Hand Tools Archive

My favorite durability claim so far...

david weaver

Looking for an academy saw works blade yesterday as I'm fairly sure the chinese blade is a good blade, but i don't know for sure that it meets is hardness spec and it may not give an accurate view of what M2 is capable of.

I never found a hobart or ASW blade, but I again found people trying to push a $100 kunz blade (that always pisses me off) and then this page - claim excerpted here.

"You can expect 20 to 40 times the interval between sharpenings when upgrading to High Speed Steel "

The listing goes on to explain the virtues of grinding hot and not worrying about it, but there's a reality to that - you'll burn your fingers on the iron. HSS irons don't spark much and they do seem to generate a lot more heat on the wheel (i'm using CBN, so it's not like I'm at the high end of the heat spectrum, either - I can still brown an edge on CBN if I feel like it, but I either have to set the iron down and something else or lay it on top of an oilstone for a little bit and let the stone soak some of the heat out of it)'

"The modified blade may require an upgrade of sharpening equipment - Japanese Waterstones are recommended."

(I'm guessing they sell waterstones, and probably not much loose diamond. I can sharpen HSS on oilstones now, as bill points out, not to its max potential, but the chinese iron in this test is something I sharpen regularly with oilstones. Something like soft waterstones would be a mistake with HSS irons)

Then, since the bit is small, they say this at the end:
"Remember that tool steel plane blades are only tip hardened and when they are worn down within about 10 to 12mm of the back iron slot the steel will not hold an edge."

Maybe that's true for new irons. I've got a lot of older irons that I've gotten in planes that were worn almost to the slot, and they still work fine.

LN told George that they weren't hardening the full length of their water hardening steel irons, but with their tendency to warp, it's easy to understand why they'd do that. I would expect that while the slots on a lot of new irons can be filed a little bit to fit a plane, I'd sure hope that they were hardened to the slot on the bit end.

20 to 40 times, though...wow.

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