Hi bent,
I definitely appreciate several of the links that you have posted.
And, I appreciate the idea that fractions and decimals are just
different ways to represent the same measures. Many people see a
decimal representation like 0.015" and immediately think "that's an
absurd tolerance for woodworking" but if they see 1/64" they say
"that's appropriate for woodworking". In the angular example cited, I
think that everyone will admit that 1/3 of a degree is significant for
good joinery but when it's represented in terms of minutes of arc then
suddenly people think it's absurd. Your point is well made and the
allusion to the body parts of a king drives it all the way home.
I especially like your last point where you demonstrate the joys of
doing fractional math. There are times when working in decimals is
preferable!
However, I do believe that plastics which come in thicknesses below
0.006" (6 mil) have very practical and valid uses. ;-)
Thanks,
Ed Bennett
http://www.ts-aligner.com
bent wrote:
a meter is a meter. an inch is an inch. micro is a millionth;, theres one
million micrometers or microns in a meter. nothing to do with a .001", a
thousandth of an inch, or the imperial system. A thousandth of an ich is
for those who don't think a 64th or 128th is really a good way to divide an
inch. Its still the same inch in the first place. Just because its been
divided by ten, then that can be divided by ten, etc.does mean it has
anything to do with the metric system, micrometers or microns, which are
just that long, but historically have been divided by 10, 10, 10 etc. Each
time you divide by ten you just write down another digit, you don't need to
track down a king for a new body part.
a mil is the same thing as a 1000th of an inch .(001"). When you buy
plastic you buy 6 mil plastic, it is 6 thousandths of an inch thick. mil as
in milli, or thousandth, not million, not meteric. btw 4 mil plastic is
really thin, don't use it. If you can rip it apart its probly not to code.
A 64th of an inch is 1/64" = .015625; which is
no tenths of an inch
1 hundredths of an inch
5 thousandths of an inch
6 ten thousandths of an inch
2 hundred thousands of an inch
5 millionths of an inch
What is: most of 2 inches & 33/64ths thick subtract a half inch (well about
2/3 of a 16th less than that), shifted the majority of 7/16 to the right,
and accounting for moiture content, and alowing for the thickness of five
layers of paint on a tape measure? If I know it has to be tight to within
say 3/128"; or say at exactly the point, but projected at 90 dergrees 4
inches away at thatis point, plus or minus 1/128", bu t when that
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