THE CENTRE AND DOT PUNCH
V. Ryan © 2002 - 2009
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The centre punch is made form mild steel with the
point hardened and tempered so that it withstands impact with the
material it is marking. It is normally used to mark the centre of a hole
to be drilled either by hand or on the drilling machine. |
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Both the centre and dot punches are used in the same way. A ball pein hammer is used to tap the head of the punch and this delivers enough force to the point of the punch to put a small indentation into the surface of the material. |
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TWO USES OF THE DOT PUNCH AND CENTRE PUNCH |
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1. A hole is to be drilled in this material. One possible danger is that the hand drill will slip when drilling first starts. If a centre punch is used to mark the point of drilling, slipping is unlikely to happen. |
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2. The copper is to be cut along the line. To make it easier to see a dot punch had been used to emphasise the line. |
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