80CRv2 cleaver heat treat question

MBB

MBB

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Apr 18, 2014
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Howdy!

A friend asked if I would make him a western-style cleaver for cutting up deer carcasses. I had a length of 3" x 0.25" 80CRv2 from Aldo so I agreed to do it as a learning experience/freebie as I hadn't used that steel before. Cleaver's shaped, bevels ground, etc. at this point and I normalized 1600/1550/1500 F followed by a 1200 F x 1 hour stress relief cycle because I'm nervous about warping. The spine of the cleaver is still 0.25" with a primary (chisel grind) bevel to 0.125" and then a chisel grind from there to the edge. For the actual heat treat, I'm not sure which formula to do. I've seen 1500 F x 10 minutes with quench in a medium oil (11 second McMasters or 130 F Canola) and 1475 F x 10 minutes with quench in Parks 50.

Any help would be appreciated!

Mike
 
Treat it like 1084 with a little soak. I quench it in natural oils warmed to about 100-105°, from around 1500° or so. I've used this steel a lot, and it will easily chop bone and not deform if your edge geometry is on and tempering is done correctly for the application.
 
What tempering temperature/HRC would you shoot for? This is a heavy, brute force tool made for hacking.
 
I has playing around with steel recently, and was trying to use the Parks 50 but was getting large grain. After talking with Kevin Cashen I learned this is a deep hardening steel and needs the slower quench of the 11-second oil. I had done some with thermo cycling (1600/1500/1400) and some without. I ended up with 1500 for 10 minute soak, and into the McMaster Carr 11-second oil. I ended up with very nice even grain. It looked like porcelain. I saw no real difference between the thermo cycled or non cycled.
 
Thanks!

My concern with normalizing was that it was highly spheroidized, as I've read some posts where people had difficultly with hardening.
 
Too late on this build, but a single bevel on a heavy cleaver is not optimal. Heavy chopping blades generally do best with equal bevels. Many large deba are double grind. Thgese are often referred to as yo-deba ( western deba)

Thin cleaver looking blades for slicing and dicing veggies are often chisel grind ( katakiri-ha). Smaller deba are usually of this grind, too. These are often referred to as nakiri or "Chinese cleavers". They are not used to chop things harder than cabbages.
With a .25" spine, it appears you are making a break down chopper, which is a true cleaver. I like hira-zukuri blade (double grind to the spine) that is un-tapered for most of the side, curving into an appleseed grind ( convex grind) over the last 1" of the blade to the edge. This gives maximum weight and makes the edge strong for chopping and striking bone without edge deformation.
 
Thanks, Stacy!

This is a learning experience for both me and my friend, so if it fails, I'll try again. In response to your post, does the convex grind effectively increase the angle of the edge? Post grinding, I'm at 15 degrees at the chisel edge, which I was going to attempt to correct with a 10-15 degree microbevel. Also, what would you temper to? 59-60 HRC or 55-57?

Thanks again!
 
Cleavers are sharp axes for meat. Axes don't cut things. They make a cut and split ( cleave) thing along the cut line.
On a meat cleaver, the edge needs to be able to break/split bone. A convex edge enters at a fairly thin edge, and shortly later is much thicker. This pushes the item being severed apart, taking much of the energy of the blow and putting it into the thicker part just beyond the edge. Flesh will just move to the side, but bone will sever by splitting along the cut line. This makes the cleaver edge survive in striking bone. The katana edge geometry is for the same reason.

A very low angle (10°) and a straight bevel ( single or double) of a low angle (15°) will put most all the force on the very edge. That will work great if it only goes through softer things, but that edge will chip out and dull rapidly if striking bone. Those angles would be fine for slicing meat or cutting veggies, but would not last in chopping.

Meat Cleavers are sharpened at 30-40°.
"Chinese cleavers" For soft meats and veggies) are sharpened at 15-20°

Here is how to shape the edge on a cleaver:
Set the edge at an angle or 45°. ( 22.5° per side)
Do the secondary or edge angle at 30° (15° per side). We can argue primary vs secondary nomenclature at another time)
Convex the two into each other.

Silly but true - I once made a cleaver and deeply etched a beaver on it (using David Boyes acid etch technique). You either get it or you don't.



OT:
An interesting thing about the word Ax (now also axe) is that it is one of those words that has no base root. An ax is an ax. It became ax when some cave man asked another guy what that rock on a stick he had was called and is the same since. It clearly came from a proto-German source ( Neanderthal?) and is the same word in languages from Mongolian to Swedish.
Other languages that use different names for the tool, and have no relation to the Germanic proto-word. These languages use descriptive words that mean to hack. cut, chop, etc.
 
Nice! I appreciate the linguistics lesson and the cleaver information. I did a lot of hand tool woodworking in the past and plane blades are usually 30-35 degrees to prevent edge rolling/chipping, so that totally makes sense.

I'll probably start a second one while finishing this one out for lighter duty. I'm going to practice dowetailed bolsters on it.

Any input on steel choices? Would you go with 80CRv2 again or something else like 1075?

Thanks again!

Mike
 
Nothing wrong with 80CrV2. 1075 would be good for a hamon. I suppose S7 and 5160 would work good, too.
 
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