TromboneChat

Hello!

Just doing a bit of comparative analysis on my current and past equipment.

For many years, I played a DE LB114, M, M8 bass trombone mouthpiece. I get that it's a Schilke 60-sized (1.14") rim, but does anyone know the backbore measurement? I don't have the equipment to measure it.

Thank you!

Bach50b3 wrote: Thu Jun 18, 2026 7:56 pm Hello!

Just doing a bit of comparative analysis on my current and past equipment.

For many years, I played a DE LB114, M, M8 bass trombone mouthpiece. I get that it's a Schilke 60-sized (1.14") rim, but does anyone know the backbore measurement? I don't have the equipment to measure it.

Thank you!

You can measure the throat (i.e., the ID at the narrowest place in the venturi), but the backbore is pretty much the entire inside of the mouthpiece from the venturi to the end of the shank. There's no one place to measure. That's why Bach lists a (proprietary, AFAIK) reamer number rather than a dimension for backbore.

The throat is .295
My backbores don't really compare to any others, and every backbore is different, specifically designed around the cup it goes with, and the bore size it's designed for. I don't use the same backbore with different cups the way most others are.

Hello, Doug! Thank you for the response.

I find it fascinating, and logical, that you design each backbore with its specific cup in mind.

That said, this explains a lot about how I feel when I play your mouthpiece compared to others. Thank you for the information.