A long metric/imperial thread on the Australian Woodworking forum
included a discussion on the best way of marking a metric tape. The
fact the the marks at 5mm were slightly longer than the other 1mm
marks (but shorter than the 10mm marks) was considered a plus point.
I have just bought a Starrett 6"/150mm metric conbination square. I
was surprised to find that there are four heights of marking (longest
to shortest):
10mm, 5mm, (2,3,7,8)mm, (1,4,6,9)mm. Or, IOW, extra prominence is
given to the markings at 2,3,7,8 mm position within 10mm.
Anyone know why?
I have the feeling that they would have preferred to have marked 2.5
and 7.5, following imperial practice! Even odder, two of the four
edges have 1/2 mm as unit, so markings at 2.5 and 7.5 would have made
some sense there!
(and please, no wars. . .)
"Topaz" <[email protected]> wrote in message
news:[email protected]...
> A long metric/imperial thread on the Australian Woodworking forum
> included a discussion on the best way of marking a metric tape. The
> fact the the marks at 5mm were slightly longer than the other 1mm
> marks (but shorter than the 10mm marks) was considered a plus point.
> I have just bought a Starrett 6"/150mm metric conbination square. I
> was surprised to find that there are four heights of marking (longest
> to shortest):
> 10mm, 5mm, (2,3,7,8)mm, (1,4,6,9)mm. Or, IOW, extra prominence is
> given to the markings at 2,3,7,8 mm position within 10mm.
>
> Anyone know why?
> I have the feeling that they would have preferred to have marked 2.5
> and 7.5, following imperial practice! Even odder, two of the four
> edges have 1/2 mm as unit, so markings at 2.5 and 7.5 would have made
> some sense there!
> (and please, no wars. . .)
Sounds reasonable. It uses the exact same reasoning as making the 5mm mark
prominent. How else would you do it?
I don't consider this an "imperial vs. metric" issue. Really it is just a
way to subdivide something into 10 rather than 8 or 16. You would have the
same issue with 10'th of inches.
-j