Reply To: Plane blade hollowed out in center

So, I did some exploring with feeler gauges. Everything is flat side to side within 0.001″ except for one plate (superfine) that had a hump across the width, but the hump was only 0.0015″. Two of the plates were flat to <0.001″ end to end, one had 0.0015″ hollow end to end, and one had a fall off of 0.002″ at one end (not side to side).

Thus, the plates are all mechanically fat in the dimension that matters. Since the plates are 10 years old, though, it may be that the edges are less abrasive than the center, e.g., from flattening the backs of tools.

One thing I did find, though, is that the cheap square I was using to assess the blade is *not* straight and explains some or even most of the hollow. So, much of this is a measurement phantom.