Can anyone give me some advice on building stems? I have been building frames and forks for about a year and a half but have never built a stem. I am curious as to what thickness of tubing to use and what do most people use for the clamp and bolt set-up? Any info would be greatly appreciated. I only use fillet-brazing but I have seen photos of custom fillet-brazed stems so I assume it is plenty secure. Thanks in advance.
You need to determine the OD of the two tubes your stem will unite. Then you get tubes that will have an ID the same as the OD you will go over. The .058 wall is normally the correct size for a pinch fit, that can be easily positioned. Pinch bolts are sold by Nova etc... and may fit out of the box or require a little work to achieve the correct fit. You braze the bolt on the tube and then slit both subsequently. .035 should be fine for the piece in the middle.
Paternek has a tape on brazing racks and stems and it is a pretty good deal. He recommends doing the joints on a mill because he says that the smallest error will be apparent in the bars, he is fine with cutting other joints on frames by hand. I have a mill so I really don't know if there is any particular reason to rule out hand work. I kinda doubt it as long as you have a means to accurately measure it, I don't see a problem.
gotta wait for shipping the lugs from either the U.K. or Australia if you go that way. Which isn't a bad way to go, but it doesn't go as well with many frames as fillet braze. If you look around the llewellyn site, you'll see he also makes fillet brazed stems