Lipped domed acrylic crystal

Some crystals are not simply pressed into the bezel: they have a rim, called a lip, which follows the shape of the case. This is the case with this lipped domed acrylic crystal.

Shape and use

The central dome extends into a peripheral lip that fits into the bezel or covers it, depending on the case. This profile is often found on old and vintage watches; acrylic (Plexiglas or hesalite) was the most common material on them, as on pocket watches. This crystal is generally suitable for watches whose original crystal had the same rim: compare the profiles carefully before ordering.

What acrylic offers, and its limits

Lightweight, Plexiglas does not shatter into sharp fragments, an asset for the safety of the movement and dial. Its low hardness, however, makes it prone to scratches. Polishing is usually enough to remove light marks: the guide to polishing an acrylic crystal shows how.

Taking the right diameter

Measure the old crystal with a calliper. For this domed crystal, the diameter is taken at the base, on the outer edge of the lip. Repeat the measurement at several points to check it is even.

Keep one rule in mind: an acrylic crystal is generally fitted slightly larger than its seat. Compression during fitting, followed by the material expanding, holds it in place. The margin depends on the case model; to determine it, see the measuring guide.

Diameters available

The table after this text shows the diameters available for this lipped crystal.

Available diameters