Page 68 - Aluminum_Machining_catalog_2023

USER GUIDE
TAPS

Tap Nomenclature and Standards
DIN 371 Chamfer Lead Length for Sets of 3 Hand Taps
L5 L3 ca. 6 threads ca. 2 threads
d2
d4 ca. 4 threads
D d3

Cm L1 L4 L2 S
L First taper tap Second tap Bottoming tap
D - major diameter Tap Styles for Hole Types
d2 - shank diameter throughole
d3 - chamfer diameter
d4 - neck diameter
DIN 376 1 straight fluted tap with spiral point
Cf
L6
d4
D d3

L1 L4 L2 2 left-hand spiral fluted tap
L
L - total length
L - total length
L1 - thread length
L2 - shank length
L3 - square length 3 straight fluted tap with long chamfer lead
L4 - neck length
L5 - chamfer length blind hole
L6 - flute length
S - square size
Cm - center male
Cf - center female 1 right-hand spiral fluted tap
Chamfer Lead Forms According to DIN 2197
6-8 threads Form A
A Long, 6-8 threads for
short through holes.
2 straight fluted tap with short chamfer lead

3.5-5 threads Form B
B Medium, 3.5-5 threads, with Front and End Configurations According to DIN2197
spiral point for all through holes Front End Shank End
and deep tapping holes. 1 External Center 4 External Center

2-3 threads Form C
C Long, 2-3 threads for blind holes
and generally for aluminum
grey cast iron and brass. 2 Stepped External Center 5 Chamfer

3.5-5 threads Form D
D Medium, 3.5-5 threads for through
and blind holes with sufficient runout. 3 Internal Center 6 Internal Center

1.5-2 threads Form E
E Extremely short, 1.5-2 threads
for blind holes with little runout Thread Dia.
depth. Avoid use if possible. Range (mm) Front End Shank End Tap Standard
≤Ø6 1 4 5 DIN352
Ø7 1 2 4 5 6 DIN371
1-1.5 threads Form F ≥Ø8 1 2 3 5 6 DIN376
F Extremely short, 1-1.5 threads
for blind holes with little runout
depth. Avoid use if possible.

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