FIGURE 11.

INDEX PLATE AND SECTOR.

First side- 24, 25, 28, 30, 34, 37, 38, 39, 41, 42, 43 holes.

Second side- 46, 47, 49, 51,53, 54, 57, 58, 59, 62, 66 holes.

(5)

The two following examples show how the index

plate is used to obtain any desired part of a whole spindle turn by plain

(a)

Using the rule given in paragraph 4c(3)(b)

above, divide 40 by 6, which equals 6 2/3 turns, or six full turns plus 2/3

of a turn on any circle whose number of holes is divisible by 3. Therefore,

six full turns of the crank plus 12 spaces on an 18-hole circle, or six full

turns plus 26 spaces on a 39-hole circle will produce the desired rotation

of the workpiece.

(b)

which equals 40/42 or 20/21 turns, 40 spaces on a 42-hole circle or 20

spaces on a 21-hole circle. To use the rule given, select a circle having a

number of holes divisible by the required fraction of a turn reduced to its

lowest terms.

The number of spaces between the holes gives the desired

fractional part of the whole

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