25 Apr
2011
25 Apr
'11
4:21 p.m.
From: Pete Turnbull: Monday, April 25, 2011 5:44 AM
Yep. Though the later characterizations in mm and mils are correct.
Looking down
the barrel of the key with the tab in the 12:00 position,
and reading clockwise, I measure approximately 0.8", 0.0", 0.11",
0.44",
0.11", 0.8", and 0.11".
You've apparently misplaced the decimal point :-) A 0.8" cut, which is
over 3/4", would be longer than the key's tube... > Actually, rechecking this with the 10x magnifier
and reticle (more
> accurate) gives right at 1mm, 2mm, and 2.6mm for the 3 depths
> of cut. (That's 39, 79, and 102 mils).
Rechecking the cut that I thought was zero depth with the magnifier,
I do see a 10 mil nick there, so you are correct -- there are no zero
depth cuts. (That 10 mil cut is nearly invisible in the corrosion of the
key I was measuring. which still works :-).)
Here's what I got from two original XX2247 keys:
tube OD 0.377" (9.58mm), tube ID 0.310" (7.87mm).
Cool. I hadn't thought to measure those.
These are actual measurements from a depth micrometer.
As you can see if
you do the conversions, it's not easy to get consistent results; the ends
of the keys aren't perfectly flat.
I like the magnifier and reticle for that, as it makes it possible to sort
of
"visually smooth" the vagaries of the actual surfaces.
I'm not quite sure what this says about cutting
tolerances or what
multiple the depths of cut are.
I wondered about the tolerances, too. Seems like they can't be super
tight, or the keys would be more difficult to use than they are. Would
be nice if someone could look up somewhere what the spec's were/are.
Vince