Recommendation? New hobbyist knife maker.

[Jacob K]

Hi guys, my name is Jacob and I am a new hobbyist knife maker. I have made a few knives already but haven't really known what I was doing. I guess I just got lucky with the knives I made so far. Here are some pics of past knives.

Two sashimi knives made from W2, differentially hardened.

1095 slicer, differentially hardened.


I recently made a knife but I noticed that the sharp edge doesn't last very long. I was hoping someone could possible help enlighten me on what I am doing wrong. I am using a propane forge.

I am currently working with 1095 steel and I do stock removal.

My basic process is to profile and grind the knife and leave about 1/16 inches on the edge. I then normalize 2-3 times, each time going to barely dull orange non-magnetic (at night time). Then I clean the blade up, clay it with refractory cement and heat it up to slightly past non-magnetic and quench in warm water. I file test, remove some scale then I temper in my oven at about 400F for one hour, two times.

I did this for the above knife and I sharpened it to 4K, stropped it on leather, but found that the nice refined toothy edge goes away almost immediately. The edge is still sharp enough to cut paper but feels very smooth compared to when freshly stropped. Is this a problem with perhaps overheating the blade before quench and bad crystalline structure?

I also just failed a quench and broke the blade to take a look at the cross section. Thought I would post it to see what you guys think and if the grain size is ok or too large.

The transition is there but I somehow feel that the grain size is not what it could be. Is it just that I don't have the equipment to precisely control the HT?

I know I have a lot of questions but I have read other similar topics on this forum and others but I haven't really seen any topics that address this particular problem clearly.

Thanks,
Jake

 

[R.C.Reichert]

The grain looks kinda large to me. The knives you posted look amazing though. Great work. Seems like a time and temperature issue, something a little off. Curious what the pros have to say

 

[Jacob K]

Thank you R.C.Reichert. Perhaps I am being too cautious and not bringing it up properly to temp and not soaking it.

 

[R.C.Reichert]

Thank you R.C.Reichert. Perhaps I am being too cautious and not bringing it up properly to temp and not soaking it.

I honestly have no clue, we'll let the experts on this chime in. Why you would be getting grain enlargement without forging (and it doesn't sound to me like you're overheating) is interesting. All I know is 1095 can be tricky to get right with rudimentary methods which is why I avoid it. Makes me wonder if it's possible to acquire steel that has pre-existing large grains like that? Note that they "seem" large to me. You can see the individual grains with the bare eye which to me seems large. I found this picture online which shows what different grain structure looks like at different stages.

 

[Jacob K]

Well those pics are a close-up, by naked eye, they seem like fine sand, larger coarser grain on the edge and smaller grain towards the spine, past the hamon.

 

[Jacob K]

Actual grain size looks closer to this in real life:

 

[R.C.Reichert]

Well those pics are a close-up, by naked eye, they seem like fine sand, larger coarser grain on the edge and smaller grain towards the spine, past the hamon.

I think I might have had this happen to me before when I got the edge too hot on a blade. Now I always try to slowly heat up the spine first, but that's just what works for me.

 

[R.C.Reichert]

Out of curiosity I snapped the tip off one of my (junk drawer of failures) blades to see what the grain looked like. This is what I got. I think pictures can be deceiving. The left side of the blade on the first pic looks more grainy, but I think that's because of the direction the blade broke. It didn't want to break easily. Had to put all my weight just on the tip.

 

[kuraki]

You say you normalize three times. Normalizing is a single heat past critical, usually 1600f that puts everything back into solution.

Grain growth occurs with time and temps over critical.

The subsequent thermal cycles most of us do after the normalizing heats are generally stepping down in temperature below critical temp, say like this- normalize at 1600, thermal cycle at 1500, again at 1450, and again at 1400. These post normalizing cycles refine and reduce the grain size.

Large grain will produce edges that are hard but do not perform as well as a fine grain edge.

 

[Jacob K]

Ok that is great advice, that is exactly what I am doing wrong. I think I am finally beginning to understand the difference between normalizing and thermal cycling. As far as successfully accomplishing these steps, would you say that bringing the steel to orange for first thermal cycle is bad? I was thinking of going to orange, then red, then barely red for thermal cycling. Also, I shouldn't let it cool to room temp between cycles right? Thank you kuraki.

Thank you for the pic R.C. I feel that the grain size of this failed blade is not as fine as yours so I still have a lot of room for improvement.

 

[kuraki]

When I'm thermal cycling I inevitably cool to room temperature between heats because it takes me 10-15 minutes to get the furnace I'm using cooled down. They can be put back into heat after they've cooled to black, I don't think cooling further is a negative.

Color is very subjective. In my mind's eye orange is too hot, and to me it would be reddish orange, red, and faint glow for the last heat.

I didn't address soak. I soak for a few minutes at the normalizing temperature, but in the thermal cycling, I only leave it in heat until I feel it's reached the target temperature.

 

[Jacob K]

I see ok that makes a lot of sense. You soak at normalizing, around 1600 or orange for 5-10 to get everything in solution and evened out. Then the thermal cycle temps don't nees to be soaked, the actual temp matter more for that process. Does that about sum it up?

 

[C_Claycomb]

Based on my experience heat treating O-1 tool steel in a forge, that OP blade looked pretty coarse. Not as bad as something I overheated, but not as fine as it could be with that gear. There were once some great threads on here by Mete and Kevin Cashen about heat treating, multiple quenches, normalizing, soak times, alloys, all the good stuff. Just checked my records and the threads I was thinking of were back around 2005. I proved to myself that with my gear, performing three quench cycles got me finer grain and harder steel, but I wasn't able to hold a soak like you are meant to for O-1, so more quenches were a semi-work-around. Might be worth trying for the 1095?

Maybe some good stuff here:
http://www.hybridburners.com/documents/verhoeven.pdf
I would download it since it seems never to stay in the same place, I think this is the third or fourth place I have found it, not available from the older sources any more.

Good luck

Chris

 

[Jacob K]

Thanks Claycomb this is a great read. I have tried doing 3 full thermal cycles but with mixed results, partly because of inconsistent heating (gauging by color) and I was working at a piece with an 11 inch blade.

Here are the results. On the left side is the knife I posted above with fairly coarse grain, and on the right side is the one I attempted today with 3 thermal cycles. I heated to orange and tried to hold for about 3 minutes, then took out and air cooled to room temp. then heated to bright red, red, then barely glowing red. Both pieces are not tempered and just snapped to see the grain.

The grain is finer and barely visible to the naked eye, but I feel that it can be refined more. Am I just wasting my time without precise temperature control? Thanks for any input.

*Added* I broke another section of the blade closer to the middle and it revealed this structure.

Even under magnifying glass, the edge portion grain size is very hard to make out, meaning that the grain is very refined. So evidently the method works, it's just that I'm shit at it lol.

 

[R.C.Reichert]

Why so many thermal cycles if you're just doing stock removal? In the past whenever I've done stock removal blades from bar stock, I just do a single heat by heating the blade a shade past non-magnetic and straight into the quench with it. I never bothered with thermal cycles or even normalizing (which are necessary for forged blades) and my blades turned out with pretty decent crystal/grain structure. Assuming the bar of steel started out with a relatively decent grain to begin with, I wonder if you're just somehow overdoing it? In other words, maybe you just overcooked that goose? I don't know, lol...just a thought.

 

[R.C.Reichert]

Another thing you can try...or it's at least something I would try personally...is a different steel like 1080 or 1084. See then if the same thing persists or not.

 

[Jacob K]

I buy my steel from Jantz and it comes annealed. From what I've read online, the finer you can get the grain the better the edge and surface hardening. Perhaps I am just wasting my time doing 3 cycles. But I know for sure that on previous blades I had a less than ideal heat treatment.