Page 53 - HOLE MAKING CATALOG p311-382

USER GUIDE TAPS

Tap Nomenclature and Standards

DIN 371 Chamfer Lead Length for Sets of 3 Hand Taps

L5 L3 ca. 6 threads ca. 4 threads ca. 2 threads
d4 d2

D d3

Cm L1 L4 L2 S

D - Major diameter L First taper tap Second tap Bottoming tap
d2 - Shank diameter
d3 - Chamfer diameter Tap Styles for Hole Types
d4 - Neck diameter
Throughole

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 3 Straight fluted tap with long chamfer lead
L1 - Thread length Blind hole
L2 - Shank length
L3 - Square length 1 Right-hand spiral fluted tap
L4 - Neck length
L5 - Chamfer length
L6 - Flute length
S - Square size
Cm - Center male
Cf - Center female

Chamfer Lead Forms According to DIN 2197

6-8 threads Form A
Long, 6-8 threads for
A

short through holes. 2 Straight fluted tap with short chamfer lead

3.5-5 threads Form B Front and End Configurations According to DIN2197
Medium, 3.5-5 threads, with
B 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 2 Stepped External Center 5 Chamfer
C Long, 2-3 threads for blind holes
and generally for aluminum
3.5-5 threads grey cast iron and brass.

D Form 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 Thread Dia. Front End Shank End Tap Standard
Extremely short, 1.5-2 threads Range (mm)
E for blind holes with little runout 1 45 DIN352
depth. Avoid use if possible. ≤Ø6 12 456 DIN371
1-1.5 threads Ø7 123 56 DIN376
Form F ≥Ø8
F Extremely short, 1-1.5 threads
for blind holes with little runout
depth. Avoid use if possible.

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