For the joining of multiple layers of heavy leather, as with this axe sheath, I like my stitching awl. It's a heavy duty little tool!
The waxed thread feeds from a center-mounted spool through a groove in the needle.
It's a push-pull operation; push the needle through a prepunched hole, pull back to create a loop, then pass thread through the loop on the other side of the project and pull the needle out. This creates a strong, tight and durable lock-stitch.
When I put something together, I intend for it to stay together!
Though there are certainly machines that could handle the thickness, the precision and control of hand-stitching creates a finished result that I consider superior.
There are many other methods of joining leather, including decorative lacing. We'll cover those in a future post!