Once the most prominent and experienced makers of milling machine in the USA - and in post WW2 years with factories in England and Japan - the Kearney & Trecker Company was founded in 1898 by Edward J. Kearney (1868 - 1934) and Theodore Trecker (1868 - 1955). Despite an early lead, from 1958, in NC control, the Company lost its was in the 1980s and, having been overtaken by Japanese and German competition, was forced to close in 1993. If you have a K & T machine and would like to know its age, a list of Serial numbers can be found here
Manufactured in both the United States and England, the Kearney & Trecker Model 2D rotary head milling machine is thought to have been unique in its ability to produce, in metal, the sort of geometric shapes produced by a draftsman using ordinary drafting instruments such as a T square, set square, compass and protractor.
To achieve this, the 2D copied with its longitudinal table travel the horizontal line drawn with a T square; its traverse (in-and-and-out) table travel replicated the line drawn with a set square; the head's unique rotary motion replicated the arcs, radii and circles produced with a protractor and the angular motion of the spindle slide - when combined with the angular setting of the rotary head - copied the lines developed at any angle by a protractor. In addition, K & T offered a cherrying attachment, this acting as an auxiliary rotary head at right angles to the previous plane of operation and so allowing the development of spherical shapes.
See more on cherrying heads here: https://www.lathes.co.uk/everede/ and https://www.lathes.co.uk/armag/ and https://www.lathes.co.uk/riva/