SPANNTOP [nova] – Safety
Chuck size
Maximum chuck length
[mm]
Mq max [Nm]
32
< 120
120
42
< 125
210
52
< 125
210
65
< 140
300
80
< 140
360
100
< 160
450
125
< 200
650
140
< 200
690
160
< 200
750
Table 10: Maximum permissible moment Mq due to transverse force Fq
With extended chuck length, the maximum permissi-
ble cutting force must be reduced in the ratio of the
feed lengths, e.g. size 32, L=150mm
120mm
150mm
∗
120Nm
=
96Nm
2.10.6 Sample calculation
Applied to a specific example
Longitudinal turning of an offset shaft of 16MnCr5
[pre-machined clamping diameter] without tailstock
support in horizontal position.
Workpiece data
Clamping diameter d
sp
= 60 mm
Workpiece length
L
w
=150mm [151,5mm unmachined]
Machining diameter – turning operation
d
z
= 57,0 mm
Workpiece mass m
w
= 3,3 kg
→ F
G
= m
w
* 9,81 m/s
2
→ F
G
= 33 N
Process data
Speed n=800 1/min
Feed f=0,25 mm
Clamping depth a
p
=1,5 mm
Use of cooling lubricant
Clamping length L
sp
=20mm
34