Tuba valve cap extender

thingiverse

This is an extender sleeve for a Miraphone 186 CC tuba rotary valve. It screws onto the bottom of the valve and provides space for an Apple AirTag(TM) between the bottom of the valve and the screw on bottom cap. It prints in two parts. The first has an internal thread that screws onto the valve body. The second has an external thread to accommodate the existing nickel-silver valve bottom cap. The second piece slides into the first and can be glued in place with any CA glue. I sanded the exterior, applied some primer and spray painted it in a metallic brass color. The threads are metric .7mm pitch and are quite fine. I was frankly surprised that my AnyCubic Vyper was able to successfully print this fine pitch. The threads don't turn out well if they are on the bottom in contact with the printer bed. Hence the two pieces so each can be printed with the threaded section at the top. I find that I get some shrinkage using the MatterHackers PLA Pro and had to adjust the diameters by trial and error until they fit the existing metal parts. I expect that there may be fitting issues requiring adjustment when printed on another printer or using different filament. The photos show it mounted to the 5th valve on my tuba as its bottom cap is actually on top allowing for a clear photo. In practice, I expect most people will prefer to install it on one of the other valves where it is almost unnoticeable.