I got a couple of emails telling me that the 1.5D mouthpiece didn't exist. And 1 that said the standard Bach and Schilke pieces used the same throat.
Those statements are not completely accurate.
All Bach sizes have always been available in more depths than just the standard C cup. No it isn't going to be in your local music store. However; Mouthpiece Express carries some Bach sizes in A, B, C, D and E cups and a F. They charge 43.99 for any cup depth. Then you have people like Mark Curry who cut the Bach sizes in 10 different cup depths for the standard price. So yes the mouthpiece does exist in the Real World.
Even with an odd size the D cup has always been available as a special order. It is a very common thing for college professors to put a player on a D or E cup when the student first tries a piccolo trumpet.
I picked the 1.5 because it isn't as popular as either the 1 or 3 yet it is a popular diameter in other mouthpiece brands. Bach never pushed that mouthpiece much. I wanted them to think outside the box. When I was in school lots of players special ordered pieces. Now it is almost like they don't even know that can be done. I guess it is because they will look at a mouthpiece chart and say they don't make this size. However; the truth is that they DO make every size. Some of them are just not kept in stock.
I thought I addressed the fact the piece wasn't going to be readily available when I suggested that Curry Mpcs made 10 depths for every diameter.
As for the throat of the standard Bach and Schilke both being labeled a 27, he was correct. Yet they are not exactly the same because the 2 brands are different at the shoulder (in how they start and blend the throat into the cup) and it does affect how the piece feels. I just used the generic idea of the throat because I didn't want to explain what the shoulder is and how it affects things. Staying within a brand usually keeps that the same but switching brands often changes it.