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8670 Journeyman Knife - Self Testing

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Bobby Best
Posts: 23
Eminent Member Apprentice Bladesmith
Topic starter
 

Good Afternoon!

I have built and self-tested my journeyman style knife, and I want to share what I've been able to do with 8670 and take whatever additional input I can get before I schedule my meeting with the local mastersmith. This isn't the first version of this knife, but it is the one that passed most easily for me and is what I'm going to replicate as closely as possible for the final version.

Steel: 8670 (alpha knife supply) 
Size and Style: Basic full tang camp knife, as big as the limits would allow (~10" blade, ~2" wide, and ~5" handle when forged, so slightly less after grinding)
Handle: None, which was a mistake for the woodcutting portion. Will add a micarta/g10 handle with some epoxy and 1/8 pins for the actual test one. 

Heat treatment after forging largely follows what Dr. Thomas has, with some slight modifications based on how my particular oven likes to cycle around the target temp:

1550f, soak for 10 mins, air cool
1450f, soak for 10 mins, air cool, 
1385f, soak for 30 mins, kiln cool for an hour then air cool 

Grind up to 120 grit, round everything off slightly. 
Used a clay hamon mixture (rutland dry mix, 3 parts dry to 1 part water, with ATP 641 as my antiscale). 8670 takes a terrible looking hamon, but it DOES take one, and makes it real easy to tell if I hardened where I wanted with a quick etch. Doing it this way was recommended by someone who already passed and it seems to have worked out, especially since it doesn't have to be pretty. 

Austenitize at 1505f, hold for 10 mins, quench in parks 50. 
Temper at 400f for an hour, air cool, then another hour at 400f, and a final air cool. My 60 hrc file just barely starts to grab it, so I'm estimating it at 59 hrc and that lines up with Dr. Thomas' testing. 

Placed the edge in water, blue-backed the spine and tang with a torch. Just to be safe. 

Full flat grind, or as close as I could freehand. Needed the freehand practice, since my mastersmith absolutely expects that to be in my skillset and made that very clear.

Measurements:
.130" at the thickest part of the spine, base of the blade. 
.100" about halfway up
.080" near the tip

The flat grind I brought down to ~0.030" for the edge before I used the slackbelt to sharpen. I've seen some tests taking 8670 thinner, around 0.020" behind the edge with a 15 degree per side grind, chopping through a lot without damage. But that instinctively felt a bit too thin for me and the .030 just felt right. Slackbelt sharpened up to 1000 grit, touched it up on a 5000 grit stone, stropped, and did a single pass with a white sewn buffing wheel with a bit of pink rouge on it. This gave a sharp, but not extremely sharp knife. All of my current kitchen knives I'd say were way sharper, but I'd rate this as a slightly dull chef's knife level of sharpness. 

Cut the rope like it wasn't there. Repeated several times to make sure it wasn't a fluke, and every time it passed right through it. 
Cut through the 2x4 twice without issue, other than it being incredibly uncomfortable and turned in the hand easily without a handle. 
Survived the bend test without any cracking.

So for the final version I'm bringing the fit and finish up to a proper level and adding a handle. Any other advice (for the blade or just in general preparation for the test day)?

 
Posted : 03/11/2024 10:42 pm
Michael Samdahl
Posts: 64
Trusted Member Apprentice Bladesmith
 

Bobby Best,

One of Kyle Royer's Videos on the JS knife make up he mentions using a 550 cord handle. I believe it is not against the rules and it is one that is quite comfortable from personal experience in consistent striking (Cutting 2x4) etc. I was told the same thing on the freehand grind requirement, I guess it is possible for the MS to possibly require proof that you can grind without the use of a jig or tool similar to the "Supplemental Test" Requirement for "forging a blade of any style". I have also read that having a minimum 220 finish will help keep the possibility of anyone thinking a scratch is a crack from happening. Triple check your measurements on the knife. I have been told by a couple folks that any requirement miss is a trip home, so some folks have taken a 1/4 inch back from the maximum in each category.

"While not a part of the formal test, the applicant is strongly encouraged to bring several finished knives for the Master Smith to inspect for quality of workmanship, fit, finish, design, etc. The feedback from the Master Smith is intended to help the applicant better evaluate if the quality of his/her work (design, detail, finish, etc.) is likely to meet the criteria of the ABS Judging Panel at the annual show." I would definitely plan on bringing the best you have produced, a notepad, and some thick skin. The more you get beat up sooner, the more you can gauge your expectations.

I am not a cert smith (praying to make it), but this is the best article I have read on the test. But I would say the more you read and understand for the test the better. No one goes home sad from being overprepared.

https://www.caffreyknives.net/abs_perf_test_art.html

https://www.caffreyknives.net/js_test_blade_art.html

It looks like you are going through the data methodically, good job!

Respectfully
Michael

 
Posted : 04/11/2024 5:57 pm
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