Thread pitch of Redfield aperature screw in sight disks?

[JWFilips]

Hi Folks Like it says:
Anyone know the true thread pitch on the Redfield screw in aperture sight disks?

[fouronesix]

I think Redfield, Lyman and Williams all use the most common which is 7/32x40.
Marbles are 10x32 and Skinners are 12x40.

[Frank46]

Redfields and Lyman are 7/32x40 but since you didn't say which one you mentioned, some of their high end target sights did have a larger one which required an adaptor screwed in so as to use the discs with the 7/32x40 thread. Have an international setup that way. Frank

[JWFilips]

I have the standard Redfield disks. All of mine interchange with my sights. I recently picked iup a 1" disk which I would love to use on my GEW 98 however screwed in all the way, the bolt just kisses it and won't open by only about 2 mm.
The disks threaded shaft is long and only threaded half it's length. I was thinking if I could thread it a bit more and shorten a bit I could fit it in the sight and have the bolt open I would like that

[fouronesix]

I see what you are trying to do- makes sense. Measure the diameter of the Redfield threaded shank. That will tell you if it is 7/32x40 and it will tell if you need to open up the non-threaded portion of the sight. If so then get the correct bit and open up the non-threaded portion. If not then just get a 7/32x40 tap and thread the non-threaded portion.

If the non-threaded portion is not drilled to correct size for the 7/32 tap- running a tap in could distort or crack the sight.