Tuesday, April 1, 2008

Don's bike is in high speed...

Bike two for this week, Big Don from the dualing states of CT and NY is hooking up with an internally cabled geared 29er for his main ride. This beauty will be outfitted with XTR drive train, Phil Wood hubs, Magura Marta hydraulic brakes, Thomson post and stem, and matching Luv Handles.

Should be a pretty trick build.

Let's start out with a pic of the internal cable guides looking through the down tube from the bb.

After slotting the tubing in the butted sections where the cables enter and exit, I then fit brass tubing in the piece that will fully encase the cable allowing for a rattle free ride with easy cable routing. Everything is silver brazed in place and finished smooth. In the above pic, you can see how the internal pieces are positioned once in place

And a quick pic below of the entrance point...

After all the internals are placed and the ends mitered to fit for the main triangle, it's time to put it under the torch. The majority of the tubing on this build is 8-5-8, meaning it is .8mm thick on the ends where strength is needed and .5 mm in the long center section to reduce weight. Though thin, with tight miters, you can run a tiny tig bead that will dissapear under the paint, giving a seamless clean look.

Here's a couple pics of the welds on the bottom bracket area, a challenging spot due to the varying angles of intersection and the disparity in tubing thicknesses.

and here is the main triangle all welded up and ready for some rear end attention :)

I start the rear end by working on the chainstays. I mill the dropout end first, cutting it in two planes for the angle from the dropout to the bb and the offset so that the tubing wraps around the shape of the drop. I then tack the two together to give some strength and stability during mitering the bb end.

The shot above shows the mitering end of the Anvil fixture. The scribed lines indicate the bb centerlines so you can position the intended placement of the chainstays once everything is all cut up.
Dead sexy curves on those chainstays. Is it wrong to get that excited about a bike?
A single cut to length is all it needs once set up is appropriate.

Moving on to the seatstays, I custom bend them to fit my design. The pic below shows two correctly bent seat stays and one that I pushed too far and the wall collasped...bummer. I hate to waste product and money, but every once in a while the demands we put on the material is greater than it's ability to support our expectations :(

Mikey, whose SS coupled frame is documented below, stopped by to refine his wheel building skills under a watchful eye. Despite a few false starts, he cruised through the lacing portion and will be ready to tension and true on Thursday when he stops back. That's when the real education will begin ;)

Next day in the shop should see the end of fabrication on Don's niner and the beginning of the last frame before I head south.

No comments: