Basic Elements › Measuring instruments

THE CALIPER (VERNIER CALIPER)

Caliper (vernier caliper) with digital dial

What is a caliper (vernier caliper)?

The caliper (vernier caliper), sometimes called sliding caliper, is a measuring instrument used in horology to accurately determine the external and internal dimensions, as well as the depths of components and mechanisms.

Function and use

In horology, where dimensional tolerances are often very tight, the Caliper (vernier caliper) allows parts to be measured with a precision greater than that of classic rulers. It is used to check the width, diameter, thickness or depth of components, tools, etc.

Characteristics

• Material : Generally made of stainless steel, it offers robustness, durability and corrosion resistance.
• Graduations : Depending on the model, the graduations can be analogue (with vernier) or have an analogue or digital dial, generally offering accuracies down to the hundredth of a millimetre.
• Main parts : It comprises two sliding jaws – one fixed and one mobile – for taking outside measurements, along with specific tips for measuring the inside of parts and a depth rod.
• Dimensions : Compact models, suited to the size of watchmaking components, are favoured for easy handling in the workshop.

Importance in watchmaking

The Caliper (vernier caliper) is an essential tool for guaranteeing the quality and conformity of parts inside watches. It is used to check tolerances, which are essential for ensuring the proper functioning and longevity of the watch mechanism. In addition to other instruments such as the metal rule and the micrometre, it contributes to the precision and finesse of horological work.