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The Encyclopedia of Horology

Component record · Case

Lug

Verified

One of a pair (or two pairs) of projections extending from a wristwatch case, drilled or notched to accept the spring bars that attach a strap or bracelet.

What it does

Provides the structural attachment points connecting the case to its strap or bracelet, and contributes significantly to a watch's proportions and wrist fit.

How it works

Lugs are typically cast or machined as an integral part of the case rather than a separate fitted component, drilled through to accept spring bars.

Lug width (the distance between the inner faces of opposing lugs) determines compatible strap sizes and is a key case specification.

Lug shape and angle (straight, downturned, or 'bombé') significantly affect how a watch sits on the wrist and is a major element of case design and period style.

Evolution

Early wristwatches often used simple wire lugs soldered to a converted pocket-watch case; integral, robust cast or machined lugs became standard as wristwatches matured into a purpose-built category through the 20th century.

Known variations

  • Straight lugs
  • Downturned (curved) lugs for wrist fit
  • Wire lugs, characteristic of early wristwatch conversions

Identification for collectors

  • The projecting arms of the case where the strap attaches, whose shape and spacing are useful dating and identification clues

Common failure modes

  • Cracked or bent lugs from impact
  • Worn or elongated spring-bar holes from repeated strap changes

Photographs

Lugh spear Millar
Lugh spear Millar — Harold Robert Millar, Public domain. Wikimedia Commons file page
Lug gutshaus
Lug gutshaus — Z thomas, CC BY 3.0. Wikimedia Commons file page
Lug (Pfalz)
Lug (Pfalz) — Urlaubsregion Hauenstein, CC BY 2.0. Wikimedia Commons file page
Lug (Bronkow), Landschaft
Lug (Bronkow), Landschaft — Dguendel, CC BY 4.0. Wikimedia Commons file page

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. de Carle, D., Watch and Clock Encyclopedia

Where sources disagree, the disagreement is stated rather than resolved silently.