There is a fantastic screw & bolt shop nearby.
I try to remember ask them on monday or tuesday.
They are less than 2km away from my place - so no biggie.
Before I go there - few facts
Thanks for the offer Nuuska, but maybe wait a bit with it. Well, sure you can check with them! But GAD is trying to get some from ebay (see the link in his post) which look almost right except the picture of the head looks a bit rough, but it might be just an example screw picture. See also the drawing above in post # 1 which is this type he will buy. He will do some research project with them vs. the original screws. Those 70ies/80ies HB-1 screws are so special they are extremely difficult to get anywhere. It almost looks like the original manufacturer is no longer around or something. Not sure if Hans might know who the screw manufacturer was. This might have been a totally unimportant detail back at the time. (It's almost like nobody found the original manufacturing location for the Franz pickups yet...At least not that I know. I even had a friend going to the local library in Woodside and the central Library in Jamaica (Queens) to check for the Fransch Electric Company in Woodside and the Franz company in Astoria or
Frank
Schulz, and they didn't find anything useful.... Not sure if Hans has more details by now.)
Absolute minimum length ?
The screws I am looking for are exactly as described in my post #1 and are US size screws.
1 1/8" size (which is about 29.5mm total length including head or about 28mm thread length).
The thread is not metric but #4-40 size threads which is a diameter of 2.845 mm. A M3 size screw does not fit.
I can't tell you if this was the original Guild size, that is however the size I have which came with one HB-1 but I don't know if the screws were original. GAD will find out. The other HB-1 came with #3-48 (2.515 mm diameter) screws which are too thin for the holes in the mounting flanges.
Can they be black - rostfrei - anything ?
Not black! The 90ies HB-1 had black Philipps head screws. The 70ies and 80ies screws are most probably steel as it looks (Not sure if stainless steel). Maybe they were chrome plated? The head almost looks like chrome. See picture. Right is the golden version, just to see how they head shape is.
Slothead - allen/hex - torx - etc?
Slothead.
Cylinder head?
No, not a cylinder head, they are called "pan head". A cylinder head is a completely parallel head on the side.
This pan head however is only about 1.5mm thick and has a diameter of about 5.4 mm (0.21")
But not like a Fillister head (pole piece screws), compare to the flat pan head. They are slightly round only on the edge of the upper side, but not on the bottom side.