Need to know thread size for Guan Sheng tube rings

Post by **VinSnr** » Fri Jun 01, 2007 1:34 pm

Hi guys,

For you who own those China/Taiwanese scopes, do you know what is the thread size for the hole below their tube rings?

I bought a APM deluxe dovetail that has 1/4"-20 screws but they can't fit into the hole. The diameter of the hole seems the same, but the thread size is different.

any ideas?

mrngbss · Post by **mrngbss** » Fri Jun 01, 2007 2:34 pm

Have you tried 6mm size threads? 1/4" is about 6.3mm

Meng Lee · Post by **Meng Lee** » Fri Jun 01, 2007 2:54 pm

Its a finer thread than 1/4". I have a number of bolts for that, but I am not sure what is the thread size.

Post by **VinSnr** » Fri Jun 01, 2007 3:00 pm

Meng Lee wrote:Its a finer thread than 1/4". I have a number of bolts for that, but I am not sure what is the thread size.

I think the 6mm does fit. Is there anything else between 6mm and 1/4"?

Post by **rcj** » Fri Jun 01, 2007 3:56 pm

perhaps there might be a difference in the pitch of the hole even with the same 1/4" size? are you able to screw into the hole just a bit and not fully? have 1/4" size but different pitch screws...

mrngbss · Post by **mrngbss** » Fri Jun 01, 2007 4:53 pm

VinSnr wrote:
I think the 6mm does fit. Is there anything else between 6mm and 1/4"?

I asked before and the blur face on the shopowner tells me 'No'. But remus may be right, perhaps the pitch of the threads is different. I still think the manufacturer will not go to an extend of using special thread and pitch sizes. Wait till you get home and try out a 6mm screw.

Clifford60 · Post by **Clifford60** » Fri Jun 01, 2007 7:54 pm

If I remember correctly, imperial system and metric system uses different pitch angle, so the pitch distance will be different too.

Post by **perseid** » Sat Jun 02, 2007 12:39 am

GS tube ring uses metric system. The bolts that goes with it is know as M6. The APM uses imperial. If I want to get the APM bolts, I would tell the shopowner that I was 1/4" BS thread.