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55 50 -- If the hex recesses in the screwheads are still hexagonal and if the tapped holes are in a beefy piece, a hit-it-with-a-hammer "hand impact wrench" could work magic. Otherwise, I'll suggest that you drill off the heads of the screws, using a drill that's the same size as the Major Diameter of the thread. Once the heads are gone, remove the knife before hitting the screw shanks with a dose of penetrating oil and a dose of hammer-tapping if the screw shanks aren't already loose in their holes. The flanks of the threads on the screws have been pulled right up to the flanks of the threads in the tapped holes on the to-knife side, leaving all the clearance on the away-from-knife side. With a tiny bit of good luck, the penetrant will flow through the clearance, and tapping will break the flank-to-flank adhesion so that the stubs can be unwound easily. If your luck is not-so-good and the screw stubs won't come out, make yourself a simple drill guide and drill them out using a drill that's appropriate for tapping that particular thread size. You want to remove all of the "core", leaving only the male thread as a helix of material wound into the internal threads. Then pick that helix out with a scriber if you can, otherwise cut it out with a tap. John
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