Whether you're ordering your first leather strap or commissioning a bespoke piece, knowing the right words makes the process faster and the result better. At JackCoHenry, we use most of them daily. This glossary covers every term you're likely to encounter — from lug width to edge bevelling.
Fit, Dimensions and Strap Construction
Lug Width — The internal gap between the two lugs on your watch case, measured in millimetres. The lug width determines which strap width will seat correctly. Always match strap lug width to your watch's lug width exactly.
Taper — The narrowing of the strap from the lug end to the buckle end. A 20/18mm strap is 20mm at the lug and 18mm at the buckle. A stronger taper (e.g. 22/16mm) gives a more elegant profile; a mild taper (22/20mm) looks more robust.
Long Piece — The longer half of the strap — the piece that passes through the buckle. Typically 100–120mm depending on size.
Short Piece — The shorter half, which carries the buckle. Typically 65–80mm. The short piece length determines where the buckle sits on your wrist.
Total Length — Long piece + short piece combined. A standard Medium strap is 185mm total (110 + 75).
Wearing Length — The effective length from lug to the hole you actually use. Used for precision sizing when ordering bespoke.
Lug Hole / Lug Bar Hole — The small recess inside the watch lug where the spring bar seats. The bar tip must click into this hole to hold the strap securely.
Spring Bar — A small spring-loaded metal pin that sits inside the lug holes and holds the strap to the watch case. Spring bars are measured by length (matching lug width) and diameter (typically 1.5mm or 1.8mm).
Spring Bar Tool — A tool with a forked tip used to compress the spring bar, releasing it from the lug hole. Essential for swapping straps safely.
Quick-Release Spring Bar — A modified spring bar with a small lever on one end, allowing strap removal without a tool. Common on pilot-style watches.
Straight End — A strap end with a flat, perpendicular cut. Fits most watches with standard parallel lugs.
Curved End — A strap end shaped to follow the contour of a specific watch case. Needed for watches with downward-angled lugs — e.g. F.P. Journe, H. Moser & Cie, Ming.
Pad / Raised Centre — A thickened central section along the strap. Adds comfort against the wrist and gives a sportier profile common on vintage-inspired straps.
Liner / Backing — The underside layer of the strap, which contacts the wrist. Typically a softer leather than the outer face. Common linings: suede calf, Chevre sully, nubuck.
Layers — Most quality straps are multi-layered: a face leather, a reinforcing mid-layer, and a lining. Stitched through all layers at the perimeter.
Hardware
Tang Buckle (Pin Buckle) — The standard frame-and-pin closure. A metal frame with a centre bar; the pin inserts through a hole in the strap to fasten. Simple, reliable, universally repairable.
Deployant Clasp (Folding Clasp) — A folding closure that attaches to the strap tail and folds open for fitting. Reduces strap flex and leather wear. Common on higher-end straps and sports watches.
Buckle Width — The width of the buckle opening, which should match the strap's taper end (not the lug end). Typically 2mm narrower than lug width — a 20mm lug strap usually takes an 18mm buckle.
Keeper (Loop) — The small loop that holds the strap tail after buckling. Most straps have one fixed keeper (attached to the strap body) and one floating keeper (slides freely along the tail).
Fixed Keeper — The keeper stitched or permanently attached to the strap near the buckle. Holds the short end of the strap in place.
Floating Keeper — A loose loop that slides along the strap tail to secure the excess after the buckle is fastened.
Leather Terms
Grain — The natural surface texture of leather. Full-grain leather uses the outermost layer of the hide with the natural grain pattern intact — the most durable and characterful.
Full-Grain — The highest quality leather grade. The natural grain is preserved, not sanded or corrected. Full-grain leather develops a patina and improves with age.
Corrected Grain — Leather that has been sanded and given an artificial grain pattern. More uniform in appearance but less character and shorter lifespan than full-grain.
Vegetable-Tanned — Leather tanned using plant-derived tannins over a slow process (weeks to months). Develops a rich patina with age. Examples: Buttero, Pueblo, Badalassi Carlo Wax.
Chrome-Tanned — Leather tanned using chromium salts, much faster than vegetable tanning. Softer and more uniform from the outset. Chromexcel is a notable example.
Pull-Up Leather — A heavily oiled or waxed leather that shows a visible lighter "pull-up" effect when stretched or folded. Develops a distinctive patina. Examples: Chromexcel, Badalassi Carlo Wax.
Shell Cordovan — A dense, non-porous leather from a specific muscle layer on the hindquarters of a horse. Develops a mirror-like patina with wear. Sought by collectors for its longevity.
Patina — The change in surface character that leather develops with use — subtle colour deepening, sheen development, and visible wear marks. Considered desirable on quality leather.
Finishing
Edge Painting — A coloured paint or dye applied to the cut edges of the strap to seal and finish them. Multiple coats are applied and burnished. A well-painted edge is a mark of quality.
Edge Bevelling — Chamfering the sharp corners of the leather edge before painting, giving a rounded, softened profile. Done by hand with a slicker or bevelling tool.
Burnishing — Rubbing the edge of the leather to compact the fibres and create a smooth, polished finish. Used on natural or raw edges instead of paint.
Saddle Stitching — A hand-stitching technique using two needles and a single thread passed in opposite directions through each hole. Stronger than machine stitching — if one stitch breaks, the rest hold.
Stitching Pitch — The spacing between stitches, usually measured in stitches per centimetre. Tighter pitch looks more refined; wider pitch is faster and has a sportier character.
Contrast Stitching — Thread colour that differs visibly from the leather — for example, cream thread on dark brown leather. Adds visual detail at close range.
At JackCoHenry, we mainly use edge painting, saddle stitching, and a 2.27mm stitching pitch to achieve a clean, refined, and durable finish across our watch straps.
Frequently Asked Questions
Q. What is the most important measurement when ordering a strap?
Lug width. Everything else can be adjusted or approximated, but if the lug width doesn't match your watch, the strap won't fit at all.
Q. What's the difference between a deployant clasp and a tang buckle?
A tang buckle is the classic frame-and-pin closure. A deployant folds open rather than threading through a hole — it distributes stress more evenly and tends to extend the life of the strap's hole area. Deployants are harder to fit and remove but more secure in daily wear.
Q. What does "full-grain" mean and why does it matter?
Full-grain leather keeps the outermost layer of the hide intact — the densest, most durable, and most characterful part. Corrected-grain leather has been sanded to remove imperfections, which also removes the natural structure. Full-grain develops patina; corrected grain tends to peel over time.
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→ Watch Strap 101: A Beginner's Guide