Glass cutter

[2] In the Middle Ages, glass was cut with a heated and sharply pointed iron rod.

Between the 14th and 16th centuries, starting in Italy, a diamond-tipped cutter became prevalent which allowed for more precise cutting.

In 1869, the wheel cutter was developed by Samuel Monce of Bristol, Connecticut, which remains the current standard tool for most glass cutting.

[3] A glass cutter may use a diamond to create the split, but more commonly a small cutting wheel made of hardened steel or tungsten carbide 4–6 mm in diameter with a V-shaped profile called a "hone angle" is used.

[4] Their main drawback is that wheels with sharper hone angles will become dull more quickly than their more obtuse counterparts.

The ratio between the arc of the wheel and the pressure applied with the tool has an important bearing on the degree of penetration.