"Ting" Day...Help me troubleshoot please

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My brother came over wanting to see what all went into making a knife. Looking forward to spending time with him I worked on a couple of new (for me) patterns I wanted to do as well. The steel we were working on was 1095 from New Jersey Steel Baron. We profiled the blades, stamped them, drilled holes in his, hot punched mine, normalized, clayed, and then heat treated in brine. My brine set up is a old water cooler that I put enough salt into it that there is still at least 1/4" of salt in the bottom. First blade, his, I let the blade soak at critical for 10 minutes and quenched. Didn't hear a thing, but I took my sanding block that I keep around the forge and rubbed down the bevel...yep, one crack. As you can see, four more cracked up blades. Other than the hot punching on my handles, these blades were all stock removal blades and the edges were left between a dime and penny thickness at the edge. I reduced the soak time at critical down to 3 minutes on the last blade. The last blade I actually paused about 2-3 seconds before quench. I didn't agitate the blades. Help me trouble shoot this guys, did I leave the edges too thin? Didn't get any wavy edges. Did I try to bring the hamon down too close to the edge?

My luck with 1095 so far on knives (three razors are just fine) are 3 lived, 6 died. That's a tough ratio to handle.

FYI, these blades were my version of the Ken Onion Shun knives.

A couple of questions. Did you smoothen out the edge before HT?
I also notice the the knives are curve upwards significantly. Did you make them like that, or is that the result of the differential quenching?
If that is the quenching, that is pretty significant and will put a lot of stress on the edge. Try leaving the hardened part thicker. Also, you have to take the deformation into account when shaping the blank. The engle between the handle and the edge on the bottom 2 knives is so large that it has to be pretty hard to use them as a knife (stressful for the wrist).

No, I did not smooth out past 80 grit. The blades are shaped that way, just like the Ken Onion Shun that are rather expensive. I guess I will go thicker and smooth the cutting edge.

A fast quenching oil for 1095 would be recommended but brine is it is. Did you do an interrupted quench? 1095 leaves a lot of decarb so leave enough of meat. What's the thickness of the edge before HT?

Btw, how wide is the hardened part? If it is narrow, there is going to be a lot of stress on a very thin piece of steel.

Another factor could be the manganese content but I would suggest using warmed oil an a series of blades, then if those arent hard enough, cold oil, then, plain water. Brine really is not needed for simple steels.

I recently did 6 stock removal kitchen knives made from 1/16 inch 1095. Heated to non magnetic, and quenched in @150 degree F recycled McDonalds french fry oil. No problems, and nice and hard (tempered in my kitchen oven at 400F). Based on this, and the problems you had with brine, I'd recommend oil for 1095.

Just to be safe I only use water quenches on "W" series steels.
Everything else I use oil.

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Originally Posted by skipnord

I recently did 6 stock removal kitchen knives made from 1/16 inch 1095. Heated to non magnetic, and quenched in @150 degree F recycled McDonalds french fry oil. No problems, and nice and hard (tempered in my kitchen oven at 400F). Based on this, and the problems you had with brine, I'd recommend oil for 1095.

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Scott's using differential heat treatment to create a hamon. You want water quench for that in order to get sharp hardening lines.

Sorry my answers haven't been more understandable, but I was trying to answer by my phone as my computer was down a bit...come to find out it wasn't the internet service at all, was my router.

My goal for this order of 1095 was to make some knives and razors with a hamon. I blame Charlie for this by the way, he made it look too easy, I'm realizing how how silly a notion that was now. Things are slow on the job right now and I can't afford the big investment of fast oil. After a couple days, LOTS of thinking, & your guys input on these cracked blades I would say the key errors on these blades are:
1. Cutting edge left too thin. My batteries are dead in my micrometer, but I would say these were left too thin. I know better than this.
2. Hardened area of the blade should be left at least 2x thicker. Note that all of the cracks are where I took the clay down the bevel of the blade. The large blade with three cracks has about 4-5mm of actual hard steel from the bottom of the hamon to the cutting edge. This combined with the steel being a bit thin was just too much stress.

I did try differential quenching on the last blade, the "TING" was rather loud (comparatively) not muffled quenchant.

I'm by far done with 1095 steel and hamons. My armor of pride took a ding, but I'll get back out there and get it right. Lessons like this just make you truly "know" what to do and not to do. A day of work down the tubes in just seconds in the quenchant.

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Originally Posted by shooter74743

but I'll get back out there and get it right. Lessons like this just make you truly "know" what to do and not to do. A day of work down the tubes in just seconds in the quenchant.

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No matter how much info and correct answers you might receive, practice makes for the best experience. If we don't screw up things once in a while we never learn. Nothing really wrong with that.

For a knife of that type, I would leave 1/2" of hardened steel. 4 ish mm is not enough, considering that there is a huge amount of non hardened steel applying force to it.
The good thing though is you can just anneal those knives, remove the part that was cracked and try again.

Thats what I was thinking on the two large ones. Sure won't be the first blade to start out larger, only to end up smaller...:brunoisright

Haha. Yes I've made 7/8 razors that were going to be 8/8's :)
Knifemakers don't make mistakes, they make smaller knives.

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Originally Posted by Maximilian

No matter how much info and correct answers you might receive, practice makes for the best experience. If we don't screw up things once in a while we never learn. Nothing really wrong with that.

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Yes...if you are not breaking blades, you are not making enough blades.

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Originally Posted by Mike Blue

Yes...if you are not breaking blades, you are not making enough blades.

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Keeps my ego in check. I finish one, think I'm getting pretty good, maybe better than pretty good then I'll break a couple trying to straighten. It's a journey that only leads to more mistakes. That's kind of the beautiful part though. We'll never be rid of problems to solve.

There are all sorts of advice about mastering a craft. One famous comment about that was that a master simply learns to hide (or correct) any mistakes made in the final product better than a journeyman.

IMO opinion, having watched any number of craftspersons who qualify as masters of their arts, one observably consistent behavior that I enjoy is seeing them avoid the mistake in the first place. That is Mastery. Then again, they are human and if their fingers are not crossed just so, or they are not holding their lips just right, or the spouse is having a bad day, or a dead mouse floats to the top of the quench tank, all manner of mistakes (juju) occur regardless. LOL

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Originally Posted by Mike Blue

Then again, they are human and if their fingers are not crossed just so, or they are not holding their lips just right, or the spouse is having a bad day, or a dead mouse floats to the top of the quench tank, all manner of mistakes (juju) occur regardless. LOL

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I've learned that if I get signs that today is not the day to do something, I find something else to do.

Probably mentioned this before - ran into a knife maker in Colorado that said you had to quench blades North to South to avoid cracking. Just one more bit of folklore. Like the floating mouse, Mike.

That folklore "north to south" is dead wrong or we only have the meat of the story. My forge is aligned north/south as well as the quenchant tank (ice chest)...you wouldn't happen to know "the rest of the folklore story" would you? I think I missed something. Note: I didn't purposely align stuff that way, it just happened to end up that way.

It's just folklore. I'm sure someone that knows more than I do could come up with many more things like this - full moons, black cats, whatever. You "proved" this one doesn't work. What's really important is what can be replicated.

I think it was the pending "blood moon" (lunar eclipse) I saw last night...

I think some of the guys that made swords back the "dark ages" said a good fighting sword needed blood in the quench.

I really REALLY need to know more about this mouse treatment thing! Does it have to be a field mouse? what about a larger NYC mouse? Will going with a sewer rat be too much stress on a smaller blade?

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Originally Posted by Magpie

I really REALLY need to know more about this mouse treatment thing! Does it have to be a field mouse? what about a larger NYC mouse? Will going with a sewer rat be too much stress on a smaller blade?

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Yes the size of the mouse correlates with the density of the oil which has defined limits on the accuracy of expected outcomes for the section thickness of the blade being quenched. However, the Heat Treater's guide has not considered this variable in the performance of the usual cutlery steels and is of unknown metallurgical significance.

Generally it is best to screen out organic residue before heating a series of blades as the acquired temperature of the oil will increase the negative outgassing of the decomposing mouse/rat giving a residual minor flavor to the oil that has some durability over time (years) and to the local atmosphere. Some may consider this offensive and vacate the premises, neighbors have been known to complain due to the proximity generated by an urban setting, and the constabulary may investigate for missing persons. It can attract curious felines and may be used to bait those. Other smiths have been known to cultivate such odors to relieve them of the burden of too many curious visitors.