When my Dad (a serious pack rat) passed away a few years ago, among his tools I found a number of antique measuring and layout tools, as well as a few journeyman projects. This example is my favorite and I wondered if anyone else has encountered a similar example.
The tool is some form of early caliper. Stamped on the rear is a name and patent date, "A. E. Whitmore", 1869... see the last photo. A google search reveals a Remington firearms designer as being the likely creator.
Photo 1 - the caliper is of high quality and has some of the finest convex instrument knurling that I have ever seen. The jaw to the right is moveable, while the jaw to the left has a very short range of 0.025", actuated via the knurled adjustment on the left. To use the caliper, the right jaw is positioned first, and the left jaw then does the final, finer movement. The jaws themselves are hemispheres for internal (bores) and external measurement. The jaws are stepped, with the major OD being 0.400", and at the tip, 0.200"
Photo 2 - On the spine of the body are a series of precision notches. When the right jaw is positioned and then tightened, that jaw is locked in place via these notches, spaced every 0.025". Note the micrometer barrel on the left jaw.
Photo 3 - The name and patent date.
I was excited to find that "A. E. Whitmore" was an early gunsmith. 1869 was in the heart of the era when firearms were beginning to be mass-produced with interchangeable parts, rather than hand-fitted. Like many old measuring tools, this caliper has a fit and finish, and overall feel, that is very pleasing.
Again, has anyone seen anything similar, or does anyone know more about Whitmore?