Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5027035.

an alto trombone to print you can print it in 3 parts if your printer is big enought. otherwise the main 3 parts can be printeted and assembled individualy, you need to print every parts 1 time except the innerslide an outerslide connector that should be printed 4 times each.

a little demo : http://imgur.com/a/gtQBnPf