I need to make some sleeves for the 1st/2nd?/3rd valve tuning crooks to convert an old Hi Pitch horn to Low Pitch so it can be used conveniently. Thus I’d like to buy a foot or so (more than enough) of brass tubing, measuring .459 i.d. (I verified this by inserting the tuning crook into the tuning crook of my .459 Olds Ambassador—fit nicely, snug, but “just right”. I’ve done a search of general metals product companies, but don’t come up with anything closer than .472, which is too large. I also tried several old ‘beater’ horns I’ve got hanging around, but they were all too small, and I don’t want to cannibalize my Ambassador to do this. Enough horns have been (and continue to be) made with .459 bore that this product has to exist. Where can it be purchased? Any help would be appreciated.