Looking inside … the “engineering works”
The image above and on the right shows a shoe on the last, with the upper nailed in place and the welt halfway stitched on (you can see one end of the welt hanging off in the image on the the right). You can also see the rib, cemented to the insole, to which the welt is stitched in the centre. The rib is the white ridge around the greenish insole in the next image .
The welt is ultimately stitched to the outsole, once the spare upper leather has been trimmed off. This stitching forms the very strong -but-flexible bond between upper and sole that is characteristic of a welted shoe. Naturally, the welt is a piece of thick, strong leather, so it creates a gap between insole and outsole – which must be filled as shown on the left. In this example, the filling is another natural material … cork … with a shank (in this case, a metal “plank”) that stops the sole area just in front of the heel from being floppy. You can also see that the welt has been sewn down all the way round ,and the spare upper leather trimmed off – so it is ready to have the sole sewn on to the welt or cemented in place. Add a heel … and we have us a shoe