Page 722 - Iscar

USER GUIDE
TAPS Tap Nomenclature and Standards

DIN 371 DIN 376

L5 L3 Cf
d2 L6
d4 d4
D d3 D d3
L1 L4 L2 L1 L4 L2
Cm S L
L
D Major diameter L Total length
d2 Shank diameter L1 Thread length
d3 Chamfer diameter L2 Shank length
d4 Neck diameter L3 Square length
L4 Neck length
L5 Chamfer length
L6 Flute length
S Square size
Cm Center male
Chamfer Lead Forms According to DIN 2197
L Total length Cf Center female

6-8 threads
A Form A
Long, 6-8 threads for
short through holes.

3.5-5 threads Form B
B Medium, 3.5-5 threads,
with spiral point for all through
holes and deep tapping holes.

2-3 threads
Form C
C Long, 2-3 threads for blind
holes and generally for aluminum
grey cast iron and brass.

3.5-5 threads
Form D
D Medium, 3.5-5 threads for
through and blind holes
with sufficient runout.
1.5-2 threads
Form E
E Extremely short, 1.5-2 threads
for blind holes with little runout
depth. Avoid use if possible.
1-1.5 threads
Form F
F Extremely short, 1-1.5 threads
for blind holes with little runout
depth. Avoid use if possible.

Chamfer Lead Length for Sets of 3 Hand Taps

ca. 6 threads ca. 4 threads ca. 2 threads

First taper tap Second tap Bottoming tap

ISCAR
718 ISCAR
718