GAUGES

A Boley gauge is an instrument used in Pedo (pediatric dentistry) for space analysis and band selection. Boley gauges are accurate to tenths of a millimeter.

How to use a Boley Gauge

A Boley gauge has a fixed scale and a sliding scale. Begin by looking at the fixed scale where the bold face numbers are in cm. The 1 and 2 on the fixed scale represent 1cm (10mm) and 2cm (20mm) respectively.

The zero mark is the first tick mark on the sliding scale. The zero mark determines the whole mm amount depending on where it is located relative to the fixed scale. For example, if it's between the 11mm and 12mm tick mark on the fixed scale it's 11mm. If it's between the 12mm and 13mm the whole mm amount is 12mm.

As you look along the sliding scale find which tick mark on the sliding scale most closely lines up with a tick mark on the fixed scale. That tick mark is going to represent your tenths of a mm.

Remember:
The zero tick mark on the sliding scale does not count as 1.