Page 627 - Yamawa_European_Catalogue_YEU23

4. Cutting angle and thread relief

Intro

Cutting angle and Chamfer relief angle θ: Cutting angle γ: Chamfer relief angle
SP
Chordal Hook Angle Rake Angle Tangential Hook Angle

SL

PO

ST
Cutting angle of hook face. Cutting angle of rake face. Cutting angle of hook face.
The angle between the center line passing The angle between the center line passing The angle between the center line passing
the cutting edge and the straight line linking the cutting edge and the straight line linking the cutting edge and the straight line tan-
the cutting edge with the thread root. the cutting edge with thread root. gent to the rake face on the cutting edge.
ROLL

Thread relief S: Indicator drop for thread relief
CARBIDE
Concentric-unrelieved Con-eccentric thread relief Eccentric thread relief
(A)

LONG
(B)

HAND
TAPS

EG (STI)

No relief exists at land. Start (A) and heel (B) Radial relief in the thread form starts at the Radial relief in the thread form starts at the
of thread land have same concentricity. back of a concentric margin. cutting edge and continues to the heel.
SPECIAL
THREADS,
GAUGES
Land A
The amount of cut portion
THREAD
Land D Please refer to the pictures shown. For the taps with MILLS
4 flutes and 3 threads chamfer, the cutting operation
progresses in order from the edge of A1, B1, C1, D1…
Land B
Land A A2, B2…A4. Tap end is usually smaller than the size
of bored hole, and A1 may not make any cutting
operation. DIES
Land C
Land B t: Amount of cut portion per blade
CENTER
DRILLS
Land C
t
Technical
info
Land D
Tapping direction Bored hole diameter
625