Re: sax necks
To properly address a non-perfect fit on the neck, you should have the neck tenon expanded or contracted as needed to fit the receiver as perfectly as possible. There are tools for doing that (I'll have mine before too terribly long, I hope). Teflon tape is a quick fix if you were trying out a neck that was a little loose, but once you find the neck that is your double, you should have it modified. You will have to hand over your horn along with the neck for someone to do the job right. I suppose you could measure it and tell them to make it size "x", but I wouldn't personally guarantee the job as the receiver might not even be perfectly round.