Jump to content
I Forge Iron

A Destruction Test Knife WIP


Recommended Posts

This will be the third of my knives to be subjected to the rigors of the ABS JS testing criteria. I did the first test on a 5"-bladed hunter 3 years ago and it failed the bend test.... achieving only a 25 degree bend until cracks appeared along the sharpened edge extending approx 1/3 into the blade. The second was also a hunter style blade, 5", that managed an almost 40 degree bend before similar cracks appeared near tip. I know I can do better.

This time I'm building a 8 1/4"-bladed, harpoon-tip chopper that will be built to my usual standards of fit and finish. The blade is Aldo's 1084FG, forged to shape with a distal taper and forged bevels. I plan on an fitting the blade with a mild steel s-guard, copper spacers, and a Red Oak handle.

So away we go:

Yesterday I forged the blade:

Initial heat:

Almost there:

The blade is shaped, but not the tang....... yet. I'm getting there.

I seem to have lost several shots of the tang forging and final shaping process. However, the tang was forged to rough shape then the whole blade final-shaped and the bevels ground. I pick up the action with the following steps. Its also pretty clear that I consumed way to much tea last night resulting in these jittery, blurry shots.

Post heat treat/temper. The blade was heated to 1500 degrees F and soaked for 5 minutes, then quenched in 130 degree canola oil. Tempering was done at 400 degrees for 2 hrs x 2.

Sanded with 220 to remove all the crap:

Sanded to 400 with copper maker's mark plate roughly shaped:

Here's where I stand this morning. Today I'll get the blade sanded to 2000 grit and hopefully get the guard started:

Link to comment
Share on other sites

  • Replies 64
  • Created
  • Last Reply

Top Posters In This Topic

I thought I'd post some shots of my shop and equipment for a bit of context.

These are my hand sanding implements:

Grinding and drilling:

My grinder set-up:

Clean work station for design and leather work:

Work bench:

Hand sanding set-up:

More this evening hopefully.

Link to comment
Share on other sites

That is really nice work and i am a longtime supporter of ABS standards for makers to see where they are at with forged blades after heat treat. And I am not an ABS member.Most of my knives aer stock removal stainless steel. However I used similiar testing procedures until I got the carbon steels and layered steels right with heat treat. i still make some knives with those stell and refer to my early testing each and every time. During those days I used to do destructive testing with blades prior to attaching fittings and handles. Seemed to work for me as if I had a probelm it was only with a blade. I think your post will open the door for some of the new folks to join you in your work and wot a commitment it takes to make sure heat treat is correct.

Link to comment
Share on other sites

The blade is now hand sanded to 1500 grit.
However, I ran into some "issues".

I've also drawn back the spine to spring temper(blue). I don't do this very often and I hate the process - likely because there has to be a better way. I take the blade to 800 or 1000 grit, then submerge the edge in water, heat to blue with the propane torch, clean up surface rust, then finish the sanding.

I began the heating at the choil and started moving forward. Then I ran out of propane!! After taking the time to refit a new bottle and finish the job, I was left with a substantial line in the blade at the waterline.

So, back to 400 grit and begin the process all over again. I finished up at 1500 grit last night at 1:45am.

If there's a better way, please advise.

This is one blade to 1000 grit....the first time!!

Set up for drawing the spine:

This is when I ran out of propane:

I'm working on the guard now. More later.

Link to comment
Share on other sites

I don't understand why you go to 1000 grit before the last temper cycle. The colors should be the same at a 220 or 400 grit finish, and you have less work to redo, unless you are leaving the colors.

Is this deep draw on the spine a normal technique that you use?

The propane problem is a good reason to have an extra bottle for the plumber's torch around. There are also adapter hoses to take to a bulk bottle.


Link to comment
Share on other sites

Phil, Matt - I've only drawn out the spine on two previous knives and I had not encountered that issue. The surface rust from the process is one thing and easy to clean up, but leaving the warm blade in the warm water for that change-over time "cut" in a rather deep line.

Every knife I make I learn something new and this has been no exception. I can assure you that I leaned my lesson and that subsequent blades will be done, as you suggest, just after tempering at 220 grit or so.

Live and learn.

Thanks for the advice.


Link to comment
Share on other sites

The blade is sanded to 1500 grit and the mild steel guard is shaped and dry fitted. I made this guard several weeks ago as a practice piece and just needed to adjust the profile a bit and file the tang slot to size. It looks a bit sloppy, but the fit is tight.

This is it for the night. Tomorrow I'll form a copper or brass(haven't decided yet) spacer as well as pre-shape and dry fit the Oak handle.



Link to comment
Share on other sites

Justin - I've made three knives with these peened tags, all much shorter of the hunter style. I just like the look, and plan on doing more. However, if I'm going to continue to do this, I need to know that the knife's integrity is not compromised..... especially on larger blades like this.

I know, I know..... if I want to make a knife that will pass the test, I should leave these out of the design. But, what I'm doing is trying to test what I like to make. If this feature fails, then I've learned a lesson, and will drop the concept without a second thought.

Link to comment
Share on other sites

I like the concept of the name plaque. If the holes are relieved properly and smooth then the stress concentration would be reduced (not eliminated). I doubt it will fail in that area because the metal is thickest there, but testing will tell.

Touch marks also create a stress concentration.

The name plaque can be relocated to the scales or guard on future knives if it is a problem.


Link to comment
Share on other sites

I hadn't really paid much attention to the testing angle on this blade until just now. I'll be shocked if it fails at the ricasso since, as Phil suggested, that's probably the strongest part of the blade -- and the stress is going to be concentrated further down the blade, where it's thinner.

Speaking of that, how thick is it? Remember that longer and thinner is more flexible than shorter and thicker.

On the question of wanting to test what you like to make, I would add a couple things. First, I think that's fantastic! But, second, you seem to assume that if "what [you] like to make" can't pass the ABS test, that means you're doing something wrong. And that isn't necessarily so. My understanding is that even the ABS does not claim -- anymore, at least -- that a soft-backed, hard-edged blade that can cut a 1" free hanging rope in one swipe, chop twice through a 2x4 and still shave hair, and bend 90 degrees without cracking too badly, is the ideal blade for all purposes. The test is supposed to assess your ability to design and heat treat a blade to perform to a particular standard, not to establish that standard as the universal measure of blade quality.

My point is that in the real world nobody is ever going to use one of your knives by locking it in a vise, sticking a cheater bar on the handle, and bending it 90 degrees. So if you do that to one of your blades and it fails, that doesn't necessarily mean it wasn't an ideal blade for the purpose(s) for which it was intended to be used. Depending on the blade, that might be a little like testing 200 mph sports cars by taking them offroading and, when they fail, concluding that they're bad sports cars. Y'know?

Link to comment
Share on other sites

Matt - The blade is 3/16th at the ricasso with a distal taper to near zero at the tip.

I just finished the copper spacer for this knife. Here's my process:

This backyard shed is where I keep my forge:

My Chili Habenero forge:

Anvil and canola oil quench tank:

I'm using a piece of an old boat propeller shaft for this spacer:

I'll use the small piece on the right:

Showing promise:

Forging is completed:

I just need a small portion of this plate:

I'll flatten on the belt sander:

Refining the surfaces and getting a consistent thickness:

All these little vertical scratches need to vanish:

Rough shaping is done:

Marked and drilled for the tang slot:

Filing one hole big enough to fit my saw:

Sawing out the remaining material:

The spacer has been filed and cleaned up a bit. It is now completed and ready for assembly:

That's all for now folks.

More to come...........

Link to comment
Share on other sites

Just wondering...., if you want a hardened edge and a soft back. Why not just edge quench from the beginning and eliminate the second temper draw in the water?
I'm not criticizing, just interested in your approach.


Link to comment
Share on other sites

Doc - The simple answer is: I just don't have a proper edge quench tank set-up.... at least for this large of a blade. I have a old roasting pan that I've used for small blades, but its hardly big enough for this piece. I could likely fit it in the pan, but I'd have no room for any agitation to break up the vapor jacket..... it'd just sit there.

I'm looking for an old, long ammo can just for this purpose.

I don't do it that often, but when have it hasn't been an issue for me. This time I just ran out of propane in the middle of the process and left the blade in the water wayyyyyyyyyyyy to long while getting a new bottle ready.

Link to comment
Share on other sites

Go to the farm store, or the big box store, and get an oblong wash basin, galvanized. It will be in cleaning supplies or animal care. The small ones are about 12 inches long, and the big ones are quite big.

Alternately, if you can suffer with a sports logo, I see similar basins at the grocery painted nice and fancy.


Link to comment
Share on other sites

Here's today's work:

To this point everything has been rough shaped and fitted. And it shows. So, the first thing is to clean up the blade/guard/spacer fit.

The shoulders need to be refined and radiused, and the adjoining guard slot needs to be fine tuned to accept the radiused shoulders.
There can be no light showing from this angle as well as from head on, and the fit will be tight and solid.

The next step is to refine the guard/spacer fit. This will entail removing a bit of stock from the contoured handle-side face.... essentially extending the length of the flat contact surface.

AFTER the guard/spacer fit is perfect, I can move on to the handle. I have a template from a previous project, that will work just fine for this knife:

Mind you, I will need to do this layout again after the fitting session described again, but......
Handle profile is transferred to the block and the tang is positioned appropriately. I then extend those lines to the end surface and layout the dimensions and position for the tang slot. ** keen eyes will detect that I'm using a block of fairly plain Cherry, rather than the Maple I earlier mentioned**

The blade, at the ricasso, is 3/16", so I'll use a 5/32" bit to drill the slot holes and then carefully refine the fit with broaches and files.

Being that the drill bit is only "so" long, this determines the depth of the hole I can drill and somewhat correspondingly, the length of the tang.

So, block and tang are marked with reference lines and work can begin. Again, I need to do this part of the layout again after guard/spacer fitting to get a more accurate layout.

So, there's today's work. I'll take photos of the process along the way.

Thanks for putting up with my decidedly poor photography.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...