Need advice on material for a custom knife build

[dubvee]

I’m looking to make a “panel testing knife” for a plywood manufacturing company’s quality control department. The knife is essentially a chisel that gets hammered in between the layers of plywood then used to pry and rip open the panel to gauge the bond levels of the glue. My first instinct was to use 5160 or maybe 1075. I can only do simple forge heat treats. I will be making quite a few of the blades so I’d like to be able to buy the stock pretty close to finished dimensions. What steels do you think would suit the needs of this build and how would you temper it. Thanks in advance for any advice.

(Also this is my first post so if I’ve placed this in the wrong place I’m sorry and I’ll relocate as soon as I know where to place it)

 

[tim37a]

Why not go to Lowes and get a Craftsman chisel?

 

[Lorien]

5160 seems like a good choice

 

[Seedy Lot]

80CrV2 woukd also be a good option.

 

[TheEdge01]

I’ll also add that 8670 would be a good choice. It has a simple enough heat treat. Temper between 350-400F 2x for 2 hours for 8670 and the aforementioned steels.

 

[dubvee]

Why not go to Lowes and get a Craftsman chisel?

You’re right why go through the trouble to make anything ?

 

[dubvee]

I’ll also add that 8670 would be a good choice. It has a simple enough heat treat. Temper between 350-400F 2x for 2 hours for 8670 and the aforementioned steels.

I was looking at the 8670 but I don’t know a ton about it. Is it a pretty tough steel ?

 

[dubvee]

80CrV2 woukd also be a good option.

I’ve never used 80CrV2 what in your opinion makes this a good candidate?

 

[Seedy Lot]

I’ve never used 80CrV2 what in your opinion makes this a good candidate?

From breaking coupons 80CrV2 has been the champ, even more effort to bend break than CD#1 or Pop's 8670.

Also 80CrV2 has been one of the easiest low alloy steels for me to heat treat.

 

[TheEdge01]

I was looking at the 8670 but I don’t know a ton about it. Is it a pretty tough steel ?

It’s a very tough steel. I’ve used it a lot and have never had any complaints. One person decided to chop bone with a machete I made and experienced no issues.

 

[velegski]

5160 , heat treated in along lines of Ed Caffrey's suggested heat treat for the ABS test knives. You can find that on his site. If you are using a hammer you might need to draw back or soften strike areas to prevent spalling or splinters from steel

 

[dubvee]

5160 , heat treated in along lines of Ed Caffrey's suggested heat treat for the ABS test knives. You can find that on his site. If you are using a hammer you might need to draw back or soften strike areas to prevent spalling or splinters from steel

Nice source of information there I appreciate it!

 

[Alex Topfer]

What's the bevel angle on these? If it's got a 45 degree bevel you might be able to go for a harder steel

 

[Stacy E. Apelt - Bladesmith]

I would recommend 8670.

HT for the edge and draw the temper with a torch down the entire blade and tang to a straw brown color.
Putting 1" of the chisel end under water while drawing the temper will keep the edge fully hard.

Normally, you would want a flared bolster on the transition from blade to tang. Since that isn't the way you will be making these, you want good shoulders on the blade tang junction, and a thick guard washer to take the blows and not drive the handle down the blade. A guard washer is a disc the size of the end of the handle that is slotted to fit the tang and seat on the shoulders. After assembly of the knife, you grind any excess of the disc flush with the handle.
Putting a ferrule/collar on both ends of the handle will also be wise. I would suggest 1/8" thick steel tubing for the ferrules and 1/8" steel for the guard washers. Turning the handles on a lathe will also be a good method of getting a uniform product ... and it makes adding the ferrules easy. Look at some quality chisels to get some ideas.

One caveat - if you are doing simple forge HT you really don't know exactly what you will get quality wise. These chisel knives will be for testing and should all be that same hardness and toughness. You might be better off to have the batch of blades HTed by someone with an oven.

 

[Alpha Knife Supply]

I agree with Stacey's recommendation to use 8670.

Not all 8670 is the same. Larrin's testing showed some 8670 to be significantly tougher than 80CrV2.

Chuck

 

[dubvee]

I would recommend 8670.

HT for the edge and draw the temper with a torch down the entire blade and tang to a straw brown color.
Putting 1" of the chisel end under water while drawing the temper will keep the edge fully hard.

Normally, you would want a flared bolster on the transition from blade to tang. Since that isn't the way you will be making these, you want good shoulders on the blade tang junction, and a thick guard washer to take the blows and not drive the handle down the blade. A guard washer is a disc the size of the end of the handle that is slotted to fit the tang and seat on the shoulders. After assembly of the knife, you grind any excess of the disc flush with the handle.
Putting a ferrule/collar on both ends of the handle will also be wise. I would suggest 1/8" thick steel tubing for the ferrules and 1/8" steel for the guard washers. Turning the handles on a lathe will also be a good method of getting a uniform product ... and it makes adding the ferrules easy. Look at some quality chisels to get some ideas.

One caveat - if you are doing simple forge HT you really don't know exactly what you will get quality wise. These chisel knives will be for testing and should all be that same hardness and toughness. You might be better off to have the batch of blades HTed by someone with an oven.

I appreciate all the solid feed back. So these chisel knives will essentially just be a pry bar. The blade it’s self doesn’t matter in the testing of the panel it’s more about how much wood fiber rips out with the glue so having slight variations in the HT won’t affect the out come of the testing that being said I still want to make the best product that I can. My idea was to essentially have the full tang extend a bit past the end of the handle and after heat treat do as you said and draw the temper back on it in that area. After someone mentioned the 8670 I did some looking into it. Its toughness seems pretty unrivaled with a simple normalization and quench. And considering these chisels will be hammered into the plywood edge retention and hardness are not my main goals I want something that will stand up to the abuse of being hammered without to much mushrooming. That being said I’ve only made knives for skinning and cooking so hardness was always my goal with tempering this how far back would you guys recommend tempering the business end of the chisel. What Rockwell should I shoot for low 50s ? High 40s

 

[dubvee]

I agree with Stacey's recommendation to use 8670.

Not all 8670 is the same. Larrin's testing showed some 8670 to be significantly tougher than 80CrV2.

Chuck

A lot of the information I went through on knife steel nerds agrees with that statement 8670 maintains a much higher toughness value due to the low carbon content. If I understood everything I read a normalized blade at about 1550 degrees Fahrenheit 5 min soak then 1300 air to black heat then hot non magnetic quench in oil (I’m using canola) that’s pre heated to about 120 degrees should yield great grain structure then temper it back 2 cycles 2 hours I’m not sure of the temper heat yet tho I want the toughness more than hardness.

 

[dubvee]

I would recommend 8670.

HT for the edge and draw the temper with a torch down the entire blade and tang to a straw brown color.
Putting 1" of the chisel end under water while drawing the temper will keep the edge fully hard.

Normally, you would want a flared bolster on the transition from blade to tang. Since that isn't the way you will be making these, you want good shoulders on the blade tang junction, and a thick guard washer to take the blows and not drive the handle down the blade. A guard washer is a disc the size of the end of the handle that is slotted to fit the tang and seat on the shoulders. After assembly of the knife, you grind any excess of the disc flush with the handle.
Putting a ferrule/collar on both ends of the handle will also be wise. I would suggest 1/8" thick steel tubing for the ferrules and 1/8" steel for the guard washers. Turning the handles on a lathe will also be a good method of getting a uniform product ... and it makes adding the ferrules easy. Look at some quality chisels to get some ideas.

One caveat - if you are doing simple forge HT you really don't know exactly what you will get quality wise. These chisel knives will be for testing and should all be that same hardness and toughness. You might be better off to have the batch of blades HTed by someone with an oven.

Does the flared bolster at the shoulders lend more strength to the structure? Like you said with stock removal that’s not really an option but I am intending on leaving it as thick as I can with out make it cumbersome in those areas to help avoid super weak areas. I’m also planing on making this out of .250 stock so it is robust enough to withstand abuse.