Identifying a firing pin

[Peter Laidler]

Further to BinO's thread 10. This close thread form is to make sure that the cocking piece is a tight fit on the striker. If it ain't then you really can wave goodbye to any notion of a good pull-off. The EMER says that in order to make it a tight fit or tighten up the fit you can strike the thread on the striker with a small letter 'S' on each side!!!!! I don't go along with that - although I have done it of course. Just clean up both threads and tin them. It'll be tight enough for a good tight fit, ain't going to work loose and you'll be able to get it apart in the future without snapping the ears off the TOOL, removing, striker

[Mk VII]

As to telling the difference .. carry a 1/4 BSF nut with you to test with - or a cocking piece of known origin.

[Bruce_in_Oz]

And another thing..

The REAL engagement is between the parallel "seat" in the front part of the cocking piece and the smooth, parallel tail-end of the striker.

The mating of these surfaces keeps things lined up and "rigid"; the thread stops it coming apart..

Dimensions and tolerances for the No1 components:

Striker "parallel":

0.25" Accept
0.249" REJECT

That's it; a 1 thousandths of an inch tolerance.

Cocking piece "parallel" bore:

0.25" Accept.
0.251" REJECT

Not exactly a "racing" fit!

Given the machinery and metrology of the times, I wonder how many components it took to get these sorts of dimensions correct?
.

[Peter Laidler]

Yep...... I hadn't taken notice of that either Bruce, It is the parallel shank and hole in the c/p that keep it all aligned! Which makes me wonder why you still find bent strikers when you test them! Oh yes...., just thought..... Some people bend them to get the two-stage pull off as an alternative to stining the bents correctly. Thanks Bruce