Monday, November 16, 2009

Tri-plane fork...working in some kinks

So I take one day off out of the shop in three weeks to take some stuff to Pa and ride with some friends and as soon as I hit the parking lot...

"Why aren't you working on my frame?"

Who'd thunk, but Stevie D. just happened to be at the same trail head to ride the same trail at the same time as me...even though neither of us live anywhere close by. Surprised the crap out of me. Such is the cruel irony of building for others, the burden of keeping projects moving never leaves you. Fortunately, I bonked to the point of near hysterics, so that over whelmed any guilt I was feeling :)

So, the last two days I've been working in the shop to keep Steven's highly custom frame moving forward. A number of fixtures needed to be made to bring the fork crown fabrication into reality; an indexed flat crown bender, a mitering fixture to locate a origin point hole for the second operation bends, and a fixture to hold the bent crown for final milling of the 1.00" fork leg opening. All those special pieces take a bunch of time but will allow for excellent repeatability and efficiency if I choose to make more of these.

A shot of the bender. The center 1.125 steerer hole locates over the top of the circle and is clamped down by the square stock sitting on the vise, allowing for the bend to be placed equally on both sides of the crown.
The crown is then taken out, the bender reset for the leg portion, and then each side is bent again. Here's a shot of the final leg bend being placed, you can see the almost complete crown just below the bending arm...
The first mocked up piece...the angles are a bit steeper than what I want. I'll run another and then scribe a point on the bender or add a stop screw to indicate the appropriate distance for each bend.
A quick mock up on the steerer. I played with 4 or 5 spacing sequences and am still not decided on where I want it to be. This shot is a tighter configuration than the original drawing.
Despite my best effort, these projects always take longer than anticipated. I'm sure that it will be worth the effort though when the finished bike hits the dirt.




Anonymous said...

Can't help but notice that Terry Larrazabal sticker...where did you get that?

Rody said...

The sticker came from Goyo, Terry's son. I built a bike for him for the 2009 NAHBS show and he was kind enough to share the story of his father, the impetus of the festival, with me. You can see the build process for Goyo's bike on the Gallery page of the web site



DC said...

That fork build is going to be sweet!
On the spacing, my only comment would be to leave enough room to get a rag or park brush in there to clean between the plates.