Schlage plug question

[Spinster]

I got a bunch of Schlage cores recently. I notice on many of them when I pull out the plug, there is row of dimples next to the pin holes. Anyone have an idea what their purpose is?
Thanks,
S

[selim]

I think it is for the lost ball method for constrution master keying. The cylinder has a few small balls in one,or two of the chambers.Then when construction is done,and the owners key is used those little balls get lost in the little holes next to the chambers.Then the constrution keys will no longer work. I think this is right,but may be wrong.

selim

[USApicker]

thats exactly right, selim. I made a thread on EZ asking about what they are for.

Correct selim.

Usually the construction keying balls we use are effectivly a 4 pin difference.

So the cuts on a 'Construction key' would be:
37592

And if the balls are in the second and fourth chamber, the Owner key would be:
33552

When the construction key is used, the balls are in the plug as the key is turned, but when the owner key is used, the pins are elevated above the shearline and when the plug rotates, these balls fall in the holes that are big enough for the balls, but not large enough for the top pins to get snagged on.


I think Gainsborough (TE2 keyway) have a similar system but they use smaller master pins\discs.

[Spinster]

All,
Thanks for the explanation.