8 Apr
2025
8 Apr
'25
6:32 p.m.
On Apr 8, 2025, at 12:06 PM, Tony Duell via cctalk
<cctalk(a)classiccmp.org> 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