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JS Performance Test Knife
I've decided it's time to get serious about a JS performance test knife and thought I'd share part of my experience. I've "tested" many blades in the shop , but none were to precise ABS requirements. None of them were built to parameters and/or with serious intent. Most were blades I'd made a mistake on and decided to destroy for one reason or another.
As I begin, I'll be building these blades with one intent in mind, and that is to pass the ABS performance test. This will be my main focus in the shop until I've worked through the challenges and have destroyed enough "passing blades" at home that I've become confident enough to test for real (timeframe tentatively set with MS).
I'm going to experiment with several different things for comparison (geometry ideas, edge vs through quench, soft backing, hardness, etc.). Even if my first "recipe" happened to work out, which is unlikely, I have a lot I want to learn during this process.
My update posts won't be long and arduous to read. Quick and simple. Worked or didn't. I'm keeping a personal journal to document all of the lessons learned.
My blade design will start out as a "competition chopper" style with a blunt tip/end.
- Forged from 1 1/2" x 1/4" 80CrV2
- Blade length - 9 3/4"
- Blade width - 1 3/4"
- Overall length - 14 1/2"
- Full distal taper with a convex grind
- Paracord Handle
"Blade #1" has been forged, rough ground, heat treated, and is currently waiting on me this evening to finish grind and sharpen. I'll be testing it this week!
Wish me luck.
Time for bed. Knife is finish ground, handle wrapped, sharpened, and ready to test after work tomorrow.
I ran the finish up to 220 on the platen and then gave it a few passes on a surface conditioning belt.
It was pretty sharp after convexing, but finished final edge on stone. It shaves, tested fine on a brass rod, and doesn't hang up anywhere when cutting slowly through paper.
Let the games begin.... 🙂
Hey Matt! Many Thanks for taking us through your experiences! I think that sometimes, in today's world, individuals get so caught up in trying to learn HOW..... that they never actually DO...and there's simply no substitute for the "hands on" portion of learning!
Blade #1 outperformed my expectations! This "recipe" should serve as a solid baseline for more testing.
Rope cutting technique makes a difference. First swing cut 2/3 through due to me "stopping" the swing instead of swinging "through" the rope. Cut the rest of the way through to get rid of excess. Next swing, cut through it easily.
Chopped through 2x4 without any edge damage. Impressed with how tough it is being so thin. My paracord handle wrap sucked and I'll be re-evaluating wrap style and/or handle material in general. It loosened up during the chop. Also will be changing the shape of my handle slightly.
Shaved hair successfully with the "used" edge. Could be sharper I think. Test was performed with a Norton India stone finish as I forgot to touch up with a hone or strop.
Decided to practice rope cut technique some more before bending. Cut the rope 5 more times and edge seemed perfect still.
Was able to bend the blade to a 90, or just a hair past using my Dad as a spotter 5 times in total before it snapped. Grain structure looked smooth and creamy.
I'll forge two more blades to the same dimensions tomorrow and hopefully have them ready to test by early next week. I'll be using same exact recipe to see if I can duplicate similar results before trying some new things. I want to know where the baseline is so that I can return after I push something too far.
That whole process was more fun than a grown man should be having to be honest. We shall see if it was beginners luck or if I can produce similar results. I added a few links to pdf's containing pics below for your viewing pleasure. I'm open to any and all feedback. Wish me luck on upcoming blade #2 and #3.
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Thought I'd add the info I'm logging in a spreadsheet for all blades in preparation for my JS performance test in case anyone is curious.
- Blade #
- Post testing and overall build thoughts
- Performance Results
- Dates forged and tested
- Steel used and supplier
- Knife style
- Finished blade length, width, and OAL
- Handle material
- Pre-HT edge thickness
- Distal taper measurements from tip to handle
- Steps and temps for HT recipe
- Quench oil and temp
- Quench type (edge or full) and details
- Edge thickness pre convex, convex height
- Sharpening info.
Just a couple of my thoughts, based on many times supervising JS and MS tests. Handle: Put on a real handle. I recommend something like a Micarta or G10. Either of these materials are very durable, and will lend strength to the handle (I've seen a number of people fail because their handle bent or broke at a hole in the tang/handle, AND they were using a wood or cord wrapped handle). Another issue with cord wrapped handles is that there is always the chance, that the supervising MS COULD declare a cord wrapped handle as "unsafe"..... and COULD fail you base on that alone. (Wink, Wink).
Also, remember that any official test knife MUST have a lanyard, that must be used during the tasks required of the performance test. This CAN have a bearing on testing because if you've not conducted your "homework" using a test knife with a lanyard, it can mess up your technique. I actually find that FOR ME using the lanyard helps with the chopping portion of testing.... I allow the knife to "pivot" on the lanyard, and my hand only keeps the blade level/straight.
There is certainly a "technique" to each of the required tasks set forth for a performance test knife. You've already learned about "cutting through" that hanging rope cut. I would also all to use some tape spaced about every 6"... because the rules stipulate.... "The hanging end of the rope is to be marked
with tape or a marker to clearly indicate the area that is to be cut. The cut must be
approximately six (6) inches from the end of the free hanging rope. A minimum of one (1) cut
must be made. The applicant is to aim at the mark with a two (2) inch margin of high or low
being acceptable."
When it comes to the chopping portion of the test, I would encourage you to strive to cut through the 2x4s in as few number of strokes as possible. Why? The fewer strikes on the wood, the less likely you are to damage an edge that is required to shave hair immediately following the chopping. And keep in mind that the shaving test is: The applicant must then shave hair using the section of the blade that was most
frequently used in the cutting and chopping portions of the test. IF a blade has the correct geometry, and the correct working hardness, it should easily chop through a 2x4 in 8 or less strikes. I've seen a couple of MS test blades do it in 5 strikes. Of course there isn't any "extra credit" for a blade doing that, but suffice to say that fewer chops is almost always better then more. Case in point, I tend to count the number of strikes when I am supervising a test, and can tell you that nobody has ever passed if they took more than 15 strikes to cut through a single 2x4. I had one individual that "tapped" his way through a single 2x4 with 60+ strikes. Needless to say, his blade's edge was dull as a post afterward.
Since I'm this far, the "trick", if there is one to the bending portion of the test, is to bend the blade SLOWLY AND SMOOTHLY! (and if offered a leverage device such as a piece of pipe or steel tubing.... USE IT!) I've had a few failures due to the individual getting to about 75-80 degrees (90 is required), and during that last little bit, it was like they stopped for an instant, then JAMMED the blade over, causing either a large chunk to pop out of the blade, or the entire thing let go and broke. A few of those times,it was the individual's fault...as I had offered them a pipe to put over the handle, but they refused the offer, and didn't have enough body weight to bend the blade over. So the sorta hopped, and tried to put their weight plus more, and the blade popped.
Thank you for the feedback. I'll put the advice into practice!
Lesson learned on the handle material for sure. I've always used "hard" handle material and haven't ever wrapped a knife in paracord (if you couldn't tell lol). Knew I had to change it as soon as I hit the 2x4. My reasoning behind trying the paracord was to avoid putting holes in the tang. Canvas Micarta and 1/8" copper or brass pins going on blade #2.
Lanyard - Will definitely incorporate into blade #2
Ugh.....!!!! I bet I've read the testing rules at least 50 times and thought I had them down pat, but I didn't. I taped the very bottom of rope, measured up 6" and wrapped in electrical tape to mark it. Aimed in between tape marks and sliced it thinking I was golden. Thanks for pointing this out as I want to simulate the official performance test. I'll mark 6" from end and aim at that mark going forward.
2x4's - I agree 100% with your recommendation and approach. This was my mindset going into it as well. I didn't count, but will going forward as it'll make it more fun. I like having a target.
Bend - Watching the video, my first bend took me about a minute and a half and went smooth. Knowing that it had "passed" my personal test, the next four bends were definitely rushed through way too fast (my adrenaline/sense of relief was likely running too high). You described the "snap" perfectly. I took another grip on the pipe and gave it too much of a final push. I used a cheater pipe and won't turn down an offer during my official test.
Looking forward to making some adjustments and experimenting with knife #2!
Knife #2:
Forging complete late last night and it's sitting on the bench waiting for some attention as we speak.
Details:
- Forged from 1 1/2" x 1/4" 80CrV2
- Blade length - 9 3/4"
- Blade width - 1 3/4"
- Overall length - 14 1/2"
- Follow same HT process as #1
- Full distal taper with a convex grind
- Drop point tip vs. blunt tip/end tested on #1
- Micarta handle material with two 1/8" pins and a lanyard hole
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Drilled pin and lanyard holes in handle and finished up final tempering before bed last night. I plan to finish grind, sharpen, and handle it up tonight after work. Shape handle tomorrow and see how this one performs.
Noticed a slight warp in the blade after the 3rd thermal cycle but it was easy to straighten and was likely my fault. Grinds are all flat and even with a consistent edge thickness. I used to see a lot of warping before grinding/forging improved and I started using good quench oil, but I haven't had many for awhile so I was a bit confused.
I typically clamp the end of the handle in a vise with point in the air as it cools between cycles. Decided to put it spine down on a fire brick after coming out of the oven the 3rd time while it cooled (wanted to film a quick video of it for my daughter). Not sure if that was the culprit or not, but I won't do that one again lol.
Likely useless nonsense that wasn't worth sharing, but it irritated me 🙂
I'll post an update after performance testing practice blade #2!
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Knife #2 outperformed #1 in every category of the performance test. After one successful rope cut and chopping 2x4 twice, shaved and confirmed no edge deformations. Then proceeded with more rope, 2x4, and shave tests prior to bending. Removed sharp edge prior to bend and used cheater pipe on handle.
Notable differences between the two knives:
- Micarta, pins, and lanyard tubing vs paracord handle material
- Blade profile
- Edge thickness prior to quench and post convexing
- Sharpening steps
- Lanyard
- Hand sanded blade and applied makers mark.
- Note - I didn't finish to show table ready whatsoever for obvious reasons
A few of the lessons learned:
- Detailed journal spreadsheet is invaluable for me to reference prior testing
- Micarta handle material and a lanyard....yes, do that.
- Practice on technique chopping 2x4. Taking me an average of 15 strikes. I wasted some strokes due to inaccuracy when chopping extremely hard.
- The ease of travel and the "wisp" or "snip" sound you hear when the rope falls straight to the floor is satisfying. Although Blade #1 passed this test, there was no comparison between the two.
- Bending a blade to 90 degrees is nerve wracking regardless of how many times it performs for you
- It's extremely satisfying to build blades with the sole purpose of experimentation. It's a stress free situation to figure out what works and what doesn't.
- Minor adjustments can have a very big impact on performance.
I'll forge practice Blade #3 tomorrow after work!
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