A2 at 64RC for scraper blade

N

Nate Johnson Arts

Joined
Oct 24, 2022
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Hi everyone, I make and sell a scraper blade for hide tanning. I'm currently using A2 steel with a 45 degree single bevel. The bit is slightly rounded. I'm considering jumping up to 64rc to maximize wear resistance. A great way to dull a blade is to scrape it against a thick dry stretched moose hide. Toughness isn't an issue for this application, just edge holding. Wondering if people have experience working with steel hardened that much (I don't), and if there's any problems foreseen outside of more difficulty sharpening and potential brittleness of edge when it gets inevitably dropped. I'd like to stick with A2 for affordability sake, rather than jumping up to D2, so I'm just looking to get everything I can out of A2. Blades currently at 60rc professionally treated including cryo. Thanks.
 
If you're not familiar, knife steel nerds is a great resource. https://knifesteelnerds.com/2019/04/22/a2-steel-history-and-properties/

From this, jumping from 60 to 64 Rc drops your toughness from approximately 15 to 5 ft-lbs. That is quite substantial. If you are expecting it to be dropped or rough handled (placed not-gently onto bricks), there is likely to be damage. Also, the edge experience the most force-per-area even during normal use, and could result in a small chip out.

Additionally, D2 might not be a "jump up"... it might result in lower toughness, making your concern more pronounced. See charts/tables on the link above.

I have experience at high hardness values in other steels, but only for straight razors and certain kitchen knives.
In this, certain users want a durable blade that requires less sharpening. Others prefer a softer blade that's easier to sharpen. A hide scraper seems (to me) like something people don't want to have to resharpen during usage, so maybe your goal is on point.

If it was me, I would split the difference... maybe aim for 62Rc to gain some hardness without sacrificing all the toughness. And experiment! I have no moose hide experience, but it would be worth the investment to try out 3 differently hardened scrapers and see how they perform.
 
Thank you for that response. Super helpful, I didn't pay attention to the toughness at 64rc being *that* low. I just re-read that article earlier today! I seem to be spending a lot of time on Knife Steel Nerds lately. I think you're right about 62 rc potentially being a safer compromise. I have some blades in the tempering oven right now going to try 62 and 64 and see how it goes, but it's nice to have that hard data as a starting point.
 
Stainless steels aren't in my wheelhouse at the moment, but a glance at AEB-L says it definitely warrants further investigation. In the meantime, I have a nice stack of A2 scrapers ready to heat treat so want to figure out how to maximize their potential for the application. Thanks for your response
Seedy Lot said:
I would recommend AEB-L. Stainless but fine grain and carbide, think stainless 52100. I made a hide scraper for myself out of AEB-L and it is awsome. Also AEB-L is one of the least expensive steels.
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What about inserts made from new HSS power saw blades? The body of the tool could be made so the inserts could bolt on with screws. And you could easily get about 20 inserts from one blade and they are already professionally heat treated and very wear resistant. You would need ceramic belts for grinding and carbide drill bits for drilling.
 
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