What's the thinnest advisable 1084 for kitchen knives?

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Sprayman

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Hello;

I think my next batch of knives will be chefs/kitchen knives. I'll be using 1084; I know that's not an ideal steel for kitchen knives, but it's what I'm best equipped to work with.

So, how thin should I go? I made a few out of 1084 last year and they are a bit too thick to be useful for most purposes.

Thanks,

Sprayman
 
The type of metal (1084 in your case) will have nothing to do with desired thickness of blade. For the general size chef knife I'd think something between .080" and .100", and if a small chef (5 or 6") and wanting a real slicer, I wouldn't worry about .070", but would prefer thicker stock.
 
It's worth trying 15n20 if you want kitchen knives. You can find thin stock easily (.095) works great. It also resist rust much better. Just using my little forge I get great results maybe better than 1084.
 
0.100-0.110" is nice for a 6-8" chef. We're talking 1.5-2" high blade at the heel, FFG.
0.125" is totally doable for a big, wide blade, but you'd better grind in some distal taper (do that anyway). Totally doable. Trick is grinding it thin before heat, but not too thin because you're going to have to sand through decarb. The usual balancing act. I think a 1084 chef knife left nice and hard would be a fantastic performer. I made a 1084 usuba recently, and it sure does cut...

Think I figured the chemistry was pretty close to Hitachi Yellow #3.
 
I've used plenty of .070" 15n20 and as thin as .049"! Warping is sometimes an issue as the steel is so floppy during heat treat but usually easy to fix. The knife will flex so make sure your handle is well attached.
 
.... So, how thin should I go? I made a few out of 1084 last year and they are a bit too thick to be useful for most purposes. ...
As thin as it needs to be is the real answer.

I always advise first time kitchen knife makers that if they make the blade 25% to 50% thinner than planned, it will still likely be too thick. .060 is plenty thick for most kitchen knives. A big chef blade can be .100 to .125", but beyond that it is more than needed (excepting deba). I buy my kitchen blade stock in .090, .070, and .060".

Grab a micrometer and measure your favorite brand name kitchen knives. You may be surprised how thin they are.
 
I made a chefs knife using .060 1095 and love it
 
1/8",0.125" 1084 is what I used for a cleaver. tempered to Rc62, it was worked well for almost 6 years. how do you heat treat? if doing it yourself, I would get some 8670 or 80CrV2 in 1/16" to 3/32" thickness. if you want to stay with 1084, use some 2" wide for a nakiri clone or 2 1/2" for a deba or heavy work knife or 3" for a cleaver.
 
Wow, thanks for all of the helpful replies, guys.

I've always used coal, but on these kitchen knives, I am going to build and experiment with a 2-brick forge. I like to use 1084 because it's easiest to heat treat, in my experience; I use the magnet test.

I think the blades will be about 6'' long--more slicers than chef's knives. Flexible is OK, I suppose, but I am hoping to avoid warping during heat treat.
 
And another question:

I've looked online, and everyone seems to be out of the thinner stock of 1084. Is there another steel with similar qualities, that will be simple enough for the magnet test? I haven't had as much luck with 1095. What about tool steel or 15n20?
 
Tool steel is a generic, and pretty loosely defined, category. Most of the carbon steels we use to make knives can be called tool steel. True tool steels have alloying to make them suitable for specific tool use. D2, M4, O-1, L-6, HSS, etc. are properly called tool steels. 15N20 is called bandsaw steel or saw steel.

15N20 would work for your job with a home HT in a 2BF.

Do it like you do 1084 and it will make a descent knife. 1500F (a full shade plus a little brighter than non-magnetic) and get it all evenly heated along the edge (hold for at least 60 seconds if possible), quench in 130°F canola, temper immediately at 400°F, twice.

Before anyone points out that this is not the optimum regimen for 15N20, you are correct. But the OP does not have the equipment to do a 1475 soak for 10-15 minutes. The above method will make a suitably hardened blade. 15N20 has enough range of austenitization ( 1450-1550F) to allow for some overheating with no damage.
 
d6ONofN.jpg

This is a 12" Chef knife with .095 15n20. I had one or 2 others out of the same batch hit 62.5 Rc doing it like Stacy recommends. I have given several knives to friends and the are all very happy with the performance. I'm sure you can do better with a oven but I don't think you can do a lot better with 1084 without one. The one thing is that I was using new 15n20 from Aldo. I have used stock from JT but I think that's going to require a little more work.
 
Cocobolo. Camera angle makes it look small. It's close to 17" overall and over 2.5" at the heal with FFG to near zero edge. It's less than 7 oz but doesn't feel fragile.
 
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Very nice looking knife

skillgannon said:
d6ONofN.jpg

This is a 12" Chef knife with .095 15n20. I had one or 2 others out of the same batch hit 62.5 Rc doing it like Stacy recommends. I have given several knives to friends and the are all very happy with the performance. I'm sure you can do better with a oven but I don't think you can do a lot better with 1084 without one. The one thing is that I was using new 15n20 from Aldo. I have used stock from JT but I think that's going to require a little more work.
Click to expand...
 
daizee said:
0.100-0.110" is nice for a 6-8" chef. We're talking 1.5-2" high blade at the heel, FFG.
0.125" is totally doable for a big, wide blade, but you'd better grind in some distal taper (do that anyway). Totally doable. Trick is grinding it thin before heat, but not too thin because you're going to have to sand through decarb. The usual balancing act. I think a 1084 chef knife left nice and hard would be a fantastic performer. I made a 1084 usuba recently, and it sure does cut...
Click to expand...

^This... The classic French Sabatier chef's knives are well known for their tremendous distal taper. This characteristic was carried over to the French-influenced Japanese gyuto or double beveled chef's knife. For a wa (hidden tang) handled Japanese gyuto, some may even measure 5 mm thick (0.20") at the spine coming out out of the handle but are forged down thinner as you get closer and closer to the tip.

I personally am using 0.125" 1084 and 0.095" 15N20 from Aldo. I grind both down thinner than the initial stock to establish distal taper, but if you're forging then you can spend elbow grease forging in the taper rather than spending sanding belts.

Edited to add: Most commercially available chef's knives are now quite thin at the spine. A large part of that is due to modern manufacturing processes. If you're not going to grind in distal taper, a thinner knife will both slice easier and require less steel to make. If you're making handmade knives, distal taper allows a chef's knife to be thin towards the tip for fine slicing but thick towards the heel for chopping which increases the all-in-one utility of a chef's knife. This is in opposition to the Japanese style of one specialized knife for each task.

In my two brick, I've gotten slightly better chef's knife edge retention with 15N20 than 1084 using basically the same HT as Stacy recommends. Might just be luck depending on the what steel lot and HT on any given day. Since I work outside, I always do HT after sundown in the dark so I can watch the colors better but still check with a magnet too. If you watch carefully, theoretically you could catch the decalescence (the color change that occurs during the phase change to austenite) by eye, but I often don't end up seeing it due to the colors inside my 2BF and the desire not to stare in it too long (eye damage potential).
 
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Stacy E. Apelt - Bladesmith said:
Tool steel is a generic, and pretty loosely defined, category. Most of the carbon steels we use to make knives can be called tool steel. True tool steels have alloying to make them suitable for specific tool use. D2, M4, O-1, L-6, HSS, etc. are properly called tool steels. 15N20 is called bandsaw steel or saw steel.

15N20 would work for your job with a home HT in a 2BF.

Do it like you do 1084 and it will make a descent knife. 1500F (a full shade plus a little brighter than non-magnetic) and get it all evenly heated along the edge (hold for at least 60 seconds if possible), quench in 130°F canola, temper immediately at 400°F, twice.

Before anyone points out that this is not the optimum regimen for 15N20, you are correct. But the OP does not have the equipment to do a 1475 soak for 10-15 minutes. The above method will make a suitably hardened blade. 15N20 has enough range of austenitization ( 1450-1550F) to allow for some overheating with no damage.
Click to expand...

Thanks for the advice, Stacey. I've ordered some 0.95 15n20. So, once the blank reaches non-magnetic, you recommend leaving it in the forge for about another 60 seconds?
 
daizee said:
0.100-0.110" is nice for a 6-8" chef. We're talking 1.5-2" high blade at the heel, FFG.
0.125" is totally doable for a big, wide blade, but you'd better grind in some distal taper (do that anyway). Totally doable. Trick is grinding it thin before heat, but not too thin because you're going to have to sand through decarb. The usual balancing act. I think a 1084 chef knife left nice and hard would be a fantastic performer. I made a 1084 usuba recently, and it sure does cut...

Think I figured the chemistry was pretty close to Hitachi Yellow #3.
Click to expand...


Thanks, daizee. So should I grind the edge down to about the thickness of a dime before heat treat? That's the standard I've used in the past.
 
all of my normal kitchen knives start as .103-.113 its all about how you grind them this includes my paring knives. single bevels and some other heavy blades will be much thicker but i dont like using thinner steel due to flexing under the scales cna pop them (not off but then space for rust to form under the scales
 
"...........So should I grind the edge down to about the thickness of a dime before heat treat? That's the standard I've used in the past.

A dime is much too thick - .053". You want about half the thickness of a dime. Somewhere around .025-.030" is a good edge thickness for carbon steel at HT. Stainless blades can be .010-.015" at HT.
 
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