Thread and sewing plays a pivotal part in any leather product.
We use Ritza 25 (also known as "Tiger") thread imported from Danish company Julius Koch. This thread is prized amongst other leatherworkers because it's specifically designed and spun for leather products. The polyester thread is flat and braided which makes it very durable and built for a lifetime of rigorous use.
However, it's not just the high-quality of material we consider. If thread is sewn improperly, it will eventually unravel and ruin the leather product.
Machine sewing uses an under-deck mechanism that traps the thread from the needle above, forms a loop, and binds the layers of leather. If the thread is ever cut or frayed, it will unravel since it's woven into itself. That means, if one link in the chain breaks the entire stitch fails. Here's a visual example of machine ("lock stitch") versus hand:
All our goods are sewn by hand using the "saddle" stitch method. When we hand-stitch, we use two needles that pass through the same hole on opposite sides. This method doubles the strength of machine stitch. Since each needle passes through the same hole without friction, it binds using a net of thread that clings to the leather. Conversely, machine-stitching doesn't bind to the leather, it binds to itself when it loops. - this method can be fine for fabric, but we want our leather products to last a lifetime.
Here's a great YouTube video on saddle stitching in detail by Nigel Armitage, It's much easier to see saddle-stitching than describe it. Once you watch a master like Nigel work, you begin to appreciate sewing as an art. If you're as fascinated by hand-sewing as we are, it's worth a watch.