Probably these informations are not sensational but we found ourself new for us.Before we hasn't any experience in leatherworks!
During stiching sole with upper it is necessery to touch a bee wax by needle point very frequently(NOT syntetic parafine),to reduce friction for thread and needle.
BEFORE turning off the shoe SOAK shoe in the water for few hours because it could be danger for sole(You can breake it easy if the sole is proper hardness and quality).That is not necessary if sole was made from rawhide.
During making the last NEVER create a bit bigger then planned(just in case).If not,you will get monster but not nice shoe.
Making the last is not really difficult.One pair of lasts took me abt.3 hours total time(and a lot of wooden dust in the air).Last was cutted by jigsaw wertically and horizontally and by the and ,by flex grindner( maybe is too modern but works faster)and sandpaper disc(grain 36) .At the and,finished by hand.
DO NOT stretch too much the upper before tacking to the last.This could be source of serious problems,when do you need to remove the last from shoe:-( .Also ready shoe,if becomes wet ,may can be smaller after drying :-(((
Linen thread have to be waxed well and could be warmed in gas lighter for a second. It will allow to penetrate thread by beewax. Than wax thread again.
The most important advice:The last should be finished very well by fine sand paper(i.e. 400). Also the last should be waxed or covered by varnish. It will make surface of the last glossy. Omitting this can be source of serious problems during painfulls trials in removal of the last from shoe. I dicover it TOO LATE :-( .especially if we are making shoe for high foot.
During sewing sole to the upper do not remove fastening pins from the last.After 10 or 20 stiches-max,you will get bent sole and upper in different posinion as planned before!Each stich pulling upper more and more downward.Finally the opposite side of the shoe doesn't fit properly to the sole. The shoe is not straight and looks terrible.Also do not cut upper before is sewed completely around of the sole.
From my experience appears that first should be needle passing through the hole from sole side towards upper. Than second needle going out form sloe.Upper is more soft than sole and more difficult is to find hole in upper.
After production of few pairs of shoes i know why famous Polish ancient shoemaker Jan Kiliński was able to fight by his sable so well.;-).
Womens shoes XII/XV th century,drying on the last,during creation process
Viking shoes made on the last just before reverting onto right side.