Operation
Version 1.0 - 2020-12-22
143
Translation of original instruction
TU2506VB
EN
T
U
2506V
B_GB
_4.
fm
4.18.4 Examples for thread cutting
As an example, a metric external thread M30 x 1.0 mm made of brass is being machined.
Steel sheets are to be laid under the complete tool holder or turning tool to achieve exactly
the turning center.
The lowest spindle speed is set so that the lathe will not coast too long !
Mount gear pairing for pitch 1.0 mm in the change gear !
The cutting point is slit slightly by turning the handwheel of the cross slide the scale is turned to
zero. This is the point of departure for the infeed of the depth of thread.
The scale of the top slide is also set to zero (this is important for the lateral offset when turning
threads with larger pitches).
The cutting point is set just in front of the starting point of the start of the thread by actuating the
handwheel of the lathe saddle.
In standstill of the lathe a connection to the lead-screw is made by shifting the operating lever of
the lead-screw nut. With this connection, the adjusted thread pitch is transferred to the lathe
saddle and to the tool holder.
Abb.4-36: Thread cutting
The outer diameter had been turned to 30.0 mm and the
tool holder is clamped in the quadruple holder for thread-
ing aligned angular to the rotation axis. The height of cen-
tres is checked (as described).
Abb.4-37: radial infeed
The depth of thread is manufactured in
various passes. The infeed is to be
reduced after each pass.
The first pass takes place with a infeed of
0.1 to 0.15 mm.
For the last pass the infeed shall not be
below 0.04 mm.
For pitches up to 1.5 mm the infeed may
be radial.
For our example 5 to 7 passes are being
determined.
Abb.4-38: Alternately infeed
For larger pitches the alternately flank
infeed is selected. The top slide is from the
2nd passage in each case 0.05 - 0.10 mm
adjusted alternately to the left and right.
The last two passes are performed with-
out lateral offset. When the depth of
thread is achieved, two passes are per-
formed without infeed.
To machine internal threads, about 2
passes shall be selected additionally for
the infeed (drill rods are more instable).
