> On Apr 8, 2025, at 12:06 PM, Tony Duell via cctalk <[email protected]>
> wrote:
>
> ...
> I think there is only one key. The lock is somewhat unsual though.
>
> There are 4 pins in the plug (the rotating part). There are 3
> positions of the lock and the key is removeable in all 3. There are
> therefore 3 sets of upper pins and springs in the housing. The 3
> positions are 'OFF' (anticlockwise), ON (centre), PM (clockwise). The
> visible holes in the housing were always empty, I've not removed
> anything there. I think they were there to allow the springs and upper
> pins to be inserted when the lock to be assembled. Note that the hole
> for the 'OFF' position are ofset away from the front of the lock.
>
> Here's what I think happens. In the ON position you can use the key
> and simply turn to PM. And go back again But to select OFF you have
> to push the key and plug inwards before turning the key. To turn on,
> you just turn the key (you can't go too far and select PM by
> accident), the plug will then spring forwards. There was a compression
> spring in the back of the lock, forcing the plug forwards. I have
> removed this now for the moment.
>
> The in/out motion of the plug is controlled by a pin (the end of which
> is the silver circle in the 'side' photo) running in a groove in the
> plug.
That all makes sense. To allow removal of the key there have to be holes at
that position to let the pins (the ones in the cylinder) move upward as the key
is extracted. Then normally the pins in the lock body would be pushed inward
by the springs, locking the cylinder.
If for some of the positions you have holes but they are empty, it means the
key can be removed in that position, and then the pins would probably drop back
into the cylinder, leaving it unlocked and free to turn. But in addition, you
could turn the lock upside down and let the pins slide out (be sure to keep
them in order). The lengths of those pins would tell you the cuts needed for
the key.
paul
