A leather awl opens or eases a stitch hole so the needle and thread can pass through with slight resistance. Modern stitching irons are normally designed to punch fully through the leather. If you prefer the traditional method, the iron can mark the positions and the awl can open each hole as you stitch. I normally punch through with my irons but still keep an awl nearby for tight holes, thicker thread and backstitching.
Traditional pricking irons mark spacing for an awl, while modern through-punch irons and stitching chisels can form holes directly. Learn when each method applies.
A pricking iron sets the stitch spacing and hole profile for all hand stitching. French-style irons produce narrow, slanted slits. Diamond-style irons produce diamond-shaped holes. The finished appearance also depends on spacing, thread, leather and stitching technique. Spacing — typically 3mm to 4mm for most hand leatherwork — should match the leather weight and thread size.