PUNCH

PUNCH
A punch is a hard metal rod with a shaped tip at one end and a rounded
butt at the other end that is usually struck by a hammer.
There are many types of punches,
and the most commonly used ones
for marking out are:

A) Center punch: It is used as an
aid to drilling operations. A center
punch forms an indent in which
the tip of the drill will fit. A center
punch has a point angle of 90° as
shown

B)Prick punch: It is used for
layout. A prick punch produces a
smaller indentation than a center
punch, which acts as a useful
datum point in layout operations.
A prick punch has a point angle of
60° as shown

        PUNCH                                                       ANGLE

1. Centre Punch                                               1.90

2. Dot Punch                                                    2. 60

3. Prick Punch                                                 3. 30