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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
L1 - Thread length
L2 - Shank length
L3 - Square length
L4 - Neck length 3 Straight fluted tap with long chamfer lead
L5 - Chamfer length
L6 - Flute length Blind hole
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
spiral point for all through holes
and deep tapping holes. Front and End Configurations According to DIN2197
2-3 threads Form C Front End Shank End
C Long, 2-3 threads for blind holes 1 External Center 4 External Center
and generally for aluminum
grey cast iron and brass.
3.5-5 threads Form D
D Medium, 3.5-5 threads for through 2 Stepped External Center 5 Chamfer
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 3 Internal Center 6 Internal Center
depth. Avoid use if possible.
1-1.5 threads Form F
F Extremely short, 1-1.5 threads
for blind holes with little runout Thread Dia.
depth. Avoid use if possible. Range (inch) Front End Shank End Tap Standard
≤.236 1 4 5 DIN352
.276 1 2 4 5 6 DIN371
≥.315 1 2 3 5 6 DIN376

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