I need to make up a lock screw for my trulock bros. side by side, as the threads are worn and stripped. Measuring the thread on the remainder of the screw, i get a diameter of 0.1695 inches and as far as my poor eyesight can tell, 36 threads per inch using a thread gauge. I want to buy a die to cut the threads.
But looking at the thread charts in my machinery's handbook, the only one i can see that comes close is no.8 UNF.
Would this be correct ? What threads systems were in use in the English gun trade about 1900 (which is roughly when i estimate the gun to have been made). Before i measured the thread i had B.A. threads in mind.
Were there specific gun threads ?
A No. 3 BA screw has a no,I always dimension of 0.162” and a thread pitch of 34.8 TPI. Based on your reported measurements, the No.3 seems the closest fit. An M4-.7 has a TPI of 36.3 but the nominal diameter is only 0.157”.
I hope this is found to be useful.
Dave
