lock design question

[E-Mind]

If it were something like a cruxiform key, then it would work.

But that isn't how it is described, since the OP says "a tubular lock with ridges", and Shrub is right, it won't work.

Say you take a tube shaped key. You put it in the lock, and turn it. Once turned 45 degrees (with 8 pin stacks), the lock is locked again, only now the key is jammed in it. Since the pin stacks don't move with the key, it just isn't going to happen. And if they do, you are going to need seriously good tolerances to stop the whole thing being a little off-center, which would mean the key would jam again anyway!

If it isn't a tube shaped key, why have one? Go with the cruxiform or H shaped key, or whatever. Otherwise you have a long cylinder down the middle it makes no sense, because, although it turns, nothing else does.

ok - how about instead of turning the key - you push the plug inside the housing to a place where it can turn while keeping the key in its current position - i.e. by turning knob inside the key - which you push, then turn, once the key is inside the keyhole.

The key keeps all the pins in their right configuration allowing the plug to be pushed in.

The mechanism could be a net tube between the buttom and top pins - connected to the plug - so that all the pins need to be at the sheeline so the net can pass between the top and buttom pins without trapping.

Once the net was pushed all the way - the plug would be in a possition which it can now turn.

to combat the problem of the large keyhole - you can have each pin be only one of two hights - binary key.

This way you have 2 options to the power of 96 pins (pin inside each pin of 8 rows of 6 pins)
the number of combinations is - 79,228,162,514,264,337,593,543,950,336

I don't know how to pronounce that number.

[Shrub]

MrB,
I said it could be made to work but the keyway would be massively wide (in lock terms)

E-miand,
Yes that would get round a lot of problems but to have a hard wearing key you will have to have at least 2mm thickness in the outer sleve to take the pin cuts and then a tube on the inside at around 1.5-2mm thickness as this has to turn the plug so needs some strength, this is already a 3.5mm wide keyway!

[NKT]

If you made it so the entire plug moved inwards, as you describe it there, the easy way to beat the lock would be a hammer to the center column, which would wreck all the pins.

In fact, you could hammer a steel tube down it of the right size, which would depress correctly (on average) half the binary pins, then twist it with a spanner or whatever. 96 or 48 pins made of brass or even steel won't stop that sort of abuse.

Not picking it, but bypassing it. End result is the same.