Conventionally a combination lock is opened by
turning the dial two turns clockwise
to the first number of the combination,
which lines up the first notch then
counter-clockwise by one turn
to line up the next notch and then
clockwise and then the lock opens.
Now there's nothing that prevents you from
actually doing it the other way around.
You could turn the dial counter-clockwise
to line up the first notch,
and the clockwise to line up the second notch,
and counter-clockwise again for the third one.
The difference for this kind of combination though
is that you actually have to use a slightly different
set of numbers, because to line up the
last of the rotors, by turning
clockwise, we have to turn it to 18.
but counter-clockwise, the thickness of these littl
tabs in here actually have to be taken into
account so,
the counter-clockwise way of
aligning the rotor is actually a different number
so in this case it's 14 as oppossed to 18.
Simallarly for the next number,
which if I start counter-clockwise,
I have to do clockwise,
is also a slightly different number. Again to
compensate for the thickness of these tabs here.
So, on this lock, that happens to be 18,
whereas for starting with the clockwise turning,
it's actually 17.
For the last number, because it's structurally coupled,
it doesn't matter which way I turn, it's still
the same number, 11 in this case.
On an actual combination lock,
the left right left as oppossed to the right left right
combination is not quite so easy to work out
because we can't actually watch the rotors turn.
But using the wooden model as a guide,
we know that the first number is further to the right
and the second number is further to the left
when we start. So, for example, with this Master Lock,
the right left right combination is 15 17 31.
Whereas the left right left combination is 8 18 31,
as I've worked out partially through trial and error.
So, let me demonstrate. So, turn left
to 8,
one turn to the right and to 18.
And left again to 31.
And it opens.
Simarlily, the Dudley lock can also be opened
left right left, but...
the regular combination for this lock is
30 14 47.
But, going left right left on this lock,
I've worked it out to 44
10
47.
If you could just watch the internals of the lock
figuring out what the left right left combination
of the combination lock is would be trivial.
But of course on a real lock we can't actually watch
the insides of it so...
Working it out is partially deduction and partially
trial and error.
Though once you've figured out the left
right left combination for a particular lock,
any lock of the same make
is gonna have roughly the same relationship.
In general for locks such as
the Master Lock or this combination lock,
if you want to do the left right left combination,
the first number will be less by a few and the
next number will be larger by a few,
and the last number will be the same.
For a Dudley, because turning clockwise
actually is increasing numbers as oppossed to
decreasing numbers, it's the other way around.
So, on a Dudley lock, the left right left combination,
the first number will be larger by a few
and the second number will be smaller by a few
and the last number will, again, be identical.
Explaining how to derive the left right left combination
from the right left right combination is
a little bit more verbiage than I'll put into
this video. But, if you want to know more about this,
go to woodgears.ca/combolock.