The taper you feel at the edge of a good strap isn't decorative. It's a hand-cut bevel that makes the seam sit flush.
Machine seams unravel when one thread breaks. A saddle stitch never can โ that's the difference between a strap you replace and one you inherit.
Before a strap is cut, the leather is judged by feel. Here's what the workshop notices โ the give of the grain, the pull of the temper, the whisper of the flesh side.
