Page 380 - THREADING CATALOG

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
d2
d4
D d3

Cm L1 L4 L2 S
L first taper tap second tap bottoming tap
D - major diameter
d2 - shank diameter
d3 - chamfer diameter Tap Styles for Hole Types
d4 - neck diameter throughole
DIN 376
Cf 1 straight fluted tap with spiral point
L6
d4
D d3
2 left-hand spiral fluted tap
L1 L4 L2
L
L - total length
L1 - thread length 3 straight fluted tap with long chamfer lead
L2 - shank length blind hole
L3 - square length
L4 - neck length
L5 - chamfer length 4 right-hand spiral fluted tap
L6 - flute length
S - square size
Cm - center male
Cf - center female 5 straight fluted tap with short chamfer lead
Front and end configurations according to DIN2197
Chamfer Lead Forms According to DIN 2197
A 6-8 threads Form A Front End Shank End
long, 6-8 threads for 1 External Center 4 External Center
short through holes.

B 3.5-5 threads Form B 2 Stepped External Center 5 Chamfer
medium, 3.5-5 threads, with
spiral point for all through holes
and deep tapping holes.
C 2-3 threads Form C 3 Internal Center 6 Internal Center
long, 2-3 threads for blind holes
and generally for aluminum
grey cast iron and brass.
D 3.5-5 threads Form D Thread Dia. Tap
medium, 3.5-5 threads for Range (mm) Front End Shank End Standard
through and blind holes
with sufficient runout. ≤Ø6 1 4 5 DIN352
E 1.5-2 threads Form E Ø7 1 2 4 5 6 DIN371
extremely short, 1.5-2 threads ≥Ø8 1 2 3 5 6 DIN376
for blind holes with little runout
depth. Avoid use if possible.
F 1-1.5 threads Form F
extremely short, 1-1.5 threads
for blind holes with little runout
depth. Avoid use if possible.

ISCAR
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