Hand Tools Archive

Re: Stress vs strain
Response To:
Stress vs strain ()

"2. The test as described doesn't distinguish between elastic and plastic strain, so a softer material that deforms plastically would appear to last longer even though it's useless as a knife once it starts to deform. Softer materials will therefore appear to do better."

Not a huge fan of the ABS tests, but they bend them 90 degrees, and then back, and then they do a cut test, and examine the edge for chips. It has to do all that. Basically they want using characteristics that allow easy sharpening, long edge holding and the ability to take abuse as defined by bending without loosing the edge, vs not bending at all.

The a thing called a copper rod test I think. Where you deflect the edge by pressing on it with a copper rod. I think just copper so the edge isn't dulled, or the rod slip. But that is the key point. It just deflect, doesn't chip but does the number of rope saw throughs you want.

I think the reason for the bendability is just that you can get that in a forged knife, stock reduction probably could also, but they don't shoot for it. It seems to smiths to be the natural excellence in the forged knife. But that is cultural.

© 1998 - 2017 by Ellis Walentine. All rights reserved.
No parts of this web site may be reproduced in any form or by
any means without the written permission of the publisher.