What should I do?

[710-1401guy]

A few weeks ago I got a Benchmade 710-1401 from Knifeworks. I love the knife but I think the blade was not heat treated right. When I sharpened the blade it could push cut phone book paper but I broke down a box and it lost its edge really fast. I know this might be normal for lower end steels but this is a m390 blade as most of you know and it is supposed to hold its edge longer than that. So should I buy a new blade from Benchmade or see if it is covered under the warranty. Thanks in advance!

 

[RevDevil]

Cardboard contains a lot of things, it is not only recycled paper and glue. There can be pieces of wood, metal, silicates, dirt, and many other things; it also depends on where the cardboard is made. It is not uncommon for a knife to need a touch up after cutting cardboard. What angle did you sharpen the knife to? Did you build up a burr? If so, did you remove it? I think buying a new blade might be a little premature at this point. The same may go for warranty service, there might not be anything wrong (in Benchmade's eyes anyway) to repair.
ETA- I'd be interested to know what the Rc hardness of the blade is.

 

[powernoodle]

If you sharpened it to acutely (too thin), it will be sharp initially but will dull quickly. You might try sharpening it on a system like the Edge Pro Apex (spendy) in order to get the edge angle just right, or send it to one of Bladeforum's gurus to sharpen it, and see if it holds an edge after that. If so, the blade steel is not the prob. Benchmade also has excellent customer service, and you might send it to them for sharpening and/or for their counsel. But I think its more likely to be a sharpening issue than a heat treat issue. Good luck.

 

[710-1401guy]

Thanks for the quick responses! The angle I re-profiled it to is 40 degrees because I thought the edge retention would be higher than that of a lower angle. I think I will try stropping it then testing the edge retention on other cutting medias. If I get similar results I will know if the heat treat is bad or if was just that cardboard. Again thanks for the quick responses, the information was very helpful.