Singer 20U screw size on bed

[Birdpath]

Hi folks: I know the Singer 20U is undersized for leather work. I am trying to set up a binder and need some help. The machine has the usual two holes in the bed for attaching binders. However, the usual knurled screws that some with binders are not the right size. They fit my other machines (e.g. Juki) but not my singer 20U. Does anyone know what screw/thread size these holes are tapped for? Many thanks for any help, Daniel 

[dikman]

You might be struggling to find screws to fit as Singer used their own proprietary thread sizes. It might be easier to re-tap the holes to more standard threads.

[CowboyBob]

@BirdpathThis screw is the standard attachment screw #286S 9/64"x40 tpi if you can't find ant we stock them.

[catskin]

I realize this is a different machine. But does the Singer 29U172A use standard or Singer screw to hold the needle in? 

I think both were made in Japan.