I need help in identifing a set of screws. I have an under rib and thimbles for a T/C Renegade that I purchased with the screws. I want to attach it to a Douglas barrel and I need to purchase taps and drills for the screws. I think that they are 6 X 48, but my thread gauge only has a 40 TPI. The thread is finer than 40TPI. I have not been able to find any place that gives the major diameter of #6 screws. I think if I can be sure that the screws are #6, and I know the thread is finer than 40TPI they must be 6 X 48.

I need help in identifing a set of screws. I have an under rib and thimbles for a T/C Renegade that I purchased with the screws. I want to attach it to a Douglas barrel and I need to purchase taps and drills for the screws. I think that they are 6 X 48, but my thread gauge only has a 40 TPI. The thread is finer than 40TPI. I have not been able to find any place that gives the major diameter of #6 screws. I think if I can be sure that the screws are #6, and I know the thread is finer than 40TPI they must be 6 X 48.
You could call T/C. and ask a tech guy.

Major diameter of a # 6 thread is .138

Thank you all for the information.

usually you can stop in at a machine shop and they can tell you pdq what the thread pitch is