On Wed, 21 Jul 2004 00:51:53 +0000, DoN. Nichols wrote:


Now -- if you are planning to use this in the shop, I should
perhaps point out some limitations:

1) A slide rule can't add. It multiplies, divides, squares and
square roots, logs, trig functions, and exponentials, but not any good
for adding.

Bummer. BTW, I seem to remember reading somewhere that at chip level
(digital computers) division & multiplication are easy to implement,
contrary to addition & substraction.

2) A slide rule is of limited accuracy. For the most part, you
should not expect to get more than three significant figures out of it --
though this varies somewhat with where on the scale you wind up, as
things are spread way out at the low end of the scale, and scrunched up
at the high end. If you are working in inches, say 1.25", you won't be
able to calculate anything to 0.001" (where you are machining).

If you want more significant figures, you need a longer scale. 20" is not
enough for machine shop work. Big circular slide rules squeeze a bit
more scale length in a given maximum dimension, but still is not
adequate. A big cylindrical slide rule might work -- but it would be
awkward to use.

The slide rule was *great* in circuit design, as the components
were usually not made to a precision as great as the slipstick could
deliver. I would never consider it to be the best choice for machining.

Mmm. Had no idea. What they did use in the machine shops of old?



P.S. I also almost got arrested because of one. I was wearing it on
my belt, and a policeman thought that it was a knife. :-)

LOL. I keep a Leatherman Wave and a Maglite in my belt. I often get the
suspicious look from security people
--

Regards,


Mongke