Punches are used in order to make certain dimensional features of the layout permanent. There are two types of punches. They are centre punch and prick punch made of high carbon steel, hardened and ground.
Types of Punches are as follows
- Centre Punch
- Prick Punch / Dot Punch
1. Centre Punch
The angle of the point is 90° in a centre punch. The punch mark made by this is wide and not very deep. This punch is used for locating centre of the holes. The wide punch mark gives a good seating for starting the drill.
2. Prick Punch / Dot Punch
The angle of the prick punch is 30° or 60°. The 30° point punch is used for making light punch marks needed to position dividers. The divider point will get a proper seating in the punch mark. The 60° punch is used for marking witness marks and called as dot punch. The witness marks should not be close to one another.