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A220000
Sixty fourths of an inch in thousandths, rounded to nearest integer.
0
16, 31, 47, 63, 78, 94, 109, 125, 141, 156, 172, 188, 203, 219, 234, 250, 266, 281, 297, 313, 328, 344, 359, 375, 391, 406, 422, 438, 453, 469, 484, 500, 516, 531, 547, 563, 578, 594, 609, 625, 641, 656, 672, 688, 703, 719, 734, 750, 766, 781
OFFSET
1,1
COMMENTS
Diameter of successive drill bits, in thousandths of an inch, within an ordered set consisting of increments of 1/64th of an inch. Traditionally the sizes of bits in such a set are expressed in simplest reduced fractional inch values: 1/64, 1/32, 3/64, 1/16, etc. Of fundamental importance to machinists, tool and die makers, carpenters, hobbyists, insomnial science teachers, etc.
REFERENCES
Jack Erjavec, Automotive Technology, 2010, pages 66-73.
Frank D. Graham, Audels Machinists and Tool Makers Handy Book, 1941, pages 34-48.
IBM Corp., Precision Measurement in the Metal Working Industry, 1939, page 11.
FORMULA
a(n) = round(125*n/8), with 0.5 rounded up.
EXAMPLE
For n = 5 the a(5) term = (5/64)*1000 = 78.125, which is rounded to 78.
MATHEMATICA
Table[Floor[1000 n/64+1/2], {n, 64}] (* Harvey P. Dale, Jan 13 2020 *)
PROG
(PARI) a(n)=(125*n+4)\8 \\ Charles R Greathouse IV, Dec 06 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Marc Alan Rosner, Dec 03 2012
STATUS
approved