There is no Morse Taper for Flugelhorn.
Large end = .3561"
Small end = .2520"
Length = 2.00"
Taper/foot = .6246"
Taper per inch = .0521"
Angle from Center = 1.4908
Large end = .4750"
Small end = .3690"
Length = 2.13"
Taper/foot = .5986"
Taper per inch = .0499"
Angle from Center = 1.4287
#0 Morse taper is long and not the correct taper. It's large end is about the same size as the Bach small end.
#1 Morse taper is not the exact taper per inch. The small end is not small enough to reach to .355".
What you really need to see is dimensions as Bach has listed below in an old Mouthpiece manual.
Below is the Bach Fluegelhorn Standard Taper
Large end = .405"
Small end = .355"
Taper per inch = .0500"
Taper per mm = 1mm per 20mm
Taper per foot = .6000"
Angle from Center = 1.4321
Engagement = 1"
Go to a local Tool and Die shop and ask them to put a small Morse taper on a shank. What will you get? Probably a strange look or #0 Morse taper. Ok ask for a #1 Morse taper, will it fit in your horn…no. You need some specific dimensions.
Every taper needs a rate of Taper. Ask for a .0500” per 1.000”inch.
Every taper needs a starting dimension. Ask for .355” that is the small Bach
Then you need an engagement or length. That is 1.000”
The end diameter is .405” just as in the Bach drawing.