Originally Posted by ThunderMarch @DWFII
Could I just ask, I understand what a holdfast is, but what is a "feather" and what does it do?
Around the forepart of most lasts there is an edge...a "corner", if you will. Often times it will discontinue in the waist and then around the base of the heel this edge begins again. That edge / corner is known as the "feather edge."
It really has no known physiological function simply because feet themselves do not have and edge, although there are highly respected lasts from the first part of the 20th century (maybe even older but mine are from the '30's, I think) that have a rounded bottom more like a foot, esp. in the heel seat area.
In any case, the only function of the feather edge is that after the insole has been blocked to the bottom of the last and allowed to dry, it is trimmed to that edge. I have heard shoemakers call the edge of the insole the "feather" on occasion but I suspect that is a pretty old usage.
When the trimmed insole is prepared for inseaming, a "rabbet" or notch is cut into the edge of the insole. This notch is commonly called the "feather" although some may call it the "outside channel" (a usage that I suspect is derived from the original GY welting process). The feather allows the upper and the welt to be drawn under the edge of the insole slightly as the inseaming thread is pulled tight, to protect it.
So, the inseaming thread goes from the inside channel through the holdfast, out the feather, through the lining and upper, and out the welt.edited for punctuation and clarityEdited by DWFII - 2/8/16 at 7:32pm