Bill Tindall, E.Tn.
Objective: Determine how much force is required to flex a plane 0.0015"

Experimental: Planes are a Bedrock 505 and a Stanley #7. Two 90 pound rail sections, dial indicator and assortment of 2.5 and 5 pound lead bars. Plane is bridged between the rails. Lead weight added above mouth. Flex measured by dial indicator.

Results and discussion: Assume all the flex is from the plane and none from 90# rail sections. It took 7 pounds of force to flex the #7 0.0015" and 5# to flex the 605 this amount. Error bars estimated to be +/- 1 pound.

Conclusions: none. I don' t know enough about how people plane to know how much weight they apply and more important I don't know how much force is applied by the blade sucking the plane bottom to the board. From Kato's work this value would be 1 to 3 pounds for a 1" wide shaving.