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
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. . .)