Need help with a fly.

[Rolf]

I can’t get the fly to clear the half cock notch when cocking the hammer.
The sear gets stuck on the tip of the fly. This stops the fly from rotating rearward and clearing the half cock notch.


When going to the full cock notch, the fly moves forward and clears the full cock notch as it should.


When releasing the hammer, the fly keeps the sear out of the half cock notch perfectly.


How do I get the fly to move to the rear and clear the half cock notch?
If I push the fly to the rear, the sear engages the half cock notch as it should.

I’ve tried polishing the fly and sear.  Does not make any difference.
This is the fifth fly I have made for this lock and it’s driving me nuts.
I am making six locks. The flies I made for the three first locks work as they should. I don’t understand what’s wrong with this lock.

Best regards
Rolf

[Jim Kibler]

The issue appears to be the angle of the sear / fly contact surface and how they relate to each other.  The way this lock is designed, the force from the sear basically pushes straight along the fly axis.  That is there isn't any rearward or rotational force.

Jim

[Bob Roller]

Make the radius tighter in the area forward of the "V"cut for the fly.What I see is the sear spring exerting pressure that seats the forward tip of the sear exactly on the pointed end of the fly and making the area of the tumbler a bit tighter should allow the sear to move the fly back during the cocking cycle.
Bob Roller

[Rolf]

Thank you for your advice, Bob and Jim. It worked like a charm. I filed away the portion of the thumber marked with red and now the fly functions perfect.
Two more locks to go. Hope to post a chapter on the fly at the end of june.

Best regards
Rolf

[Bob Roller]

BINGO!! It works.I think I made about 40 of these full size match rifle locks and maybe 10 for rook rifles or pistols.
Your fitting of the tumbler support shaft thru the bridle is beyond perfect so keep us all in the "loop" during this project.
I have a semi finished "rook"lock here.Part of it's here in the house and the rest is in the shop.Maybe someday......maybe,
Bob Roller