I'm swapping the bell on my Franken F.

I have a Olds A-20 f-section, mounting to a King 606 bell.

The gap between the F-section and the bell shank is too tight for the (non-original) brace / spacer that was on the donor.

I need ones around 6.5 mm and 5.5 mm high.

The two tubes being braced are 15mm and 23mm OD.

I'm not a shop, so I can't go refer to the Allied catalog.

My options are:

1) Find something that fits from Conn-Selmer. Problem is they just list application, not dimensions.

2) Fabricate something. Problem: I don't have brazing equipment - I'd have to soft solder it.

3) Maybe someone here has something in their junk bin?

Hoping someone can help me on any one of the options above.

A reference image: