TM 9-243
READING THE SCALE OF A RULE OR TAPE - Continued
Now turn the rule and look at the edge with a 16 marked
on it.
To determine the number of 32nds in 5/8, remember
four divisions or 4/32 are equal to 1/8 inch. If 1/8 is equal
to 4/32, then 5/8 is equal to 20/32 as shown:
If 1/8 = 4/32, then 5/8 = 20/32
(4 x 5 = 20)
There are now 16 equal divisions between each inch.
Since 2/16 reduces to 1/8, divide each 1/8 into two equal
parts producing 1/16, 3/16, 5/16, 7/16, 9/16, 11/16,
13/16, and 15/16.
Common tapes and rules usually are not graduated
smaller than sixteenths. However, precision measure-
ments require smaller graduations.
1.
Find the 20/32 reading on the scale as shown
above.
2.
Write the new fraction 2-20/32 inches.
Finally, look at the edge marked 64. Each inch is now
divided into 64 equal parts.
Look at the back of the machinist’s rule. Find the edge
marked 32 and once again look between the numbers
“2” and “3.”
To read this rule, remember:
1.
Sixteen divisions (16/32) are equal to 1/2 inch.
2.
Eight divisions (8/32) are equal to 1/4 inch.
3.
Four divisions (4/32) are equal to 1/8 inch.
4.
Two divisions (2/32) are equal to 1/16 inch.
To read 2-5/8 inches on the scale, first find the two inch
mark, then determine the number of 32nds in 5/8.
To read this rule, remember:
1.
Thirty-two divisions (32/64) are equal to 1/2 inch.
2.
Sixteen divisions (16/64) are equal to 1/4 inch.
3.
Eight divisions (8/64) are equal to 1/8 inch.
4.
Four divisions (4/64) are equal to 1/16 inch.
5.
Two divisions (2/64) are equal to 1/32 inch.
To read 2-3/4 inches on this scale, first find the two inch
mark. Next, determine the number of 64ths in 3/4.
3-2
