A couple of basic questions

[scudo]

When a lock is in the locked position I can understand that the driver pins are held back as they hit the shear line, but what prevents the key pins from dropping in to the keyway?

And in the pic of the padlock below how would they insert the barrel and then prevent it from falling out of the padlock.

[huxleypig]

It is usually (pretty much always with pin tumblers) because the warding of the keyway prevents it. The pins hit the warding 'ledge'.

[innerpicked]

The keypins are shorter than the chambers in the plug, so it does not matter if they are in the plug. They hold the plug in with a pressed in brass pin that is ground off and sanded.

[flywheel]

1. Key pins rest on a ledge and at least the top third remain in the plug
2. The keyway is thinner than the key pin diameter. Therefore, when the holes are drilled through the plug's top they create channels in the plug wall that restrict all lateral movement of the pins. If only drilling partway, the channel stops short and the pins cannot fall any lower.

As for the plug question I'll venture a guess. The lock body starts as two pieces, the bulk and the lid (in this case the very bottom of the lock). After the internals are added the lid is welded into place and all marks are polished away.

Take it easy

[Oldfast]

Good question. Might be easier to just see, rather than try 'n explain.



Self-contained locks like these are not designed to be disassembled. The pins & springs are loaded
through holes in the edge of the lock body, then capped and finished off. If you were to grind or just
begin lightly sanding the edge of the body, you'll start to see the outline of these chambers.

.....how would they insert the barrel and then prevent it from falling out of the padlock.

So this is a 5-pin lock, but you see six chambers? The sixth chamber is for a retaining pin.
It's also spring loaded (but not always). It sets in the milled out groove around the core.
This allows the core to turn yet does not allow the core to be pulled out of the lock.