LOTABLE

To Calculate the Pitch of a Toothed Wheel, when the radius and number of teeth are given; and the RADIUS, when the pitch and number of teeth are given, from 10 to 159 teeth...

RULE 1. Divide the required radius by the radius opposite the given number of teeth in the table

required pitch of the wheel.

the quotient will be the

Example. To find the pitch of a wheel whose radius is 43 inches, that shall contain 90 teeth:

Required radius 43 ÷ 14·327 = 3-inch pitch.

RULE 2.-Multiply the radius opposite the given number of

teeth in the table, by the pitch required; the product will be the required radius of the wheel, tool a

Example. To find the radius of a wheel that shall contain 48 teeth of 24-inch pitch:

In the Table, radius 7·645 × 2·5 = 19 inches nearly.

For finding the Strain that may safely be applied to a good Hempen

Cable.

To ascertain the Strength of Cables.-Multiply the square of the circumference in inches by 120, and the product is the weight the cable will bear in pounds, with safety.

To ascertain the Strength of Ropes.-Multiply the square of the circumference in inches by 200, and it gives the weight the rope will bear in pounds, with safety.

To ascertain the Weight of Manilla Ropes and Hawsers. Multiply the square of the circumference in inches by 03, and the product is the weight in pounds of a foot in length.

This is but an approximation, sufficiently correct for many purposes.

TABLE

Showing the Size of Cables and Anchors proportional to the Tonnage

of Vessels.

TABLE

For finding the Strain that may be applied to a Hempen Rope with

Of Weight of Copper Rods or Bolts, from 1 to 4 inches in diameter,

and 1 foot in length.

Weight of a copper rod 12 inches long and 1 in. diameter = 3:039 lbs.

lbs.

Weight of a brass rod 12 inches long and 1 inch diameter = 2.86

Of the Weight of Riveted Copper Pipes, from 5 to 30 inches in diameter, from 3 to 5 thick, and 1 foot in length.

The above weights include the laps on the sheets for riveting and caulking.

IT

The weights of the rivets are not added; the number per linear foot of pipe depends upon the distance they are placed apart, and their size upon the diameter of the pipe.