Pedersoli lock quality

[Zonie]

I don't think Pedersoli ever made a lock (or any other gun part) that had UN (Unified National, measured in #'s or inches) threads.

They are in Italy and all of their threads are Metric.

If your lock has UN threads, someone has been frinkling with it.

 

[user 28522]

Well I would normally agree except for the 5/16 x 24 barrel (drum vent threads). There is no question that the lock bolts in the cap lock are 8-32 so I am at a loss.
I'll have to wait till after the weekend to hear back from DGW but the initial response was that the lock screws they had (8-32) didn't fit the lock they sent me. The Flint lock from DGW (Pedersoli) definitely had a different thread.

Longone

 

[Zonie]

First, let me point out that the "5/16-24" vent liner is not a 5/16-24 thread.
It is a M8 X 1 thread.

A male 5/16-24 thread has a major diameter of .3125" maximum. The distance between the threads is .0417".
The male M8 X 1.0 thread has a major diameter of .3152" maximum. The distance between the threads is .0394".
The slight increase in the 8mm metric thread diameter will allow short lengths of the different thread pitch on the 24 thread per inch UN thread to screw into the hole.
This is not a good idea for threads that are subjected to high pressures like nipples or vent plugs but folks do it.
I strongly suggest using the correct M8 X 1.0mm nipple or vent liner.

The #8-32 thread has a major diameter of .164" and a thread pitch of .03125".

A similar metric thread is the M4 X 0.7mm, a commonly used thread size.

The M4 X 0.7 thread has a major diameter of .1576" with a thread pitch of .0276".

In this case, the smaller major diameter of the M4 metric thread will tend to interfere with a #8 screw major diameter. The smaller metric size is also intolerant of the differences in the #8-32 threads pitch making it almost impossible to screw the UN thread into it.