# Useful Information

## Other useful information

To find the circumference of a circle, multiply the diameter

by 3.14.

To find the diameter of a circle, multiply the circumference

by .318.

To find the area of a circle, multiply the square of the diameter

by .785.

The radius of a circle x 6.283185 = the circumference.

The square of the circumference of a circle x .7958 = the area.

Half the circumference of a circle x half its diameter = the area.

The circumference of a circle x .159155 = the radius.

The square root of the area of a circle x .56419 = the radius.

The square root of the area of a circle x 1.12838 = the diameter.

To find the diameter of a circle equal in area to a given square,

multiply a side of the square by 1.12838.

To find the side of a square equal in area to a given circle, multiply the diameter by 8862.

To find the side of a square inscribed in a circle, multiply the diameter by .7071.

To find the area of the surface of a ball (sphere), multiply the square of the diameter by 3.1416.

To find the volume of a ball (sphere), multiply the cube of the diameter by .5236.

Doubling the diameter of a pipe increase its capacity four times.

To find the pressure in pounds per square inch at the base of a column of water, multiply

the height of the column in feet by .433.

A gallon of water (U.S. Standard) weights 8.336 pounds and contains 231 cubic inches.

A cubic foot of water contains 7 ½ gallons, 1728 cubic inches and weighs 62.425 pounds at a

temperature of about 39°F.

## Bearing terms

**A.B.E.C. 1-3-5-7-9:** Annular Bearing Engineering Committee grades concern precision tolerances and geometry of bearings. Higher number indicates higher precision.

**A.F.B.M.A.:** The Anti-Friction Bearing Manufacturers Association. Incorporated. They have set up standards for the bearing industry.

**Adapter:** An accessory for holding bearing to shaft. Standard taper is 1” on the diameter for each 12” length.

**Average life:** Five times minimum life.

**B-10 Life:** Minimum life that is expected of 90% of a group of bearings under identical operating conditions.

**Boundary Dimensions:** Dimensions for bore, outside diameter, and width.

**Brinell:** True_Identations in the races or on rolling elements caused by sharp blows (metal flow).

**False – Wearing away of metal in raceways.** It is caused by rolling elements – sliding back and forth on race while bearing is stationary. Vibration causes this sliding movement.

**Cage:** A ring with the necessary number of pockets to equally space rolling elements. Also called Separator-Retainer and Spacer.

**Clearance:** Radial clearance – The amount of movement of the outer race at right angles to the shaft axis when the inner is clamped. Also called Internal Radial Clearance – Internal Clearance and Diametrical Clearance.

**Axis:** Clearance-Total movement parallel to bearing axis when an axial load is applied in first one direction and then the other. Also called End Shake and Axial Play.

**Conrad:** Standard single row deep groove ball bearing. No filling slots and no counterbore.

**Contact Seal:** A closure that connects inner ring and outer ring with rubbing contact.

**Counterbore Assembly:** Portion of one race shoulder turned and ground away to facilitate assembly with a greater number of balls.

**Cone:** Tapered bearing inner ring.

**Cup:** Tapered bearing outer ring.

**Super Precision Bearings:** Bearings with faces ground in such a way that they can be matched with one or more mating bearings.

**Floating Bearing:** A bearing mounted to move freely axially either in housing or on the shaft.

**Land:** Commonly called the O.D. on inner and the I.D of outer.

**Loads:** Radial – At right angle to axis of bearing.

**Thrust:** In the same direction as axis of shaft.

**Lubricating Groove:** A groove so placed to catch and feed lubricant to the inner moving parts of a bearing.