Far Tools TDM 400B, Manual, Page: 20 / 40

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The tool is aligned with the part using a centre gage. This centre gage is useful when
checking tool sharpening.
1/ Once the tool is correctly sharpened and aligned, set the rpm, a setting that will be far
slower than the theoretical rpm rate, (approx. 50% less).
Example: For an M 20 x 2.5, semi-hard steel=30
setting that will be far slower than the theoretical rpm rate, (approx. 50% less).
Example: For an M 20 x 2.5, semi-hard steel=30 132/ To cut a thread, a speed of 220 rpm
will be used
2/ Then the pitch will be set by changing the gears. For a 2.5 mm pitch, the choice will be
A=60 teeth, B=120 teeth and D=24 teeth and lever 3 will be set to I,
3/ Before starting machining, calculate the tool penetration depth using the following
formula:
Example:
For a 2.5 mm pitch: 0.61 x 2.5 = 1.525 mm in radius
4/ Pull the part far enough out of the chuck when cutting a thread so that no collision
occurs between the thread cutting tools and the chuck jaws (as the chuck does not have
a brake). The technique used to stop thread cutting is first of all to shutdown the motor
and then to quickly withdraw the tool.
5/ Start up. Place the tool at a tangent to the part. The part has a nominal diameter of
20. For an M 20 x 2.5 mm thread, make a pencil mark on the Vernier callipers. Disengage
the tool to the right on removing it from the part.
Take a 0.5 mm cutting depth (for the first pass only), i.e. 10 divisions on the Vernier cal-
lipers. Stop the machine.
Engage lever 2 (leadscrew clutch),
Lubricate the part with cutting oil.
Start up and place one hand on wheel 14 to disengage the tool when it reaches the de-
sired thread length, then place the other hand on the motor stop button.
Reverse the machine to return the tool to its starting position, and start another 0.25
pass (5 divisions on the Vernier calliper in addition to the 10 divisions already taken du-
ring the first pass)
- Repeat the operation six times to achieve the theoretical 1.525 cutting depth.
- After the final pass, perform one more blank pass to correct tool part flex,
- Back off the tailstock centre and try the thread with a 20 mm 2.5 pitch nut.
Pdp = 0,61 x P
N =
1000 x 30 = 477 tr/ min
π x 20
WARNING: Do not disengage lever 2 for the tool may no longer fit into
the same pitch during the next pass.
114135-Manual-D-EN.indd 20 21/03/12 10:44:59