY 9, low quality plastic lens, very scracted, high iso, small aperture. Nice huh? . . .
Photo quality has been going down recently.
Sunday February 7, 2010
I raked blades for 3 forks today, and the new mandrel is awesome. I came to it’s design thru the use and modification of 4 previous iterations of wooden mandrels, advice from other builders, and a desire for the “coolest looking” and highest performance blade shape.
The radius is small and the bend is near the end of the blade because the style of those old overly raked forks is unbeatable, and placing the offset down on the smaller part of the tube takes better advantage the fork’s ability to flex and absorb shock, and places the bend where the tube diameter is smallest and the wall thickness is greatest.
Saturday February 6, 2010
Raking fork blades just got easier!
these dramatic photos by Joshua of California
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And here are the results!
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