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Spinning a Bell

Spinning a Bell

Bruce shows off his artistic touch.

In this video you can watch as Bruce spins a trombone bell. The spinning of the bell is one of the final steps in the manufacturing process and is when the bell begins to take on it's final shape. All Getzen trombone bells are two piece bells and at this point in the process the stem and flare of the bell have already been brazed together. All Getzen bells are spun in a very similar fashion with exception of one piece trumpet bells which require much more time and attention.

Step 1: A small amount of lubricant is spread onto the bell blank to allow the spinning tool to evenly flow over the surface.

Step 2: Next, a small wooden tool is used to roll the edge of the bell rim over slightly. The roll is formed to add a little rigidity to the bell flare. This prevents the flare from "wobbling" or coming out of round during the actual spinning.

Step 3: Pressure is applied to the bell using a specially designed spinning tool. Notice how the brass moves as it is tightly formed to meet the shape of the mandrel, especially around the bell flare. At this point extra attention is paid to smoothing the seam between the flare and stem. The final pass with the spinning tool is done slowly to ensure a smooth and even surface on the flare which Bruce easily checks by hand.

Step 4: After pushing brass from the stem and out through the flare it is now necessary to trim the excess from the outer edge of the flare. At this point only a small amount is actually removed. Later, when the bead is formed on the bell rim, it will be trimmed to the exact size needed.

Step 5: Again, special attention is paid to the flare/stem seam. At this point, excess braze material is scraped from the surface.

Step 6: A file is used to remove tooling marks on the surface of the bell caused by the spinning tool. Next, emery paper is used to smooth out and remove any cut marks left by the file. This prepares the surface of the bell for later buffing.

Step 7: Finally, Bruce gives the bell one final hand check for any surface irregularities.

Bruce has been spinning bells for more than 15 years. His years of experience enable him to make a very difficult and daunting task seem easy and routine.