Tuesday, August 26, 2008

Starting the front triangle

Here's how I like to start the front triangle, the down tube to head tube connection. All the frame's geometry follows this angle, so it's important to get it right. A perfect fit, with no gaps in the miter is essential for maximum strength and alignment. For this frame, the angle has to be 58.5, a typical angle for a smallish frame and only half a degree off from the angle of the lug- just a tiny bit of tweaking and it will all go together perfectly. A light-tight fit done with only a hacksaw and a file.
All brazed up! It looks like hell with the flux still on it, but trust me, it's a nice braze!

Lining up the angle with the blue print- spot on! If it were off, I'd have to cold set it (read: bend) something I absolutely hate to do and something I haven't had to do since my first frame. If the miter is right and the proper brazing sequence is followed, it will be right every time.
You can also see the water bottle bosses have been brazed in too- this is another one of the little things you do to before the frame is together, it makes it easier to maintain alignment later on. Building frames comes down to the millimeter, so every little bit helps!

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