and then subtracting as before we get the required diameters
Example 4.Let the conditions be as in the preceding example, the cone pulley having, however, three steps instead of five, the largest diameter will then equal 8 in.; and by dropping the end differences and subtracting
we get the diameters 8 in., 6.04, and 4 in., which correspond respectively to 2nd, 3rd, and 4th steps of the table, and to the 1st, 2nd, and 3rd steps of the three-step cone.
Example 5.Let the distance apart of the centres be 60 in., the average difference between the adjacent steps be 21⁄8in., the smallest step 7 in. and the number of steps = 5. The largest step will then be 7 in. + (4 × 21⁄8) = 151⁄2inches.
Now an inspection ofTable II.will show that it contains no horizontal lines corresponding to the average difference 21⁄8inches, we cannot, therefore, as heretofore, obtain the required differences directly, but must interpolate as follows: since 21⁄8inches is quarter way between 2 inches and 21⁄2inches, the numbers corresponding to 21⁄8inches (for any given distance apart of the centres), will be quarter way between the numbers of the table corresponding to 2 inches and 21⁄2inches. Thus, inTable II., we have under 60 inches,
Dividing these differences by 4, we get:
to which we add,
and get for the differences corresponding to 21⁄8inches
and subtracting as before,