CNC Machined Trumpet Mouthpiece

By day Dr. Dave Harrison is a physician at Vancouver, British Columbia, General Hospital, where he runs the hospital's hyperbaric unit and specializes in hyperbaric and diving medicine. But at night, he dons his tuxedo and becomes principal trumpet for the Richmond, B.C., Community Orchestra.

As a physician, Dr. Harrison is in a unique position to understand the physiology of trumpet playing. While most people think that the embouchure is primarily how a trumpet player forms his lips, he recognizes that the lips, tongue, cheeks, throat and other parts of the body work together to produce a trumpet's distinctive sound. By most people's standards, Dr. Harrison is an accomplished trumpet player and musician. "Despite years or even decades of experience and practice, at some point, every player reaches the limits imposed by his ability and physiology," Dr. Harrison explains. He also concluded there could be a way to push back those limitations by changing the shape of the trumpet mouthpiece. Spurred on by an intense desire to not embarrass himself while playing Leonard Bernstein's formidable "West Side Story," Dr. Harrison began testing his mouthpiece theory in April of 2007. He started making small modifications in the profiles and lines of existing mouthpieces by hand and comparing their performance under comparable playing conditions. Forty hand-made prototypes later, Dr, Harrison says "I had a mouthpiece that improved tone and range and reduced fatigue. With one of my modified mouthpieces, a player can play longer and with greater range and improved tone." "By about June of 2007 I had determined I would need to use a CNC machine." Dr. Harrison explains. "At first I planned to get a local manufacturer to reverse engineer the rim based on a hand-made prototype, but it quickly became apparent that would not work," he adds. So he bought a CAD program and a basic CNC machine and, after learning how to use them, spent the next several weeks designing and machining different versions of the prototype. Harrison experimented with seven different variables to create new prototypes. In September of 2007, after creating 35 more, he and his brother evaluated them on a ten point scale. "We agreed on the best couple of rims," Harrison notes. "Based on those few models," he continues, "we came up with another new prototype model. We made that and continued tweaking them and making more. In the following months, Harrison began working with a local machine shop he had already chosen to produce the mouthpieces for him. "The challenge was to construct a cutting model that would mill just the rim but still produce a surface that needed a minimum of polishing and keep cutting time to a minimum to minimize production costs," he relates. Fixtures to hold the parts while they were being machined had to be consistent to .001". After playing with and testing the finished parts, Dr. Harrison made a couple of minor changes, put up a website and started production at a local machine shop in October of 2007. As business picked up, He concluded that his original CNC machine was "inadequate,". "I was spending more time troubleshooting the machine than I was designing or milling, so I started a search for a new CNC mill. I wanted to do more R&D and custom work, so I needed a CNC mill that was flexible and affordable, but also robust enough to perform precision work on difficult materials such as stainless steel. Research on the Internet led him to to Tormach, LLC in Wisconsin. After speaking to the company and several of its customers, Harrison bought a Tormach PCNC 1100 and the Tormach Tooling System in September of 2008. He uses the Tormach, which sits in his basement office/workshop, for all of his prototyping and for custom orders. "The Tormach mill easily met my requirements for accuracy, precision and repeatability, which is critical. In some dimensions, the change from one size of mouthpiece to the next may be only .005", so I need a machine that is rigid enough and strong enough to mill even tough materials like stainless steel and still give me exactly what I need." Each mouthpiece is machined from a solid block of material, usually brass or 304 stainless steel. After having it turned on a lathe to take it to its finished exterior dimensions, Dr. Harrison puts it on a Tormach PCNC 1100 to mill the rim to the unique shape that gives the Wedge its distinctive qualities. Harrison uses a CR-5 collet system mounted in the mill's standard vice. He created a variety of mandrels that fit into the collet, threaded to hold the various sizes of blanks. He simply threads a blank onto the mandrel, tightens it with a strap wrench, and turns on the mill. To actually create the finished Wedge Mouthpiece he uses either 1/4" or 1/8" two- or four-flute carbide ball-end mills. He normally runs the mill at about 4500 rpm and at a feed rate of 15 ipm for brass, and 10 ipm for stainless steel. Completed brass mouthpieces are then sent out to be polished and gold- or silver-plated, the final step in the production process. Dr. Harrison puts stainless steel mouthpieces in a Tormach Duality Lathe and polishes them with 600 grit emery cloth and jeweler's rouge. Dr. Harrison creates his designs using RhinoCad, and creating the actual toolpaths and machine code with RhinoCam. When he actually runs a part on the Tormach mill, he simply ports the program over to the Tormach's Mach 3 software and hits the start button. The flexibility and ease with which he can create and prototype new designs has enabled Dr. Harrison to add more product lines. In addition to mouthpieces for the trumpet and its cousins, the cornet and fluegelhorn, he has added mouthpieces for trombones and french horns and is eyeing the tuba market. "I've also been able to create line extensions for the trumpet mouthpieces, named for my endorsing artists," Dr, Harrison adds. "I have two new lines that are based on custom configurations created especially for them. With production started and the Tormach mill in place for additional prototype research and design, Harrison expanded his website and set about marketing his creations. In the year or so since he started production, he has developed a following of artists who endorse his mouthpieces and a substantial side business at