By Gage Tool Co. New Jersey (Pre Stanley)

This is a very nice example of the pre 1919 Gage No.4 plane. It is 10 inches long with a 2 inch cutter. The front knob is black painted hardwood. The tote is a dark stained hardwood and is fastened to a cast plate which is screwed to the rear of the plane. Gage attached a small metal plate to the top of the rear handle to try to prevent breakage to the handle tip.
The plane was patented by David Bridges in 1883, and improved by Bridges and J.P. Gage in 1885.
They were manufactured by the Gage Tool Company till 1919. John Porcius Gage formed this company and owned it until 1917.
In 1919 it was sold to Stanley Rule & Level Co. who continued to use its name and manufacture these planes until 1935.
Stanley introduced a new numbering system to the 8 models of this plane starting at G22 through to G36.
The toe is stamped Gage Tool Co. Vineland, N.J.
How the Self Setting patent works

The metal mouth is incorporated in the frog system.
Here you see the frog screwed in position to the beech body.
The plate on the blade in the image(above), is used to hold a special casting on the other side of the blade (below) and once set, the blade can easily be removed for honing and replaced again in the same position as before, leaving no need for re-setting.
The notch in the casting, slots into this part of the adjuster screw. (pic below)