Welting

At last (sic) the upper is sewn on to the last.

At last (sic) the upper is sewn on to the last.

Welt sewn in

This is a key step in creating a Goodyear welted shoe. Before the welt can be sewn on, excess leather from the upper is trimmed off. The welt is a thick strip of tough leather (here black) that is first sewn firmly onto the rib. You can still see the rib here as a white ridge with black stitches anchoring it securely to the welt. In all of these stitching steps, strong waxed thread is used to make the shoe as waterproof as is possible.

Welt trimmed and beaten This all leaves more spare upper leather to be trimmed off, without, of course, trimming too close to the welt stitching. The welt is then bashed flat!  Nonetheless, you can see that the welt is now raised above the outsole surface and a sole can't be attached without first filling the gap.

The welt is beaten flat, to avoid unsightly and uncomfortable ridges.

Welt trimmed and beaten

This all leaves more spare upper leather to be trimmed off, without, of course, trimming too close to the welt stitching. The welt is then bashed flat! Nonetheless, you can see that the welt now forms a raised border around the outsole surface and a sole therefore can’t be attached without first filling the gap.