Kevin,
Using dividers is fine ASSUMING ONE CAN DO THE ASSOCIATED MATH. My experience with newbies and not a few so-called professional machinists is that most of them can not do even the simplest mathematical computations. For many, computing the chord length for a given number of holes might as well be calculus.
I've had numerous Luddites make comments similar to yours. So many, in fact, that I took the time to write some thoughts on the subject - see below. If we abandon the use of the computer, should we also abandon CAD programs and return to the drafting board?
Remember, one of the goals of this forum is to help folks who want to build engines. Anything that makes things easier for them is worth discussing here.
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WHY WRITE A PROGRAM ?
I've been asked on many occasions why I would bother to write a
program that does little more than provide information readily available in
certain reference texts. My answer is, "Why would one buy a scientific
calculator if one already has a book with a table of trig functions in it?"
GAGE is a good example. It allows you to find (sheet/wire) gage
number given thickness/diameter or vice versa. This is information easily
available in 'Machinery's Handbook' or a wealth of other references. Why
write such a program?
AVAILABILITY
First, not everyone has the needed reference work to hand or
necessarily knows instantly which book to pull from the shelf. Even if one
has the book, finding the information can often be tedious. In the
information age, it's generally easier to find data via the web than to search
for it in one's (even perhaps extensive) home library. If the information is
stored on your computer, you're always within a few keypresses of having it to
hand. In fact, the ready availability and locatability of information is, in
my mind, a more important asset of the computer than it's ability to do
lightning fast computation.
CONVENIENCE
If you're a regular computer user, as many of us are today, you
already know that typing some simple command, like 'GAGE' is far easier than
searching out the book, scanning the index, finding the page, reading the
table usage information, and then interpolating to find the desired
information. Where appropriate, my programs tabulate output into a file which
can be printed and carried to the shop for reference and that's a lot easier
than dragging a bulky book to the shop and trying to hold it open with your
anvil as a book weight.
SPEED
What computers are all about. Being able to get an answer rapidly
makes you are more likely to 'do it right the first time' and to explore
alternate solutions to the problem. Often a well written program will
effortlessly provide 'more information than you asked for' and that can be a
boon to creativity.
ERROR MINIMIZATION AND LONG TERM MEMORY
If the code is written correctly, a program 'remembers' FOREVER EXACTLY
how to solve a given problem. The human mind is never capable of this long
term precision. Beyond remembering the mechanization of solution, it can also
remember all the likely errors to check for, catch typos, and just generally
formalize the input to the point where most simplistic errors will be caught.
ADAPTABILITY
By utilizing an easily edited data file as input, the well-written
program provides a means whereby the user can tailor the program, or add to its
data base without the need to understand in detail the interior workings of the
algorithm.