Far Tools TDM 400B, Manual, Page: 19 / 40

© FAR GROUP EUROPE
CUTTING
OUTER AND INNER THREAD CUTTING
a/ Comprises cutting a part that has already been drilled and
bored to obtain a spacer or washer,
b/ Use a cutting tool. Bring the tool tip to the same height as
the axis (again using shims) or a little below the part centre,
c/ Start the machine after first setting the rpm,
d/ Offset your tool to the left (wheel 17) using a straight edge to check the distance
between the part face and the right hand side of your tool. Stop as soon as you obtain
the desired distance and add 1 mm to it to correct the face surface.
e/ Manually and regularly advance the tool using wheel 14. We recommend lubricating
(with soluble oil and water) using a brush. As soon as the tool drills through into the
bore, reverse and disengage to the right
Designation: Threads are designated by the M symbol, followed by their diameter and
pitch in mm, separated by a multiplication sign. Example: M 30 x 3.5, i.e. M 30 for a 30
diameter thread with a 3.5 mm thread pitch. Standard threads are:
/ Outer thread: The tool profile sharpening angle for cutting a metric thread is 60°, The
tool profile sharpening angle for cutting a Whitworth thread (English pitch) is 55°,
CUTTING A TRIANGULAR THREAD
Tool penetration
- Normal penetration (see Fig. below).
The tools are aimed and their profiles sharpened to 60°
or 55° using angle centre gages.
Tool height position. Absolutely aligned with the tip
axes (part axis).
nominal Diameter M Typical pitch P (mm)
M 3 0,6
M 4 0,7
M 5 0,8
M 6 1
M 8 1,25
M 10 1,50
M 12 1,75
M 14 2
M 16 2
M 18 2,5
M 20 2,5
M 22 2,5
M 24 3
M 27 3
M 30 3,5
N = 1000 x V
π x D
Outer
threading
tool
Outer threa-
ding tool
Cutting tool
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