This was an unusual commission because it's a specialist area of manufacture where most instruments are well catered for.
Bugles are the exception to the rule though, and there is very little choice of mouthpiece for this instrument. This has long been a source of difficulty for the Armed Services where bandsmen would like to match the feel of their regular instruments when on ceremonial bugle duties.
The commission was to provide a range of six different internal geometries to suit different embouchures.
Two mouthpieces were supplied, those being at the extreme ends of the required internal geometry. Internal casts were made of those so they coulld be measured and turned into a 3D model.
Due to the large number of operations and different tools required to machine these parts, I designed the tooling system pictured below. This comprises a steel plate that's located on dowels and can be set to the machine zero. The six ER32 collets mounted on it are used to hold drills or boring bars, while the lathe tool holders on the left perform the turning operations.
The chuck for the milling cutter was replaced by a small three jaw chuck that held the brass blank, thus turning the machine into a pseudo CNC lathe with auto tool change.
A windows utility program was written using RAD Studio to convert the CAM output into a form that took the various tool offsets into account. This allows a tool offset file to be simply edited to obtain the correct diameter for each tool. The offsets of the ER32 chucks are of course fixed but need to be applied to the correct operations.
The method has been gradually honed to make this a quick and effective way to produce complex geometries or to ensure repeatability and speed of production when making larger quantities of parts.
Trombone mouthpiece with
selective gold and silver plating
Bugle mouthpiece as machined
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