Page 369 - Carbide drills I Thread cutting tools 2023

Formulas and abbreviations

a Dimension of square end
d Nominal diameter of the thread
Drilling diameter of the drill / thread milling cutter
d 1
Diameter of the shank
d 2
Diameter of the thread milling cutter
D 1
d/D 1 Ratio of diameters for the determination of the feed speed
Rk Corrected milling cutter radius for ISO 2 (6H) thread tolerance
(radius to be programmed in the machine control system)
Feed per tooth
f z
l Length of threaded section of the tap / thread former / thread milling cutter
Neck length of the tap / thread former / thread milling cutter
l 1
Flute length of the tap
l 3
L Overall length of the tap / thread former / thread milling cutter
Countersinking depth of the thread milling cutter with chamfer
L K
n Spindle speed
P Thread pitch
Cutting speed
v c
Feed rate
v f
Feed speed in the tool centre
v fc
Number of flutes on the tap and thread cutter
Number of form edges of cold forming taps
∆ Diameter differences of the thread flank, the thread outside and the thread core in the application
class 2 (ISO 2) according to DIN 22857
Mechanical tensile strength
R m
HRC Hardness according to Rockwell C
HV Hardness according to Vickers
HB Hardness according to Brinell

Spindle speed v · 1000 1
n = c
d 1 · π min
Cutting speed
d · π · n m i
v c = 1000 min

Feed rate Taps mm
v f = P · n min

Feed rate Thread milling cutters mm
v f = f · z · n min
z

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