Device for centre-punching a workpiece

The invention relates to a device for centre-punching a workpiece, with a planar bearing surface and a measuring device for determining the position of a centre mark. The device consists of a baseplate with two opposite guide grooves on which a displacing bridge is displaceably mounted in one of the two horizontal directions. For the other horizontal direction, the bridge has two guide rails on which a slide is movable free of play. Furthermore, the two guides each have a measuring scale and the parts displaceable thereon each have a pointer which is aligned with or referred to the centre-punch point. Thus, any spot can be approached in a dimensionally accurate and reproducible manner with the centre-punch point within the bearing surface of the baseplate and can be fixed by locking screws. The centre punch itself is guided vertically on the slide within a guide shaft. After the centre punch is put onto the workpiece, a centre mark can be produced at the desired location by a blow with the hammer or possibly by a pneumatic impact device. Scribing with a scriber stand and the use of marking-out colour are dispensed with, which is especially of advantage in small batches after setting the coordinate dimensions once. The device is of relatively simple construction and is inexpensive to produce; it can also be subsequently fitted to conventional surface plates.