Bulldozer blade contour gauge.
Fullsize image: https://diqn32j8nouaz.cloudfront.net...e_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...tour_gauge.jpg
Previously:
https://www.homemadetools.net/forum/...5477#post81955
https://www.homemadetools.net/forum/...405#post131512
https://www.homemadetools.net/forum/...948#post133757
