This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
From what has been said respecting the structure of wood it will be seen that wood can be chosen to make lasts so that the greater shrinkage may be either in the last's height or width. This is an important point, because, if the wood should shrink much, odd lasts would be the result, whereas, if properly mated, the shrinkage could be made good by "fittings."
Bark-bottomed lasts are those which are selected so that the bottoms face the bark, and bark sides are those that are cut from the wood so that the "height" of the last runs parallel to the bark. Bark sides are usually preferred, because any shrinkage that takes place may be remedied by using a fitting on the top of the last. Figs. 91, 92, 93 show bark-sided lasts, and Figs. 90, 94 bark-bottomed lasts.
Chopping or sawing the Block is the next process performed. The older plan was to chop the block with the axe, while latterly it is sawn with the circular saw into something like the shape required. This "squaring" of the block greatly facilitates the after work of knifing (Fig. 82).
Knifing the block is the next stage. It is done with a bench knife that consists of a blade about 14 ins. long. A series of well-directed cuts from this knife gradually diminishing in size reduces the block to the rough outline of the last. During the knifing constant reference has to be made to the insole shape or model, and the measuring tape has to be frequently applied to the evolving last. The roughed piece is now ready to have the block cut.
The block is sawn down according to the kind of work required to be made upon the last, or the taste of the last-maker.
The Completing Processes are drilling the holes to allow the block and last to be drawn respectively from the boot, rasping, scraping, and finishing. These operations require attention, as they add much to the shape, finish, and after use of the last.