Thread Cutting; Drilling Operation - Promac PBD-2870 Manuel D'utilisation

10.7 Thread cutting

Threading is performed in multiple passes with a threading
tool.
Each depth of cut should be about 0,2mm and become less for
the finishing passes.
A) Cut inch and metric threads:
Set the machine up for the desired threading pitch (see
chapter 8.2).
Select the lowest possible spindle speed.
Engage the halve nut (AA, Fig 10-6).
NOTE: The halve nut must stay engaged during the entire
threading process.
- Set the tool up for the threading pass.
- Start the motor.
- When the tool approaches the end of cut, stop the motor and
at the same time back the tool out, so that it clears the thread
diameter.
- Start the motor in reverse direction, let the cutting tool travel
back to the starting point.
Repeat these steps until you have obtained the desired results.
B) Cut metric threads with threading dial
On most metric threads the threading dial (CC, Fig 10-8) can be
used.
The halve nut can be opened at the end of cut, rather than the
motor being stopped and reversed.
Figure 10-8: Threading Dial
Select threading dial gear 28T or 30T
The halve nut may only be engaged at the corresponding
graduation match on the threading dial (Fig 10-9).
Figure 10-9: Threading dial setup
Note:
For thread pitches of 0,2/0,3/0,5/0,6/0,75/ 1,0/ 1,5/3 mm the
half nut can be engaged at any point.
(lead screw pitch = 3 mm = can be divided by thread pitch).

10.8 Drilling operation

Use a drill chuck with MT2 arbor (option) to clamp centre drills
and twisted drills in the tailstock (Fig 10-10)
Figure 10-10: Drilling operation
For recommended speeds refer to section 10.4
To eject the drill chuck, fully retract the tailstock quill.
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