Herters 44 single action revolver rear sight elevation screw needed

[Daver7]

I have this Herters revolver and I need a rear sight elevation screw.
I've tried Brownells, they asked me to check with
http://www.homesteadparts.com/shop/
and
https://gun-parts.com/singleactions/
I'm not seeing anything outhouse sights.
Does anyone have a idea where I could find a replacement?

The gun was made by Sauer and Sons in 1966 and I'm not sure if the machine screws are metric or imperial. The threads are either 40 tpi imperial or 0.6 metric.
The minor diameter is .114 or 2.895 millimeter. that puts in the M3.5 x 0.6 range.

[Der Gebirgsjager]

If worse comes to worse and you can't find the proper screw, you can probably drill and tap for something slightly larger in a common thread.

[Bmi48219]

Try Jack First. I needed an ejector for a Herters 357. They had one for a Hawes that matched. In the 60’s Sauer & Sons made the Hawes line also.
You may also find part listed under Hawes manufacturer on gun parts website. If they have the schematic that will help. Some Hawes didn’t have adjustable sights.