... today's post deals with
countersinks that are not integral with a bit, but rather,
attach to a bit for boring and countersinking holes for the
insertion of screws.
The first photo illustrates an
assemblage of this tool type made before 1900 for use in a
brace. All are extremely rare and I considered it a milestone
day when I found each one of these tools. They are explained in
captions with each photo.
This photo illustrates an
assemblage of countersink devices for boring screw pilot holes.
These attachments allow an advantage of boring screw pilot holes
of various depths depending where they are attached to bits
along their lengths.
Both of these specimens are British in origin
and "sandwich" over a bit shank.
All of these countersink attachments were issued U.S. Patents.
The specimen on the left is British in origin. Notable is the
second specimen from the left. The two specimens on the right
are made of cast iron.