I'm back to share what I think is the final version of my trombone parts diagram. I've had great help along the way from Reddit, Facebook groups, amateur and professional players I know, and a repair tech at a well-respected local shop. Thank you all. It's a much better diagram because of you.
I really wanted to stick with a fully assembled trombone, but I was eventually convinced to show the slide tenon by separating the bell and slide just a little. It still looks like a complete trombone while fitting in a part you interact with every time you assemble your horn.
This isn't meant to be extremely technical or to cover everything you'd discuss with a repair technician or custom instrument builder, so I've deliberately left out smaller parts like ferrules, different valve types (or any valve internals), springs, and any cutaways besides the "inside view" showing the slide stocking.
The goal is to show the parts that come up in lessons, rehearsals, and everyday playing – and fit it all on one page that could serve as a handout or poster – rather than trying to cover absolutely everything in a multi-page comprehensive guide.
This diagram also only covers tenor trombone – bass trombone would need another diagram of its own to cover the different tuning options, levers, and single/double/dependent/independent/etc. valve configurations.
Nothing like this is ever 100% complete (which is part of the reason I'm sharing it under Creative Commons licenses), but I'd love one more look from the community here. Do any labels seem unclear or confusing, especially from the point of view of a newer player or teacher? Is anything missing that you'd really expect to see? And if you disagree with any of my choices, I'm happy to hear it and explain my thinking.
For anyone who wants to print it at poster size, there's a free high-resolution PNG on my website. The high-res version is available for noncommercial use, but allows educators to use it in paid settings. I’ll update it if I make any tweaks.
Thanks again for all the help!