At this point in my knife making career I have developed my forging to the point that my blades are nearly 90% to shape when I get done at the forge. I have recently made a kitchen knife for a family friend and I got it really thin before the quench which ended up giving me a wavy edge. Luckily I had enough width that I could grind that portion away and still finish the order. Some time has passed since then and I have received another order for a much larger but still very kitchen style knife. Since the stakes are higher with this order I don't want to loose 30% of my width because of a bad quench. So should I just leave it thick and heat treat that way or is there a better way to keep it from warping while still having it very thin before the quench.
kitchen knives I heat treat before grinding, right from forging most of the time I dont even let them cool.
The edge ripple is generally happens heating from cold the thin edge heat first expand and ripples. If you heat slowly enough to 600-800 so that every thing expands at an even rate, that will not happen or as you said leave it thicker.
MP
Thanks for the quick reply Matthew. I was watching Nick Rossi forge that cheff knife on the ABS YouTube channel and thinking he's forged way thinner than I am. How do they get away with that.
Everything we do as Bladesmiths/Knifemakers a "give-n-take" situation.....we generally give up one thing, in order to achieve another. When it comes to heat treating in my shop, ANYTHING in the 1/8"" thick range or less gets the profile ground, then heat treated..... no edge bevel grinding or thinning down at the forge prior. That's the "give-n-take" in this situation.... in order to avoid the warping, you leave things thicker, but have to grind more.
As Matt mentioned, heating slowly so that everything expands more or less the same will minimize the warped edge(s). The trick is to find what works best for you. After many years of wrecking thin blades via warping during heat treat, and trying different things, I developed the general rule I stated above.
The one thing that experience has taught me is that there are some situations in Bladesmithing were you can easily forge too much towards "finished".<img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />
Ed Caffrey, ABS MS
"The Montana Bladesmith"
www.CaffreyKnives.net
personal I forge as close to shape as possible, like Nick (i have watched his demo in person) I forge my chefs as close as I can to shape 1/8 or under at the spine and 0.030 or so at the edge.it takes hammer control and a properly dressed hammer but it is not terribly difficult. I can normally get students to get almost that close in a two class, my two day kitchen knife class has been ridiculously popular so I have had a lot of practice teaching it.
I only profile them if I boned something and have a feature I am concerned will be a stress riser. (cold shut or hammer mark in the edge)
MP
Thanks guys for the help.
Here's an update on the knife I mentioned several days ago. I did do some stock removal on it prior to heat treat but kept it to a minimum. Had a little warpage towards the tip but fixed it easily. Thanks again for the help and let me know what you think.
