Sometimes the only way to hold a workpiece for machining or secondary operations is by gripping it from within - Elesa s GN411 does exactly that - it features an expanding clamp with a multipoint contact system. The precise self-centring action of the GN411 provides solid stable clamping of workpieces with uneven or irregular external surfaces - such as castings.
GN411 clamps are available to accommodate bores of 12mm up to 102mm. Operation is manually by means of clamping screw or by hydraulic/pneumatic activation. The unit contains a circular cage with 3 or 6 hardened balls (dependant upon size of unit), which are forced outwards over an ingenious double cone ramp system, thus exerting an outward thrust and gripping the workpiece securely. For delicate materials the GN411 can be supplied with barrel shaped hex section segments in place of balls. These offer a more gentle surface gripping action by spreading the load over a larger area. Further information on Elesa (UK) Ltd products may be found at: www.elesa.co.uk