Solid Plunger Firing Pins

[Austin W Hogan]

Richard; The end of the primer pin is very neatly rounded and smooth, and fits into a similar recess in the half inch long rod ( anvil?) that is hit by the hammer. There is no graininess associated with a break on either piece.
The compressed picture on the web does not really convey the radius, but if you look closely, you will see the ring around the pin where the anvil? was swaged on.

Best, Austin

[Austin W Hogan]

I soaked the firing pins in Ballistol for about an hour, wiped them clean and made a micro photo at .001 inch resolution in back satter, and .0005 inch resolution in forward scatter.

The dark field photo shows the smooth radius at the butt end of the pin. There is a radiused recess in the anvil .032 deep. It is also possible to see a short straight section intersecting the taper of the pin.

Also note the nickle plate on the undamaged anvil.

I am not sure that the web compression will retain this resolution.

This is a technique I am working to examine the appearance of a trout fly from beneath, lookin toward the sun, as a fish might see it.

Best, Austin

[Autumn Daze]

Austin, Fantastic photography! I find it almost hard to believe that Parker would use a two piece construction on the plungers vs. just turning up a one piece plunger and being done with it. Seems like a long way to go to get a short distance if ya know what I mean. I can't even begin to try and understand their logic on this one...

[Austin W Hogan]

Thanks Dave. I have a feeling that this is some how related to hardness. Look at a hammer gun, and the hammer is almost always deformed, but the anvil rarely is. That striking area must be deep and hard; a special case hardening was probably necessary to encase the anvil, without making it brittle. The anvil is 1/2 inch long and 5/16 diameter; the firing pin is 1/2 inch long, 3/16 at the joint and 1/8 where it hits the primer. Case hardening this as one piece would have left little ductile steel in the pin inself, resulting in early fracture and failure.
The real question is ; "how did Parker (King) join these parts". A weld might have nullified the hardening process; a swage would have been difficult considering the hardness of the anvil.

Best, Austin

[Autumn Daze]

Austin, Thanks for your insight.I would have thought that the factory would have just cased the whole piece. But subscribing to your school of thought and because these part's were made before the advent of true tool steel case hardening was the only avenue to toughen steel. If Parker case hardened the whole anvil it might not have been possible to draw back just the striker portion with any regularity with out creating a stress riser at the junction of the two diameters.

As far as the method to assemble these two pieces there is no easy answer. To try and swedge a soft pin to a hardened piece is not real feasible. The soft piece would have to be the part being worked and to keep it concentric after swaging would be a real trick especially in a recess as shallow as that. Pretty ingenious fellows to say the least.