GENERAL TERMS FOR THREADING
You will encounter these terms again and again in connection with taps. With the help of the sketches, you will get an understandable overview here.
General terms
General terms
γP/P1 = Chip angle
γ2P = Chip angle spiral point
γr = Back angle
N = Number of flutes
d3 = Core-diameter
Zb = Land width
Nb = Width of flutes
Explanation of signs
Spiral entry and eccentric radial thread relief
Spiral entry and eccentric radial thread relief
ha = Chamfer radial thread relief
hr = Chamfer radial thread relief per land
I7 = Length of entry
γFa = spiral point angle
Explanation of signs
Types of flutes
about 10° left spiral flutes
about 15° right spiral flutes
about 15° right spiral flutes with interrupted threads
about 35° and 45° right spiral flutes
Spiral entry with oil grooves
Types of flutes
Pf = Twist pitch
YF = Twist angle
Explanation of signs
Centrering Types
Internal Centering
Full Center Point
Half Center Point
Explanation of signs