Base Circle
Base Circle formula |
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BC=PD⋅cos(PA) | ||
Symbol | English | Metric |
BC = base circle | in | mm |
PD = pitch diameter | in | mm |
PA = pressure angle | deg | rad |
Base circle, abbreviated as BC, is a circle from where involute portion of tooth profile will be produced. The base circle of a gear is an important concept in gear geometry. It is a theoretical circle that is used as a reference in the design of involute gears. The base circle is defined as the circle from which the involute curve of the gear tooth is generated.