With their thin stock blades beveled at 30 degrees, when you close the mouth opening on a Stanley Bailey design plane then the frog does do not support the blade all the way to the heel. With a thicker blade the frog might support to the heel as the contact height of the blade would increased. For my Stanley plane with a 0.091 thick sole behind the mouth opening I would need a blade at least 0.175" thick to have support to the heel with zero depth of cut. Maybe you could modify the frog by epoxying a piece of metal to extend the bed all the way to the sole. The mouth would have to be filed open to accommodate this new piece. This would be like Lee Valley's Veritas bench planes but cheeper. I want to try this if I work up the guts to do it. Alternatively you could use thin shims the same size as the blade to move the blade forward in the body to close up the mouth.
Read David Finck's Making & Mastering Wood Planes. Learn how to make Krenov style hand planes and a whole lot more. A great introduction to woodworking
Read James Krenov's The Fine Art of Cabinetmaking. In one chapter the originator of The Krenov Plane describes how he makes them. Throughout the book he conveys his passion for wood and woodworking.
Read Wooden Planes and How to Make Them by Daved G. Perch and Robert S. Lee published by Algrove Publishing and available through Lee Valley. Lee. Describes make more types of wooden planes.
Read Jim Kingshott's Making & Modifying Woodworking Tools. It describes how to make cast metal planes and infill planes with double dovetails joining the sides and sole. If you click on his name you will visit a site that contains errata for the book.
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