Threading Tools Basics of Threading ■ Parts of a Screw
Thread Crest
Included Angle
Thread Root
Conical Helix
Lead Angle ( R )
Length of one turn
F
Pitch (P)
Effective Diameter (d)
Lead Angle
External Thread
Internal Thread
Effective Diameter
Ɣ Lead Angle Calculation
R I n
(d) (P) ( I )
: Diameter of imaginary cylinder that passes through the thread at the point where the groove and ridge widths are equal : Distance between two ridges adjacent to each other : Distance the screw thread moves axially in one turn (On a single threaded screw, the lead and pitch are identical.) : Angle made by the conical helix of the thread ridge at a pitch diameter with a plane perpendicular to the axis
: Lead Angle : Lead : No. of Threads : Pitch : Effective Screw Diameter
Pitch Lead
I
X î d n î P
tan R
=
=
X î d
P d
( Į )
Lead Angle
■ Main Screw Types and Standard Thread Patterns
Applications Symbol
Basic Prole Applications Symbol
Basic Prole Applications Symbol
Basic Prole Applications Symbol
Basic Prole
Rc(PT) (BSPT) External Thread R(PT) (BSPT) Internal Thread
1/4P Internal Thread
R0.137P Internal Thread
1/4P Internal Thread
Internal Thread
G(PF) Rp(PS) External Thread G(PF) Internal Thread
R0.137P
UN UNC UNF UNEF
27.5°
27.5°
55°
60°
60°
M
External Thread R0.137P
R0.137P
90° 1°47'
External Thread 1/8P
External Thread 1/8P
External Thread
R0.137P Internal Thread
5/16P Internal Thread
Internal Thread
Internal Thread
30° 30°
30° 30°
W BSW BSP
55°
60°
UNJ
NPT
NPTF
1°47'
1°47'
External Thread R0.137P
90°
90°
External Thread R
External Thread
External Thread
■ Tool Holder and Insert Selection Guide (SSTE / SSTI)
External Diameter (Spindle Rotation Forward)
External Diameter (Spindle Rotation Backward) Internal Diameter (Forward Spindle Rotation)
External Holder (SSTE) External Diameter Insert (16ER)
Internal Holder (SSTI) Internal Diameter Insert (16IR)
External Holder (SSTE) External Diameter Insert (16ER)
Shim YE3-3P/YE3-2P YE3-1P/YE3/YE3-1N
Shim YE3-3P/YE3-2P YE3-1P/YE3/YE3-1N
Shim YI3-3P/YI3-2P YI3-1P/YI3/YI3-1N
External Holder (SSTE) External Diameter Insert (16ER)
External Holder (SSTE) External Diameter Insert (16ER)
Internal Holder (SSTI) Internal Diameter Insert (16IR)
Shim YE3-2N/YE3-3N
Shim YE3-2N/YE3-3N
Shim YI3-2N/YI3-3N
■ Threading Method and Angle of Insert
Right Threading
Left Threading
Shim Angle
≒ Lead Angle ( E )
≒ Negative Lead Angle
Shim Angle
( E )
Standard Holder Inclination (1.5°)
Standard Holder Inclination (1.5°)
F72
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