From DT Online
Centre Punches are ground to a strong point with an included angle of 90 degrees by holding them Tangentially to a Tool Grinder and rotating them. This tends to create grinding marks which run along the point and strengthen it rather than weakening it by going across (i.e. in a similar manner to a Scriber).
Features and Uses
To stop a drill bit skidding about a metal surface, these are used to make a small indentation to locate the drill centre.
Note: Hold the punch to an angle to position on centre then raise to the vertical and strike it sharply with a hammer - but only once - striking several times may cause the punch to bounce around.
- All punches shown have a good knurled grip.
- Those with a square head are less likely to roll off the bench.
- The specialised 'bell' centre punch is used to mark the centres on the end of round bars and can be used as an alternative to Centre Drilling on a lathe.
|Stanley Centre Punch 0 58 120||Draper 84456 4mmx100mm Centre Punch||Starrett 117D Centre Punch with Round Shank||Spear & Jackson 4mm x 100mm (4inch) Centre Punch||RDGTOOLS Engineers Bell Punch "Centre find every time"|