Hollow Rod Cylinder

single acting, spring return,
max. operating pressure 400 bar.

Article no. push-pull force
at 100 bar
push-pull force
at 400 bar
Stroke H
effective piston area
Spring force min.
63768 6921-70x6 17,8 71 6 11 18,5 700 1675
63149 6921-100x10 24,4 101 10 26 25,9 1500 4800


Cylinder barrel from steel, burnished. Piston and piston rod case hardened and ground. Retraction by disc springs. 1 wiper. Piston rod with internal thread and two flats (size 70 x 6) or hexagon (size 100 x 10). Built-in sintered bronze filter. Oil supply via threaded port.


When workpieces are clamped onto a machine tool table, the hollow rod cylinder can be screwed onto the clamp bolt and be joined to the clamp by the two threads in the body. Also suitable for holding and clamping devices directly on a machine tool table. The hollow rod cylinder is designed for use in combination with tempered bolts of material grade 8.8 for size 100x10 and material grade 12.9 for the size 70x6. In case bolts of material grade 8.8 and grade 10.9 are used the pressure has to be reduced for size 70x6 for continuous operation (see diagramme).


Protected against contamination and chips by a wiper. High forces in a small design.


For single acting cylinders there is risk of sucking in coolant during the return stroke. In this case the cylinders have to be protected against the direct effect of coolant. The built in sinter metal breather should be protected.

  • dimensions table
    Article no. Piston
    A B dia. C dia. D
    E F G K L M R S
    63768 6921-70x6 55 58 10 16,5 75 26 50 M8 13 65 M16 G1/4 SW22
    63149 6921-100x10 70 85 10 25,0 100 56 70 M10 16 97 M24 G1/4 SW36