I have a fillet brazed cross bike in the works right now, and thought I'd share a look as things progress. I made the seat tube reinforcement today. When fillet brazing with a standard sized seat tube, it's a good idea to add this piece. The walls at the top of the tube are thin to make way for a 27.2 mm seatpost, and this sleeve will make it quite a bit more substantial without adding extra weight to other parts of the tube. It starts with straight gauge 4130...













... and ends looking something like this. The tube used to cut this out of has an inner diameter that is near perfect for silver brazing clearances. This will be brazed on to the seat tube, and a breather hole will be drilled in where the top tube intersects. Locating off of that hole, I'll then make the down tube/bottom bracket miter on the lathe.

Labels: Building, Cyclocross