Centre Punch

Centre Punch The centre punch is used for making marks for the point of spring dividers and to mark the position of holes. The centre punch should be tilted at an angle to position the point accurately. Centre punches are made from high carbon steel. The points are hardened and tempered and ground to angles of 60° or 90°.

Centre Punch Sometimes separate punches are used to mark, or dot lines and to mark the position of holes. The one used to dot lines is called a dot punch and is ground to an angle of 60°. A centre punch is used to mark the centre for holes and the point is ground to an angle of 90°. Dot punches are used to identify lines.

Spring Dividers

Spring Dividers The dividers is used for drawing circles and arcs on metal. Also used for transferring measurements from one piece to another. The dividers can be set by adjusting the nut until the points fit into the required graduations on the rule.

Spring Dividers There are two types of dividers, the spring type and the firm joint type. The spring type is the most widely used. The size of the dividers is given by the length from the centre of the roller to the point of the leg. The legs are made from tool steel with hardened points. The legs must be the same length.

Odd Leg Callipers

Odd Leg Callipers One leg is either curved at the top or has a locating spur. The other leg has a scriber attached to it. The Odd Leg Callipers is used for- Scribing a line parallel to a straight edge Scribing a line on a round bar on the lathe