14c28n breakage

[HikoIto]

I got 14c28n blades back from HT and noticed one of the blades (0.100") had a slight bend near the handle. I placed the knife on the edge of the table and pressed down slowly to straighten it. The blade snapped in half. Is 14c28n brittle? Should I worry about the HT on the rest of the batch? How do you guys deal with the bent blades after the HT? Thanks.

 

[quint]

Isnt that a razor blade steel? What hardness did you get it HT too. For one thing you cant just bend it to get them straight again. Not sure with stainless but carbon steel you need to retemper and bend at temper heat then usually did in water to cool rapidly. Ive done this several times but I dont work with stainless.

I imagine any blade that thin at a higher hardness will snap relatively easy (I guess depending on your definition of easy).

 

[Stacy E. Apelt - Bladesmith]

I have broken many blades over the years....usually when I say, "I'll just reverse bend it a bit to get that small warp out....." immediately followed by, "PING".

Straightening a small warp/bend is not difficult, but is best done at 400°F and done with carefully applied force. Even then, some blades will snap.

If the hardness is above Rc59, breakage becomes more of a problem, and with thinner blades, the problem increases.

 

[Atlas Knife Company]

I've had it work with all the stainless I've had to do it with. Temper once, clamp it to a piece of angle and temper again while clamped. If the warpage is severe, I'll do multiple steps to straighten it. I usually use a penny behind it to reverse bend during the process.

 

[Alpha Knife Supply]

Who heat treated your blades?

What hardness?

Chuck

 

[HikoIto]

I send my blades to PA for HT. 60RC. I can't say the warpage was caused by the HT, I probably missed it beforehand. Thanks.

 

[HikoIto]

I just checked the rest of the batch for straightness. 50 percent of the batch were warped :/ I seriously need a good surface grinder...

 

[Ken H>]

Depending on amount of warp - use a magnet to hold blade to platen to simulate a surface grinder. While this platen method won't assure even thickness from one end of blade to other, it will help take a "small" amount of warp.

Ken H>