First knife... have I messed up?

D

David Parker

Joined
Apr 28, 2018
Messages
5
Hey I’ve been reading the forums here for a while and they’ve been incredibly useful with making my first knife... really I just wanted to make a really nice chef knife that I’d use all the time and I figured why not take the time to make my life harder and attempt a hamon ¯\_(ツ)_/¯

So far I’ve found answers to all of my questions here but I just tried etching the Hamon with lemon juice and I’m stumped. It’s hard to see in the photos but the Hamon worked great towards the tip of the blade but then seems to taper off until the last inch and a half is unaffected.

6_FC16_E83_58_F1_48_DC_B1_E8_DB2_E8_D2_FCF20.jpg


My questions are; does that mean that portion of the knife edge isn’t fully hard/heat treated?

The blade is now down to 0.01” can I/do I need to heat treat again?

I took a little video of me quenching the blade which is on my instagram here incase I didn’t plunge it quick enough or something? https://instagram.com/p/BiGP8p-hQr_/

(Steel is 1075, I heated the blade in my mini forge until non magnetic, quenched in canola oil and tempered at 375f for an hour, twice. When sanding after that I made sure to, keep the blade cool the whole time)
 
It’s tough to tell from the video but it appears the blade was cooler back towards the heel, and may not have been up to proper temperature. The way the Hamon runs off the blade is a fairly solid sign that the back 1/3 or so of the edge didn’t fully harden.
 
Grayzer86 said:
It’s tough to tell from the video but it appears the blade was cooler back towards the heel, and may not have been up to proper temperature. The way the Hamon runs off the blade is a fairly solid sign that the back 1/3 or so of the edge didn’t fully harden.
Click to expand...

Thanks yeah, after posting this I went back and looked at the video in slow motion and it does look like it wasn't hot enough! It was all a blur but I'm wondering if I double checked it with the magnet before I quenched it instead of going back into the forge after checking the magnestism. Can I re-do the heat treat (and focus more on the handle end and not panic so much)? And if so should I maybe take a a little off the edge of the blade until it is back to 0.025 (like it was when I originally heat treated it) so it isn't too thin? Or should I be fine to heat treat with an edge about 0.01"
 
Remember you need to go hotter then the curie point. According to a few sources the austenite range for 1075 is 1475°-1550° and the curie point will most likely be under 1400°. It’s probably close to around 1375° Or so.
 
David Parker said:
Thanks yeah, after posting this I went back and looked at the video in slow motion and it does look like it wasn't hot enough! It was all a blur but I'm wondering if I double checked it with the magnet before I quenched it instead of going back into the forge after checking the magnestism. Can I re-do the heat treat (and focus more on the handle end and not panic so much)? And if so should I maybe take a a little off the edge of the blade until it is back to 0.025 (like it was when I originally heat treated it) so it isn't too thin? Or should I be fine to heat treat with an edge about 0.01"
Click to expand...

Yes, thicken the edge up a bit and redo the heat treat if you're not sure you did it right. Try to form a uniform color along the blade before quenching, avoid hotspots. And check the edge with a file after the quench to make sure it hardened.
 
Congrats David! (Hey....nice name there!) Very nice. You should be very proud my friend. And know that you belong here.
 
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