Blacked-Out Chopper for TMS 2015

D

Don Nguyen

Joined
Oct 4, 2011
Messages
1,043
Hey everyone,

This year I spent a good amount of time working on an experimental knife for the bladesmithing competition at TMS 2015. The requirements were that it needed to be forged and also needed a video, characterization report, and poster. I attempted to do a chopper of 52100 with a martensite edge and a martensite/bainite duplex spine.

Unfortunately I didn't place in the competition, but I learned a lot and will improve a ton from it. It also made a big impression, which is what I wanted at the very least. I want to thank Aldo for 52100, Chuck Bybee for the C-Tek, Travis Wuertz for forge access and materials, and Sonia at Tempil for a series of Tempilstiks.

Finished Knife:

9jQqIxA.jpg


Video (Disclaimer: I don't claim to know anything about anything. I'm probably doing many things incorrectly):

[video=youtube;1kq5YUxb3OQ]https://www.youtube.com/watch?v=1kq5YUxb3OQ[/video]

I'll have more details up soon, and another photo.

Thanks!
 
Great video and knife!! You had a big surface to polish, eh eh eh ;)
Don, did you do something to "reinforce" the black etch on the blade, or just etched in ferric? Somewhere i read they go from the ferric to boiling in caustic solution to make the black oxide more permanent; did you do something on this line?
 
Thanks everyone!

stezann said:
Great video and knife!! You had a big surface to polish, eh eh eh ;)
Don, did you do something to "reinforce" the black etch on the blade, or just etched in ferric? Somewhere i read they go from the ferric to boiling in caustic solution to make the black oxide more permanent; did you do something on this line?
Click to expand...

I just did a straight etch on it. I'll have to read up on the extra treatments!
 
Wow, that is quite a stylish chopper Don! and I'd expect nothing less ;) Great vid too, always fun watching things come to life at cracked out squirrel speed lol Great job on the forging of the blade btw, I wasn't aware you did much forging, but you really did a great job getting that all shaped up :thumbup: So what are you using the Tempilstiks for, just double checking your oven pyro, or..? I was thinking about getting some for when I heat treat in the muffle in my forge to use along with my pyro... but could you provide any info on those and how ya like 'em? I seriously like that blackout finish and sculpted handle! Thanks for sharing :)

~Paul
My YT Channel Lsubslimed
 
I remember John Doyle said he sets the oxides by boiling in baking soda...you can contact him for details. I don't know if the method makes the black more wear resistant or if it is used to convert any possible active rust starting nucleus to magnetite.
 
Looks real nice. The handle looks like it has a right angle near the bolster, does that create kind of a hot spot when cutting?
 
Thanks guys!

coldsteelburns said:
Wow, that is quite a stylish chopper Don! and I'd expect nothing less ;) Great vid too, always fun watching things come to life at cracked out squirrel speed lol Great job on the forging of the blade btw, I wasn't aware you did much forging, but you really did a great job getting that all shaped up :thumbup: So what are you using the Tempilstiks for, just double checking your oven pyro, or..? I was thinking about getting some for when I heat treat in the muffle in my forge to use along with my pyro... but could you provide any info on those and how ya like 'em? I seriously like that blackout finish and sculpted handle! Thanks for sharing :)

~Paul
My YT Channel Lsubslimed
Click to expand...

Paul, the Tempilstiks were for gauging temperature when I did the interrupted quenches. I needed to know when to take the blade out of the initial quench and onto the next since I was trying a relatively complex and experimental procedure (to me at least). I found that once the quench stops gurgling it's at 650° F; if I took it out any earlier it would flare (learned the hard way).

gregorio said:
Looks real nice. The handle looks like it has a right angle near the bolster, does that create kind of a hot spot when cutting?
Click to expand...

Overall the handle isn't bad, there aren't hot spots but there are definitely adjustments I'd make for the next. Making these handles are not easy, and I have much respect for the guys who do the really nice contoured handles.
 
Don Nguyen said:
Thanks guys!

Paul, the Tempilstiks were for gauging temperature when I did the interrupted quenches. I needed to know when to take the blade out of the initial quench and onto the next since I was trying a relatively complex and experimental procedure (to me at least). I found that once the quench stops gurgling it's at 650° F; if I took it out any earlier it would flare (learned the hard way).
Click to expand...

Oh okay I gotcha.. So did you do this by experimenting on some scrap by taking it to critical, quenching, interrupting the quench, then marking it with multiple Tempilstiks and seeing which one(s) melted and which didn't etc. Sorry, just having a hard time trying figuring out how ya went about it. Seems like if it was done the way I just described, then by the time you marked the steel with multiple Tempilstiks after pulling it out of the quench to gauge the temperature, that the temp would have significantly dropped, or at least enough to make a difference when it comes metallugical experiments. Please ignore my ignorance regarding all this :o lol Thanks man :)

~Paul
My YT Channel Lsubslimed
 
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Don, Thanks for sharing! Your video was super cool and the chopper.... wow! The organic shape is beautiful! Watching your finishing techniques makes me enjoy my gyuto even more!

-Will
 
coldsteelburns said:
Oh okay I gotcha.. So did you do this by experimenting on some scrap by taking it to critical, quenching, interrupting the quench, then marking it with multiple Tempilstiks and seeing which one(s) melted and which didn't etc. Sorry, just having a hard time trying figuring out how ya went about it. Seems like if it was done the way I just described, then by the time you marked the steel with multipul Tempilstiks after pulling it out of the quench to gauge the temperature, that the temp would have significantly dropped, or at least enough to make a difference when it comes metallugical experiments. Please ignore my ignorance regarding all this :o lol Thanks man :)

~Paul
My YT Channel Lsubslimed
Click to expand...

That was the basic idea. The temperature drops after taking it out of the quench were actually pretty slow. I could hold it at above 400° F for probably a minute just in still air. The important part of it for me was to ensure that the spine never dropped below the martensite start temperature. By the time I'm done with the second quench the body of the blade is still at above 500° F.

This could be a very ghetto method to get what I wanted, but at the same time it was just a Frankenstein'ed experiment I've always wanted to try out :)
 
Thanks fz1boxer!

willic said:
Don, Thanks for sharing! Your video was super cool and the chopper.... wow! The organic shape is beautiful! Watching your finishing techniques makes me enjoy my gyuto even more!

-Will
Click to expand...

Will I didn't even realize you commented right before I did. I'm glad the gyuto is working for you so far :)
 
interesting handle design.
how did you come up with it?
how did it work for you in competition and what would you change if anything?
how would you price this knife?
 
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