Grind warp?

Pelagicfun

Pelagicfun

Joined
Oct 16, 2017
Messages
245
Starting my first thin kitchen knife out of thin 15n20. I ground in maybe 50% of my bevel prior to heat treat 1465 oven, 50 oil, plates and temper. Im sure it was straight. After i dug into one side i noticed that the blade was curved into the grind. Is this a thing? I guess i can understand how it would happen but did i overlook something else? If so when grinding thin stock should i keep sides even and not finish one side at a time? Was it lack of normalizing cycles?
Thanks
CC
 
They can indeed warp with the grind. Just like you thought do it in stages on each side to minimize. I do AEB-L 90% of the time and it will definitely warp during the grind. You probably shouldn't grind any type of knife or steel all the way on one side at one time.
 
I've made several full size chef knives out of 1/16" 15N20, and yes the grind warp is a thing, especially if you grind unevenly.

What has worked for me is to work down each side at the same rate, doing about a 1/2" facet (one pass) then going to the other side. I also found a periodic stress relief of 1 hr at 25° F below tempering temp to help if you start getting warp.
 
Just The pressure on the blade combined with it heating up a bit while grinding post HT on a thin bade can bend/warp the blade. It is easy to straighten out.
 
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