I have an Inca 410 jointer/planer and I would like an extra set of
knives. They are no longer made, and are a strange size (8-5/8" by 1"
by 3/32" thick). I haven't been able to find anything compatible,
McMaster sells D2 tool steel that is 3/32" thick by 1" wide by 18" long
for about $28. They say it is "Wear-Resistant Air-Hardened D2 Tool
Steel." Hardness is specified as "B89-B102" with a maximum attainable
hardness of C62-C65. I have found a local sharpening shop that will
cut it into two knives and sharpen them for less than $20.
My question is whether the initial B89-B102 hardness is enough, or if
they would require additional hardening. If B89-B102 is enough, then
$50 doesn't seem too bad for a custom set of knives. But if additional
hardening is required, I imagine that would be expensive and extra
McMaster also have a 4140/4142 steel that they say is hardened to
C28-C32. However, I have seen D2 mentioned for planer knives but never
4140/4142, so I don't know if this 4140 steel is appropriate?