Rare Antique Early American Large Wooden Tool, probably Cabinetmaker's Square or Gauge, probably 1780's-1830's

This rare and unusual wooden square was used as a specialized guide for cutting wood, veneer, leather, paper or other thin material by a craftsman in New England/ Northeast US probably about 1780-1840. 

The tall bar is probably tulip poplar and short base bar appears to be walnut and is molded on both sides like 18th-century planes.  The small protruding tab would act to hold whatever was being worked firmly flat and square and all cutting appears to have been down along the outside of the tall bar where there is wear and the deep patina of the piece is effectively worn off along that one edge only.  Piece has an original hole for hanging near the top of the tall bar.  

Feel free to message me through eBay Messages if you have an alternative theory on the use of this article.

Dimensions:  32-7/8" tall x 7-1/16" wide, plane-like base: 2-5/8" tall x 6-1/2" wide, tab protrudes 1/2"

Condition:  No losses or damage, deep original patina, some spots of white paint residue.