This company made hand saw sharpening and retoothing equipment, and patented saw setters. There are several Google Books snippet views from 1944 indicating that they introduced their retoother then. The earliest ad found was Jan. 1946, and advertising continued into the early 1960s.

The company was founded by Burr Nathan Engle (1888-1950), and also included his wife Inga M. (Anderson) Engle (1891-1981) and son John B. Engle (1921-2002). Their first patent was for a retoothing machine, which the patent called an "indenting device," application filed June 13, 1944 by Inga Engle and also assigned to her. It was granted Sep. 17, 1946, but the sources indicate that they had begun manufacturing in 1944.

Of the six patents by Burr Engle, John Engle, or both, none are for a saw filer or sharpener. The only available printed documentation for these machines is their advertising. A 1949 ad shows a conventional fractional horsepower motor driving a sealed gearbox which in turn moves a sliding arm holding the file. This assemblage is on an open frame that can pivot, and it is mounted on a lower frame that clamps the saw and rides on a track which provides indexing. The illustration doesn't show a stand or bench, so it's unclear whether the lower frame or the track is fixed.

A video of a Burr retoother is on YouTube.

• Information from an advertisement in the July 1952 Popular Science magazine, page 247.
• Address: 8933 Venice Blvd, Los Angeles 34, California.
• Catalog of Copyright Entries: Third Series, Vol. 2, Parts 7-11A, No. 1, 1948, pg. 15. Burr Manufacturing Co., a partnership, John Engle and Burr Engle.
• The Burr retoother manual is from an abandoned blog from 2008, sawfiler.blogspot.com, and was credited to Mark Harrell.