... there were many types that were made for use in a brace.
Those in the first photo are my favorite type and I use them
frequently when I am inserting screws in a project. Not only do
they bore pilot holes for screws, they also create countersinks
for screw heads. I have never found a set of this type of pilot
This photo shows a "set" of screw pilot drills that I assembled
for use in a brace.
The assemblage you see in the photo was found over the years a
single bit at a time. I find I have complete control of boring a
pilot hole and countersinking it to accommodate a screw head
because I can turn the bit slowly with a brace unlike modern
pilot drills driven by a cordless or corded power drill. If you
happen to locate some of these drills in your search for old
tools, I highly recommend you get them and give them a try.
Today I selected a gunmetal Horton brace to drill screw pilot
I use an awl to indent the spot for a screw so the pilot bit can
precisely at that exact place. The wood is local sassafras.