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# Converting to Decimals

(2003)How many decimal places for microinches. How many decimal places for millionth's(How to write 200 millionth's).

Steve Dutton- Muskegon, Michigan

*First of two simultaneous responses* (2003)

Platers have their own lingo for such measurements. We refer to plating thickness as "tenths" which are actually ten-thousandths of an inch. That is 0.0001 inch is called "one tenth" by platers. The term "tenth" actually refers to one-tenth of a mil with a mil being 1/1000".

Now to answer your specific question, a millionth of an inch is the same as 1 microinch. One hundred microinches is one tenth to a plater, thus, one millionth of an inch or a microinch is written 0.000001". With so many zeroes, you can see why saying one microinch is easier!

200 microinches = 2 tenths = 0.000200 inch

Syracuse, New York

*Second of two simultaneous responses *(2003)

Millionths of an inch and microinches are the same thing. The first digit after a decimal point is tenths, then hundredths, then thousandths, then ten thousandths, then hundredthousandths, then millionths. So 1 microinch would be 0.000001" and 200 microinches would be 0.000200" which is the same thing as 'two ten-thousandths of an inch' or 'point 2 mils'.

Ted Mooney, P.E. RET

finishing.com

Pine Beach, New Jersey