One Piece Precision Bb Return.
There are a few different ways to make and fit up the Bb return on a Geyer valve section. Some do it in 2 and some in 3 pieces, but very few makers/ companies take the time to make it in 1. It may seem like a minor thing, but it eliminates one, possibly two ferrules on the valve section. A ferrule joint has the potential to introduce a few different problems;
- Unintentional burrs on the inside of the cut tubing which disrupt airflow
- Narrowing of the tube cause by the shrinking of the cooling solder
- Slight skewing of the tubes under the ferrule (i.e. the tubes aren't flush or are off center)
- Air leakage over time if the solder joint is under filled
Also, a one piece Bb return lays flat across the Bb side of the horn, allowing for it to be soldered to each of the outer valve slides on the Bb side.
The reason that it is so difficult to bend this branch is that there are multiple angles and planes that must be correct in order for the part to fit. Also, bending a 90 degree angle without oval-ing the tube is complicated and requires a few intermediate annealing steps.
Fine tuning the fit is also difficult and time consuming. I always dry fit parts to make sure that the tubes hit their ports perfectly without having to pull or clip them together. These last two pics are of the Bb return laid into place without clips or wires. They hit the ports perfectly and to install this part, I just slip ferrules over the joints and solder.
July 31, 2012