I believe that some of the Philly Sterlingworths had the recessed hinge pin also, Gary

Right Gary, the very early ones.

Incidentally, Congratulations on your recent induction to the Parker Foundation Hall of Fame. It is very well deserved.

Thanks Dean, It was honor to be chosen, a humbling experience! gary

King's Parent that included the recessed hinge-pin feature had run its course when Ansley H. Fox used it on his Fox Gun Co., Balto., MD., U.S.A. guns in 1898 and 99 --

http://img.photobucket.com/albums/v3...Overall153.jpg

and the Philadelphia Arms Co. Fox doubles 1902-06 --

http://img.photobucket.com/albums/v3...o/262EDM01.jpg

The recessed hinge-pin Sterlingworths were 1910 --

http://img.photobucket.com/albums/v3...psf2599456.jpg

to 1913 --

http://img.photobucket.com/albums/v3...torPinGun2.jpg

Some of those early Lefever hammer guns with the recessed hinge-pins might have infringed a bit!! Or, maybe they are where King got the idea!!

I believe my gh 59374 made in 1890 has recessed hinge pin. It is also the single piece pin. Pics in general forum.

non recessed hinge pin
 

The latest gun in my collection that has the non recessed hinge pin is serial # 5598 only two numbers away from 6000 , it also has plain steel barrels notice the color in protected places, compared to the rest of the barrels

non recessed hinge pin
 

two more,

Gary, is that an S between the upper and lower crescents?

Whatever is stamped there, is the barrel steel designation stamp.

Gary, please show the other side of the frame.
A lot of folks don't know that the hole in the frame for the hinge pin is notched and the pin has a tab that fits in the notch to prevent the pin from rotating.

recessed hinge pin
 

Dean, yes it is s in the crescents, I have enclosed a photo that shows it well also one of the other side of the frame, If you need more I have about 30 pictures of this gun, Gary

recessed hinge pin
 

one more