A wing divider is used to press a shallow groove onto the leather surface. The standard stitch pitch is 2.7–3.0mm, set 1.8–2.0mm from the edge. Lines must be perfectly straight with no rebound. A 45° slant awl is used to enter the leather diagonally. The hole is shaped like a micro-funnel—wider on the outside and narrower on the inside—to prevent the thread from snapping. At handle attachments and flap edges, “teardrop” holes sharp at the top and rounded at the bottom are punched. This is a signature Kelly detail that ensures smooth, wrinkle-free stitching at the corners.

Original French waxed linen thread is used. Coated in beeswax, it is wear-resistant, waterproof, and develops a patina over time. Two needles are threaded at each end. Both needles pass through the same hole from opposite sides, creating a 45° interlocking stitch. The front displays a continuous “slanted wave” pattern, while the back shows a straight double line. Each stitch bears its own tension; even if one thread breaks, the rest of the seam remains secure and will not unravel. After each stitch, the thread is pulled diagonally to embed it into the leather surface, ensuring it sits flush without protruding or sinking.

Standard teardrop holes are punched where the handle meets the body, with the point facing up and the curve facing down in perfect symmetry. The stitching follows a “left-low, right-high” 5° slant, with pressed imprints to fit the curve of the handle. For Sellier styles, the stitching is exposed. Holes must be equidistant and of equal depth. Corner needles enter at an angle for a smooth flow without overlapping. Stitch density is 8–9 stitches per cm on straight sections, increasing to 10 stitches per cm at corners. Standard three-stitch backtacking, slanted left-to-high, ensuring the curve connects naturally to the body without abrupt pivot points.

Sellier with external stitching common in Epsom leather features exposed stitches and precisely symmetrical holes, creating a structured, sharp-edged look. Punching is shallower, with stitches embedded about 0.3mm into the leather for a clean aesthetic. Retourne with internal stitching common in Togo leather keeps stitches hidden on the inside. Holes are slightly deeper and spaced wider apart, giving the bag a softer, vintage feel. There are no exposed stitches on the edges, and the leather at the punch sites turns inward naturally for a supple touch.