Page 643 - Yamawa_European_Catalogue_YEU21

5. Tapping Torque

Intro

Cutting Torque Line
Cutting torque line for diff erent kinds of taps (straight fl uted tap, spiral fl uted tap, spiral pointed tap) is shown below. SP

Tap : HSS ISO2(6H) M8×1.25 Bored hole size : 6.8 mm
Cutting speed : 6 m/min Cutting oil : Oil
Workpiece material : Ck60 Machine : Drilling machine
Tapping type : 10 mm Through hole Measurement equipment : Piezoelectric torque tester SL

Type of tap Torque line Description
PO
Plateau is observed since whole chamfer threads
5P
enter the workpiece material.
Straight fl uted tap ST
Plateau is also observed since whole short chamfer
1.5P
threads enter the workpiece material. Tapping
(1.5 threads)
process time is shorter than that of the 5P tap.
ROLL
Spiral fl uted tap pulls out the chips, good choice
Spiral fl uted tap (2.5 threads) for blind hole tapping. The cutting torque of spiral
fl uted taps is lower than that of the hand taps.
CARBIDE
Spiral pointed tap pushes out the chips forward.
It is good choice for through hole use. Cutting
Spiral pointed tap (5 threads)
torque is the smallest among the diff erent tap
shapes. LONG

The cutting torque changes depending on the kind of taps, cutting chamfer, number of fl utes, workpiece materials and their hardness,
lubrication types, and chips.
HAND
TAPS
Comparison of Cutting Torque by Different Type of Taps
Cutting torque of straight fl uted tap (HT), and spiral fl uted tap (SP), and spiral pointed tap (PO) diff ers, shown in the chart below.

TAPPING CONDITION EG (STI)
Tap: HSS ISO2(6H) M10×1.5
Cutting speed: 10 m/min
Workpiece material: Ck60 SPECIAL
Hole condition: 20 mm through hole THREADS,
Bored hole size: Ø 8.5, drill GAUGES
Lubrication : Straight oil
Machine: Radial drilling machine

Measurement equipment: Piezoelectric torque tester
THREAD
MILLS
Tapping torque

If the cutting torque of straight fluted tap is DIES
assumed as 100, the cutting torque of other taps is
as follows :
CENTER
Straight fl uted Tap : 100 DRILLS
Spiral fl uted Tap : 70-75
Spiral Pointed Tap : 60-65

HT SP PO Technical
(5P) (2.5 threads) (5 threads) info

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