Monday, November 9, 2009

Not feeling on my game today. Probably a combination of... uhh, who knows what, just didn't have it.

I worked through the vintage dropouts and fork crowns today, checking the spec and getting them ready to use on Steven's build. I'm pleased with how they came out. I need to do some final machine work on them; breaking the edges, tapping the M10 derailleur threads, cutting off the material anchor holes.

With the dropouts in hand, I set to working on developing a system for bending the stays for the project. I knew this was gonna be a bugger to get right, here's why. Most Klunker style seat stays were one of two types; either they were long stays that ran from the dropout all the way to the headtube with just a single bend to meet the seat tube, or they arched up to meet a segmented joint at the seat tube. Modern adaptations have used "tee" joints to meet the seat tube or a monostay and "tee" joint to fit the rear end together. Steven wants something that looks fluid, so I played around with some options. In the end, I decided the most aesthetic and functional design would be to use a single stay with a compound bend...rolled for the constant radius into a single lateral bend to meet the seat tube. While this will look the best and offer the strongest joint, it is also very difficult to achieve.

I spent the afternoon experimenting, working on a process to get both the lateral bend and the rolled radius without crimping any of the bends. I finally hit on a process that worked well and am moderately happy with the first stays. I'm gonna fine tune the dies a bit more and then make Steven's pair.

Here's a couple shots from today...

Making a new bending die to fit the 1.25 pivot post...
A top view of the seat stays with the lateral bend...these will yield 3 inches of rear tire space.
A side view of the mock stays in the fixture. I had to really arc these more than I had planned due to the short span from the dropout to the seat tube for a visual radius to be present. This is the bend I want to fine tune a bit before I make the final pieces.
I'm looking forward to doing up the plate fork crowns, I think they will compliment the style of the dropouts and really bring the bike together in a balanced look.



1 comment:

stevied said...

Looking really good. Can't wait to see some shots of the fork coming together.