A strap is only as good as the leather it starts from. Before any cutting begins, the hide is laid flat under good light and examined across its entire surface. Full-grain leather carries the natural history of the animal — healed scars, growth marks, variations in grain density — and not all of it is suitable for a fine strap.

We are looking at grain tightness, surface consistency, and how the hide responds when flexed. A section that feels springy and resilient in the hand will behave very differently after a year of daily wear than one that feels papery or loose. We cut from the tightest, densest parts of the hide — typically the back and shoulder — and discard the flanks, which are too soft and stretchy for strap work.

The thickness also matters here. A finished strap typically measures 2.5–3.5mm at the lug end. We account for the lining layer and the folded edges when selecting the outer leather thickness — usually 1.2–1.8mm for the shell, depending on the leather type.

A strap template is prepared for the specific watch: lug width at the case end, buckle width at the tail end, overall length adjusted for the customer's wrist circumference. Unlike mass production, where a single template cuts hundreds of identical straps, each Yostrap template is drawn to the customer's confirmed measurements.

The template is traced onto the selected leather section with a silver pen, oriented so the grain runs lengthwise along the strap — this is important for how the strap flexes and resists stretching in use. The cut is made with a sharp utility knife and a steel rule in a single, controlled pass. Two passes with a dull knife leave a ragged edge that no amount of finishing will fully correct. The blade is changed frequently.

Two pieces are cut for each strap: the outer shell and the lining. The lining — typically a soft Italian calfskin — is the surface that contacts the skin, and it is chosen separately for comfort and moisture resistance.

Skiving is one of the most demanding skills in leatherwork, and one of the least visible in the finished piece. A skiving knife is used to taper the leather to near paper-thinness at the folded ends — the points where the strap wraps around the spring bar attachment loops. If the leather is left at full thickness at these fold points, the strap will be too stiff, and the fold will create an ugly ridge rather than a smooth curve.

The knife must be held at a precise, consistent angle across a stroke of 30–50mm, removing material in a single controlled shave rather than scraping. The result should be a gradient from full thickness to almost nothing — thin enough to fold cleanly, thick enough to retain structural integrity. A skive that goes too thin tears. One that is too thick creates bulk.

The outer shell and lining are joined with leather cement, applied to both flesh sides and allowed to tack before the pieces are pressed together. This is not simply gluing two flat pieces — the outer shell is first folded around the spring bar attachment points at each end, with the skived edges wrapping smoothly around the curve. Clamps hold the fold in place while the cement sets.

The alignment at this stage determines the alignment of everything that follows. If the lining is off by even half a millimetre, the stitching line will not run true, and the finished strap will look uneven. We check alignment with calipers before the cement fully cures, while there is still a small window to adjust.

Once fully set — typically several hours — the bonded strap is trimmed along the edges with a knife to bring the outer shell and lining into perfect flush alignment. Any slight overhang from the lining is pared back cleanly before edge work begins.

Before any thread is introduced, the stitch holes must be marked and punched through the assembled strap. A stitching groover scores a shallow channel along the edge of the strap — typically 2.5–3mm from the edge — which guides the pricking iron and recesses the finished thread slightly below the leather surface, protecting it from abrasion.

A pricking iron — a hardened steel tool resembling a fork with angled tines — is pressed through the leather with a mallet, creating uniformly spaced, angled holes. The angle matters: slanted holes produce a diagonal stitch pattern that is both more decorative and stronger than straight perpendicular holes. The spacing is typically 3.0–3.5mm for watch strap work, producing a clean, refined stitch line.

At the curved ends of the strap — the horns near the lug — the spacing is adjusted by eye to keep the stitch line even around the curve. This is one of those details that separates a strap made with attention from one made with routine.

Saddle stitching is the defining technique of fine leatherwork — and it is categorically different from machine stitching in the way it holds. A sewing machine uses a single thread that interlocks with itself in a chain. If one stitch breaks, the chain can unravel progressively. Saddle stitching uses two needles and one thread: each needle passes through the same hole from opposite sides, crossing the thread at every stitch. Each stitch is mechanically independent. A single break affects only that stitch — the rest of the seam remains intact.

The thread — waxed linen or polyester, 0.35–0.45mm — is cut at approximately four times the seam length. Both needles are threaded and the stitching begins from one end, with both needles crossing at each pre-punched hole. Tension is maintained by hand: firm enough to seat the thread cleanly in the stitching groove, but not so tight as to pucker the leather. The rhythm of saddle stitching is slow and deliberate. There is no shortcut.

At the end of the seam, the thread is backstitched through the last two or three holes and trimmed flush. The thread ends are sealed with a heated tool to prevent fraying.

A freshly cut and stitched strap has sharp, square edges — the natural result of a knife cut through layered leather. Left unfinished, these edges would be uncomfortable against the wrist, would fray quickly, and would look raw. Edge work transforms them into something that looks and feels intentional.

The first pass is with an edge beveler: a small chisel-like tool that removes the sharp 90-degree corner from both the top and bottom edges, leaving a small chamfer. This is done along the entire perimeter of the strap, including the curved horn sections, where the tool must pivot smoothly through the bend.

Burnishing follows. The edge is wetted lightly with water, which opens the leather fibres. A hardwood burnishing stick is pressed against the edge and worked back and forth with firm pressure — the friction generates heat, the fibres compress, and the edge begins to harden and close. Beeswax is introduced partway through, working into the compressed fibres to seal and polish. The process is repeated — wet, burnish, wax, burnish — until the edge has a smooth, hard finish that catches the light and resists fraying. Done well, a burnished edge is indistinguishable in texture from polished bone.

The adjustment holes are punched with a rotary punch set to a diameter appropriate for the buckle tongue. Their positions are marked with calipers to the customer's wrist circumference — typically five holes at 10mm spacing, positioned so the middle hole corresponds to the optimal buckle position for that wrist size.

After punching, the inside of each hole is lightly burnished with a small cylindrical tool to smooth the leather fibres around the opening — this prevents fraying at the hole edges, which are a common failure point on cheaper straps. The buckle is then set at the tail end, its pin threaded through the fold, the keeper loops assembled and positioned.

Where the order calls for a lug adapter — required for watches with curved or integrated lug designs — the adapter is fitted at this stage and secured as part of the strap assembly, not added as a separate component after the fact.

Before the strap leaves the bench, it receives a light application of leather conditioner — neatsfoot oil or a similar penetrating oil — worked into the grain side by hand. This replaces any natural oils lost during the tanning and working process, and begins the strap's relationship with the leather in a healthy state. A strap that is conditioned before it is first worn breaks in more evenly and develops a more even patina.

Final inspection is methodical: every stitch is examined for consistent tension, both edges are checked for completeness of burnish, the holes are checked for alignment, the hardware is tested for secure fitting, and the overall silhouette is laid against the template to confirm dimensional accuracy. If anything is not right, it goes back to the relevant step. It does not ship.