On Wed, Apr 9, 2025 at 3:22 AM The Doctor via cctalk
<cctalk(a)classiccmp.org> wrote:
Before I saw the photographs I would have guessed that
the three sets of tumbler
stacks would all be pinned identically. In terms of manufacture and maintenance it
would be both easiest and cost effective. But.
Photograph number five on that gallery page (nice and simple - I like it) makes me
wonder. To have a key that would work with all three sets of tumblers it seems
like it would have to have five cuts on it, not four. The four cuts closest to
No, I thnk it's just 4 cuts. I am pretty sure I can make out 4, and only 4 pins.
In each of the 3 positions those line up with the appropriate 4 upper
pins. The plug moves back for the anticlockwise position.
I must admit I had the same thought initially of 2 key types but I
can't see how that would work.
the shoulder would work in the (looking at the lock
straight on from the front)
rightmost and top positions. There should be room in the keyway for the unused fifth
cut at the end of the key, with no pin stack to engage. However, the leftmost
pinstack is offset backward by a distance of one pin stack, which implies that it is
pinned for the second, third, fourth, and postulated fifth cuts on the matching key.
It would make sense to find key blanks that almost but not quite fit - with a blade
of the right width and height but ideally without any of the warding grooves on the
sides (but that may not be feasible). Then grind out wards that match the weird
parts of the keyway.
But that might not be practical, either. Using a 3d printer to fab a couple of key
blanks wouldn't be a good idea, I think. I don't think plastic would hold up
well.
It wouldn't (and in my limited experience 3D printed plastic parts are
weaker than plastic parts machines from solid anyway). It takes
considerable torque to turn the camshaft in certain positions.
Would it be feasible to cut a couple of key blanks out of metal plate? Maybe metal
strips?
Should be possible to mill them, but as I said I'd want to make
several identical ones which is a pain without CNC tools (my
lathe/mill are entirely manual). I can't believe it's a custom keyway
so blanks should exist for it.
-tony