For this purpose, a centre bore must be drilled on the right side
of the work piece.
1. Face turn the right face.
2. Insert the drill chuck (accessories) in the tailstock and
clamp the centring drill.
3. Move the tailstock with drill chuck and centring drill up to
the face of the work piece.
4. Switch on the machine and drill centre bore using the sleeve
feed.
5. Replace the drill chuck with the rotating centre 1 (Fig. 17).
6. Insert the centre in the centre bore and clamp the tailstock
3 securely.
7. Advance the sleeve 2 until all play is eliminated.
8. Secure the sleeve using a set screw 4.
Fitting change gears for thread cutting
The PROXXON Lathe PD 250/E can be used to cut metric
threads with a pitch of: 0.5 (M3), 0.625, 0.7 (M4), 0.75,
0.8 (M5), 1.0 (M6), 1.25 (M8), and 1.5 (M10).
The PD 250/E is supplied with installed gear arm and the
change gear combination for the automatic feed of 0.05
mm/revolution. It is only necessary to replace the change gears
installed on the gear arm for thread cutting.
1. Release the clamp screw 1 (Fig. 18) and tilt the gear arm 2
slightly upwards to remove the toothed belt 4.
2. Remove the fastening screws 3 and 5 from the normal gears
for the automatic feed.
The number of teeth is imprinted on all change gears.
For example, if cutting a thread with a pitch of 1.0 mm, the table
on the drive gearbox will show the following data:
mm
0.5
0.625
0.7
0.75
0.8
1.0
1.25
1.5
W 15 - gear on the main spindle with 15 teeth. This gear is
already installed on the shaft and must not be replaced.
- 22 -
Note:
Note:
W
Z
Z
L
1
2
15
15
20
40
15
15
25
40
15
15
28
40
15
15
30
40
15
15
32
40
15
15
20
20
15
15
25
20
15
15
30
20
Z
15 - Z
20 - Intermediate gear for the toothed belt of the
1
2
main spindle with 15 teeth and permanently linked gear for the
leadscrew with 20 teeth.
L20 - leadscrew gear with 20 teeth.
3. Fasten the change gear "Z
the gear arm 3 using the screw 2, pulley, reduction sleeve
and nut.
Do not yet tighten the fastening screw nut 2 (off-centre adjust-
ment must still be possible).
The change gear "Z
-Z
" runs freely between pulley and sleeve.
1
2
The washer prevents the toothed belt from becoming detached
from the gear "Z
".
1
4. Release the set screw 1, remove the change gear "L40" and
replace with the change gear "L20".
The grain of the leadscrew change "L" must always point to the
lathe chuck.
The set screw 1 must be clamped onto the flattened part of the
shaft.
Important
To ensure that there is sufficient play between the change
gears, always insert a strip of newspaper between the teeth
when pushing the change gears together. The thickness of the
newspaper should correspond to the required tooth play.
5. Push the axle of the change gear "Z
that it contacts the leadscrew gear "L" and then tighten the
fastening screw nut 2.
6. Position the short toothed belt for the connection between
the gears "W" and "Z
1
7. Push the gear arm 3 downwards and tighten the clamp
screw 4.
Thread cutting with the turning tool
For the following operations, the work piece must be machined
completely and have the correct thread outer diameter.
It is advisable to work out a chamfer at the beginning of the
thread. The thread turning tool must be clamped at an angle of
90° exactly.
1. Clamp the work piece.
2. Switch off the automatic feed and set the turning tool to the
starting position.
Important
Use the lowest speed when cutting threads and proceed with
utmost caution.
3. Press button 2 (Fig. 20) to switch on the machine (clockwise
rotation).
4. Advance the turning tool on the cross-slide 1 and engage
feed 3.
5. Switch off the machine when the required thread length has
been reached 2.
-Z
" with 15/20 teeth (Fig. 19) to
1
2
Note:
Note:
-Z
" onto the arm so
1
2
" on the main spindles.
Note: