Monday, May 5, 2014

KN5 - HEAT TREAT & CLEAN UP


For the Chef's Knife I finished the blade a bit better, marked and drilled the scale pin holes, cleaned it up and made an envelop of stainless steel.

Clean up the blade a bit more with 220 grit and WD-40.


After drilling the three pin holes for the scales (3/16" pins) I wiped it down with acetone to remove any layout dye and wrapped in foil. It's ready for the oven.

The HT recipe I am using is 1060°C (1940°F), 15 minute soak, plate/air quench. Tempering at 175°C (350°F) for two 2-hour cycles. Target is Rockwell 58 to 59.
While the oven is heating up. I am finishing the bolster ends with some 220 grit.
Also, while the oven is warming up, I'll get to the scales. I'll be using double-dyed blue and red bird's eye maple from WoodStabilzer.com.






DRAMA!

Pulling the envelope out of the oven, I lost grip on my pliers and sent the envelope to the ground tip first! I have about a 3/8" wow on the end. What to do with it?

I can do nothing now as it would snap in it's current brittle state. Into the tempering oven for a few hours. One option is to try to straighten out the tip: the other to carefully grind the tip back and reshape the blade.

I tried to straighten the tip out in the vise. I got pretty far...
Until this happened. I was thinking that it would snap.
Using a slow speed (about 1200 FPS) on the belt grinder and a 60 grit belt I reshaped the tip. It's a little shorter, but salvageable. I wanted to avoid any heat when grinding so as to not kill the heat treatment on the blade.





 I worked this up to 320 grit. I'll leave it at that. Kitchen knives don't go well with mirror finishes. :-)







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