Threading Tools Basics of Threading ■ Parts of a Screw
Thread Crest
Included Angle
Thread Root
Conical Helix
Lead Angle ( R )
Length of one turn
Pitch (P)
F
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
X î d n î P
I
tan R
=
=
X î d
P d
( Į )
Lead Angle
■ Main Screw Types and Standard Thread Patterns
Applications Symbol
Basic Profile Applications Symbol
Basic Profile Applications Symbol
Basic Profile Applications Symbol
Basic Profile
Rc(PT) Internal Thread
R0.137P Internal Thread
1/4P Internal Thread
Internal Thread
1/4P Internal Thread
Internal Thread
R0.137P
UN
27.5°
27.5°
G(PF)
55°
60°
60°
(BSPT)
UNC
Rp(PS)
M
R(PT) External Thread
UNF
External Thread
External Thread R0.137P
R0.137P
UNEF
90° 1°47'
G(PF)
External Thread 1/8P
External Thread 1/8P
(BSPT)
External Thread
Internal Thread
Internal Thread
R0.137P Internal Thread
5/16P Internal Thread
30° 30°
30° 30°
W
55°
60°
BSW
UNJ
NPT
NPTF
BSP
1°47'
1°47'
External Thread R0.137P
90°
90°
External Thread R
External Thread
External Thread
■ Tool Holder and Insert Selection Guide (SSTE Type/SSTI Type)
External Diameter (Spindle Rotation Forward)
External Diameter (Spindle Rotation Backward) Internal Diameter (Forward Spindle Rotation)
External Holder (SSTE Type) External Diameter Insert (16ER Type)
Internal Holder (SSTI Type) Internal Diameter Insert (16IR Type)
External Holder (SSTE Type) External Diameter Insert (16ER Type)
Shim YE3-3P/YE3-2P YE3-1P/YE3/YE3-1N
Shim YI3-3P/YI3-2P YI3-1P/YI3/YI3-1N
Shim YE3-3P/YE3-2P YE3-1P/YE3/YE3-1N
(
)
(
)
(
)
External Holder (SSTE Type) External Diameter Insert (16ER Type)
External Holder (SSTE Type) External Diameter Insert (16ER Type)
Internal Holder (SSTI Type) Internal Diameter Insert (16IR Type)
Shim
Shim
Shim
(
)
(
)
(
)
YI3-2N/YI3-3N
YE3-2N/YE3-3N
YE3-2N/YE3-3N
■ Threading Method and Angle of Insert
Right Threading
Left Threading
≒ Lead Angle ( E )
Shim Angle
≒ Negative Lead Angle
Shim Angle
( E )
Standard Holder Inclination (1.5°)
Standard Holder Inclination (1.5°)
F62
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