[Phono-L] Part for Columbia Graphophone (MacDonald) Model AB

[bruce78rpm at comcast.net]

I was at a MOCAPS meeting last Sunday and one of the members dsiplayed and demonstrated the unusual model AB (MacDonald) Graphophone, I noticed that it had a shallow flat headed screw with a decorative head that actually holds the 5" telescoping Mandrel in place once it is placed over the regular mandrel. I have a Columbia AB and never realized that feature existed until I saw this AB. So I am presently looking for an original holding screw, which I wouldn't hold out much chance of finding or a good reproduction if need be. Does anyone know if there is any suppliers who make a good repro holding screw for the 5" Telescoping Mandrel for the AB? 

Thanks for your help in advance, 

Bruce