Общий каталог TooTool - страница 8

Technical information for Threading Technical information for Threading
Special Features
Thread Turning Method
External Thread > External Major Diameter
A thread on the external Thread The largest diameter of a screw thread Thread Inserts & Tool holder Rotation Feed Direction Helix Method Drawing No.
surface of a cylinder screw or cone EX RH Counter clockwise Towards chuck Regular
Right Hand External
Pitch Diameter EX LH Clockwise From chuck Reversed H
Major 0 <- On a straight thread, the diameter of an Right Hand Internal
IN RH Counter clockwise Towards chuck Regular H
Pitch 0 < imaginary cylinder, the surface of which cuts the IN LH Clockwise From chuck Reversed Q
Minor © < thread forms where the width of the thread and
Depth of Thread > - EX LH Counter clockwise Towards chuck Regular
-
groove are equal Left Hand External
The distance between the crest and root
EX RH Clockwise From chuck Reversed m
Minor Diameter IN LH Counter clockwise Towards chuck Regular
measured from normal to the axis
PitchJ 7 Thread
> Angle
The smallest diameter of a screw thread
Left Hand Internal
IN RH Clockwise From chuck Reversed
iHelix .
Pitch Root f Angle
! Helix Angle
Crest
The distance between the corresponding points External RH Thread External LH Thread
on adjacent thread forms measured parallel to - For a straight thread, where the lead of the thread
and the pitch diameter circle circumference form
the axis. This distance can be defined in
millimeters or by the tpi (threads per inch), which a right angled triangle, the helix angle is the angle
opposite of the lead
is the reciprocal of the pitch
Straight Thread
Nominal Diameter
A thread formed on a cylinder
The diameter of which the diameter limits are Internal Thread
derived by the application of deviation Taper Thread
A thread on the internal surface of a cylinder or cone
allowances and tolerances A thread formed on a cone

Left handed thread Right handed thread The Helix Angle ( j )
Internal RH Thread Internal LH Thread
Lead( L)
Helix angle(i)

|X Pitch diamiter ( D )

A thread which, when viewed axially, A thread which, when viewed axially, winds
winds in a counter clockwise and For a straight thread, where the lead of the thread and the
in a clockwise and receding direction
receding direction. All left handed pitch diameter circle circumference form a right angled
Threads are always right handed
threads are designated LH triangle, the helix angle is the angle opposite of the lead
unless they are specified

Machining a Multi - start Thread A thread in which the lead is an integral multiple, greater than one, of the pitch. A multi Calculating the Helix Angle Diagram
start thread permits a more rapid advance without a coarser (larger) thread form Helix Angle( J3 )
Pitch P* Pitch P*
First Start Machined Second Start Machined Third Start Machined (Final , 3 Starts Thread) 0 5j 4s 3] j = 2H
[tpi]
=m
P
Feed towards
the chuck / 7 2.25
Special _y
Toolholders 7
/ / 2.5
/
D Standard
/? helix angle / /
/
3
/ 3.5
7 7
/ / / 4
Pitch \ 1.5i oL
Shim
H1 7
7
7
7 4.5
5
Pitch Lead Pitch Standard toolholder
pocket angle
angle 1
i
/ 7 6
7 7
9
77 1
Insert Profile Style 24
• The helix angle is calculated Pitch diameter [mm] — i= 0E
50 100 150 200
Partial Profile Full Profile Full Profile for Fine Pitches Semi Full by the following formula : Feed towards 24
the tailstock \
PXN \ 11
9
P = tan - 1 JIX D
Reversed
helix angle
\ 7
6
/ \\ 5
E -1 \ 4.5
CO \ 4
\ 1.5 ° H1 \
3 - Helix angle () ° Shim \ 3.5
Standard toolholder angle
P - Pitch(mm) pocker angle \ 3
The V partial profile insert cuts without The full profile insert will form a The full profile for Fine Pitches will The Semi profile insert will form a N - No . of starts Special Toolholders
\
D - Pitch diameter (mm) 2.5
topping the outer diameter of the complete thread profile including the form a complete thread complete thread including crest
Lead = P x N The dimension H 1 (cutting
thread. The same insert can be used crest. For every thread pitch and The topping of the outer diameter is radius but without topping the outer
for a range of different thread pitches standard, a separate insert is generated by second tooth diameter
edge height ) remains ^ = - 2H =- m
• The helix angle can also be found constant with every insert /
which have a common thread angle required Mainly used for trapezoidal profiles shim combination * For Multi-start threads, use the lead value instead of the pitch
from the diagram below