Hand Tools Archive

Subject:
disagree that chisels predict planing
Response To:
A comment on steels. ()

Bill Tindall, E.Tn.
intended to look at wear in chisels when paring. It is, however, really not that different from planing ...

While this well done study provided guidance on chisel selection for the tasks used, I don't think the results will predict the performance of these steels in a plane blade.

Steel has three fundamental properties- hardness, toughness and abrasion resistance. For a shaving lifter David's work is suggesting that abrasion resistance will be the primary factor that determines edge life. It took hundreds of feet of blade passing through wood to begin to separate the performance of the steels being tested.

Chisel edges fail at least an order of magnitude quicker when judged by inches of wood they pass through when chopped. Clearly a chisel edge is failing by a mechanism other then abrasion. The work I did suggests failure is by some combination of deformation and/or micro chipping which in turn suggest that selection of chisel steel becomes a balance of hardness and toughness, properties that unfortunately negatively correlate. It also suggests that technique will have a great bearing on chisel edge failure as Warren has stated.

This hypothesis is confirmed by the steels that have proven to make good chisels. PMV11, 3V and the Japanese steel you found superior all exhibit exceptional toughness at high hardness. Most agree that carbon steel makes a better chisel than A2 and the hardness/toughness values are consistent with this finding.

On the technique issue, Alan Batty provided information on how an English furniture factory made drawers in the early 1950's. The production quota was astonishing, 6 drawers a day, to someone that takes a day to make a drawer. They were chiseling oak drawer sides with chisel steel of that day. My notes are unclear whether they sharpened once a day or twice. Importantly(I think), the dovetails were pared, never chopped. Paring will stress the blade tip more like planing.

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