�y��vlog

He kept a toffee hammer and a centre punch in his car.

Centre Indicators.—On account of the difficulty of ascertaining when a centre runs quite true, or when a very small hole or fine cone as a centre punch mark runs true when chucked in a lathe, the centre indicator is used to make such tests, its object being to magnify any error, and locate its direction.

The point a of the centre punch shown in Fig.

The centre punch must be held upright or it will move laterally while entering the metal.

The part b of the centre punch is tapered so as to obstruct the vision as little as possible, while it is made hexagon or octagon at the upper end to afford a better grip.