Sooo .... What's the "proper" edge angle?

[afishhunter]

What's the proper "general use" edge angle (inclusive) for an axe or hatchet used in the woods?
I can't find Kephart's or Nessmuk's preferance.

 

[SC T100]

I use the one provided in the An Ax to Grind manual. It works great, though getting that bevel correct on some blunt axes takes a lot of file work. At the end though, you have an excellent all purpose edge.

 

[Chignecto Woodsman]

Yeah, that gauge works well. It is originally from Woodsmanship.

There are also the exact angles used in "The Ax Book". This allows you to change things slightly depending on what wood you are cutting.

Generally speaking, the harder the wood is to cut, pop the chip, and how likely it is to damage the edge, the greater the angle and closer the bevel is to the edge (not necessarily the latter in the case of preventing damage).

If I remember correctly, it is 30* at 1/16" and 15* at 1/2" for Dudley Cook's recommendations, very close to that of Woodsmanship.

 

[300Six]

I use the one provided in the An Ax to Grind manual. It works great, though getting that bevel correct on some blunt axes takes a lot of file work. At the end though, you have an excellent all purpose edge.

Ditto. Most of us are more eager to use an axe than to sharpen it so take a file with you when you're out. Periodic filing beats the pants off devoting an entire afternoon to trying to do it all at once. As soon as it is pointy it'll work but achieving the ideal angle (for your purposes) is a whole other kettle of fish.

 

[killa_concept]

print off page 29 of this manual at 100% scaling

Glue to hard backing:

Cut out with box knife:

Unlike with knives, axes are more reliant on the overall profile than the actual edge. You can't simply judge how well an axe is going to perform based on the final inclusive angle. A well-established and sharp edge will help prevent deflection and aid in overall use (especially for finer tasks), but it's the thicknesses at various levels behind the edge that will determine how deep the blade penetrates, how much it sticks and how well it pops chips. The above gauge is a pretty good place to start.

My 3lb Keen Kutter Jersey (right) fits well into the gauge - maybe a bit thinner actually. It does a pretty dang good job on pine (what I mostly use it on here in the NW). Penetrates deep but can stick a bit if I don't deliver a strong enough swing.
The 4lb True Temper Connecticut (left) doesn't quite fit into the gauge (though I've since thinned the cheeks out more) but it's also quite the workhorse. It probably penetrates as deep as the Jersey, but mostly because of the extra weight. No issues with sticking though and it tends to blow out huge chips if I do my part. Also makes for a much better splitter as it widens out more towards the eye and has a higher centerline.

Since you're dealing with convex edges, the geometry isn't as exact and quantifiable. That gauge is a good place to start though. You can go thicker if the wood you're working with (hardwoods) or the job you're performing (possible knots + working closer to the ground) calls for it, but I honestly wouldn't go all that much thinner for a full sized axe. You can definitely go a fair bit thinner for a camp axe or lighter boy's axe though IMO.

 

[killa_concept]

I use the one provided in the An Ax to Grind manual. It works great, though getting that bevel correct on some blunt axes takes a lot of file work. At the end though, you have an excellent all purpose edge.

Ditto. Most of us are more eager to use an axe than to sharpen it so take a file with you when you're out. Periodic filing beats the pants off devoting an entire afternoon to trying to do it all at once. As soon as it is pointy it'll work but achieving the ideal angle (for your purposes) is a whole other kettle of fish.

"Give me six hours to chop down a tree and I will spend the first four sharpening the axe" -Abe Lincoln
I know everyone takes this quote as a good metaphor for the importance of planning and preparedness, but I'll be damned if it doesn't hold up in the literal sense. Taking a worn, blunt, or otherwise thick-cheeked axe and putting a proper profile on it (I stress the term "profile" over "edge") can be very time consuming and laborious. Not to mention that if you just use a 10-12" (made in Mexico) Nicholson double-cut or single cut mill bastard from your local HW store like I do, it's easy to entirely wear one out reprofiling such an axe. I swear my old American made Nicholsons lasted at least 2 axes...

I actually purchased my first Connie from a fellow member and while the thickness might have suited him, it was way too thick for me. Here's how I got it from him in I believe Feb or March of last year:

Then after one heavy filing session, which left it able to fit maybe 3/4th of the way into the gauge. Was just a bit too thick at the outer portion of the cheeks. Still did a solid job when I took it camping that year though:

And finally how it is now. Fits the gauge dead on at center and boy howdy does she blow out chips. Also thinned the handle down a good deal more and made a simple leather sheath:

 

[Steve Tall]

Interesting that two gages (one for softwoods and one for hardwoods) are shown in this U.S. Govt. publication from 1962:

From Logging Farm Wood Crops, Farmers' Bulletin No. 2090, U.S. Department of Agriculture, 1962
"...prepared with the specific suggestions and help of more than 80 qualified people throughout the country."


Has anyone seen an "explosive wedge" that uses black powder? (from page 13):

 

[Chignecto Woodsman]

Yes, quite interesting. Here is another image:
"Taper
The axe blade has a curved taper towards the edge. During sharpening it is important that the correct taper is maintained.
Heavy axes and axes used to cut hard wood and frozen wood require a stronger blade close to the cutting edge (1a).
Lighter axes and axes used for soft wood should be thinner close to the cutting edge (1b).
Although wood of coniferous trees is usually soft, branches may be very hard and axes may require the same taper as for hard wood.
Taper gauge
The taper of new axes is usually suitable for average conditions. A gauge can be made from a piece of metal sheet corresponding to the taper of the new axe (2a). This gauge can be used during maintenance. If the axe "bites", the taper is too small and if the axe does not penetrate enough into the wood, the taper is too big. Adjustments are made during maintenance and when the taper corresponds to the requirements, the taper gauge can be adjusted accordingly."

From:
http://www.appropedia.org/Original:Wood_Harvesting_with_Hand_Tools_4#MAINTAINING_AN_AXE

 

[Chignecto Woodsman]

Information I might be more inclined to agree with:

From: http://www.fao.org/docrep/016/t0129e/t0129e.pdf

Although this contradicts much of what we've learned from timbersports where the idea is to have a greater angle at the edge while moving the bevel forward.

From what I can tell, Dudley Cook's specifications conform to softwood and the Bernard Mason's gauge conforms to hardwood, if we compare them to the images shown here.

Further, Mors Kochanski recommends a thinner bit still for limbing. This may be only after the bevel, however, and this reasoning may throw a bit of a monkeywrench into the theories of the high centerline, as Gransfors Bruks advocates the same thin bit for limbing - which most of their axes are centered around (the Scandinavian Forest Axe is a traditional limbing axe, according to Gransfors).

Going to check a little closer into my gauge and distance/width later on.

 

[Chignecto Woodsman]

Another potential contradiction from a racing axe specialist:
"The Ossie is a conventional grind which has been shortened in the chisel and thinned to create a short fine chisel. This axe is not for the faint hearted, or for axemen cutting strong timber. Specifically designed for softwoods, an Ossie is at home in an arena of poplar and some pine species. Its thin short chisel creates little friction and so it penetrates the softwood well. Leave this axe at home if bound for Royal Sydney, but if the log steward has ordered softwood then a couple of Ossie axes might be the best choice."

"Bluey is one of the best performers in firm timber and is well suited to the Mountain Ash cut at Royal Sydney Show in Australia. A long flat chisel, the bearest hollow grind and medium size characterise this axe. Used for both underhand and standing blocks, it chips the hardwood well with good penetration. It is wide enough to cover a 14 inch log in two blows and yet still meets the size and weight limits for a hard hitting axe."

"USA Axes

These axes are specifically ground for the timbers cut in the USA which tend to be faster cutting than the Australian hardwoods.

These axes are ground with a 13.5 degree chisel and vary in chisel length from 12 to 20mm depending on the type of timber to be cut.

They are well suited to White Pine or Aspin Cotton Wood."

In this instance we have a very short chisel for the softwood axe, and a long chisel with very slight hollow for the hardwood. Although mountain ash is not what I would consider a very hard wood (but maybe it is an entirely different species there).

And all of the axe specifications:
Axe Specifications

Width
Length
Chisel Length
Chisel Angle
Blade Radius
Bust Radius
Grind

Quotes from:
http://www.osborneaxes.com.au/conventional_grinds.html

 

[Operator1975]

You can go off of books, fancy figures, angles, etc. Or you can sharpen it with a bastard file and then tweak it to your pleasure. Axes aren't about sharpness, they are about centerline, geometry, overall bite, etc. How specifically an edge is sharp will help, but will not ultimately tell the tale. A true woodsman knows this.

 

[Square_peg]

Sharpness is surely an important factor in how well an axe works. A true woodsman knows this.

 

[Chignecto Woodsman]

If an axe is not sharp it's a good way to send it into your foot, instep, or shin for a nice blunt injury. Even moreso with axes that have acute angles or in chopping where a shallow-angled cut is best.

 

[Operator1975]

Sharpness is surely an important factor in how well an axe works. A true woodsman knows this.

Sharpness is important, but not the most important factor. Case in point you can have an axe that a guy put on his grinder and sharpened to the point it will shave, and have geometry like that of a roof top. Or you can have an axe not as sharp, that wont be able to shave, and it will out perform that axe because it has the right overall grind, centerline, angle, etc. That is a fact.

 

[killa_concept]

Yeah I hate to admit it but if we're talking a general purpose work axe, I'm with Op1975 on this one. Like I said above: Unlike with knives, axes are more reliant on the overall profile than the actual edge. If we're talking something like a carving or broad hatchet/axe then yes, a well tuned edge is paramount. Otherwise a "serviceable" edge will do. No one here is recommending the use of a "dull" axe in line with what you'd find on most off-the-shelf hardware store axes these days.

Personally though, re-profiling is the tough part and once that's done I don't find it difficult to establish and maintain a shaving sharp edge. Even after felling, limbing, sectioning and then splitting a dead standing pine, it took all of 5 minutes with a hard pocket arkansas stone and some passes on my leather belt to get my 4lb Connie shaving again. Granted I didn't hit any crazy knots or ground/rocks so no real edge damage could have occurred. I'm sure if I wasn't just a recreational amateur and I couldn't baby my tools, I'd opt for more "serviceable" edges using just a file.

 

[Chignecto Woodsman]

Arden Cogar Jr. has written that the grinds don't really matter, they simply feel different in the wood and it comes down to personal preference of the competitor. That is an idea at the top of skill, sharpness, and geometry.

I suppose sharpness comes down to your own definition of it, but there's no doubt it is important. You can see how an unsharp axe cuts in the wood, tearing fibers rather than making a clean cut, if it cuts at all.

The first axe here is a good example of how an unsharp axe chops (not my video, but it is an Arvika comp axe, which are known to have something of a hardwood working grind on them, so it is grind, but a dull axe performs the same):
[video=youtube;spHqaokiL04]https://www.youtube.com/watch?v=spHqaokiL04[/video]

Take an unsharp axe and compare it to a swamping grind and it will perform much the same. Or compare how an axe with a worn toe cuts at each corner of the tree (the toe is already at a disadvantage, but still).

And again, if you're cutting between 30-45* sharpness is a huge factor in safety. If you're cutting at a steep angle, 45-60*, it's safer, but also severely limits cutting and chipping.

Further, it is largely skill and placement of cuts which prevents sticking. So given all this I don't see how anyone can argue against sharpness. Comes down to definitions, but it seems the argument is being made based on a comparison of a sharp axe with poor geometry vs. a nearly sharp axe with excellent geometry. The fair comparison would be a dull axe with excellent geometry vs. the sharp axe with poor geometry, or the nearly sharp axe with excellent geometry vs. the very sharp axe with good to very good geometry. And they would function pretty much the same.

Personally, I think it is nonsense to separate the two. It is like saying one can shave with their knife but it's 1/4" thick with a 30* angle. That 'knife' won't cut wood for shit. Cutting ability is the right balance of sharpness and angle for the material you want to cut.

 

[FortyTwoBlades]

Sharpness is simply a subset of overall geometry.

 

[ICS]

Sharpness is sharpness, it's not a subset of anything. If it's not sharp, it doesn't cut, simple as that. I can't believe some of the drawn out explanations and arguments regarding angles of bevel, length of bevel, hollow, flat, straight handle, curved handle and all the other idiosyncrasies associated with this magnificent basic tool. I say learn your craft well, know your timber, put it all into practice and don't be afraid to tinker with any or all of the elements, then when you think the combination is right, sharpen it and you will be amazed at the results. I also say put away the templates, profiles or whatever they are called and experiment, who knows, you may just come up with something we have all been looking for. Cheers, ICS

 

[FortyTwoBlades]

Sharpness is sharpness, it's not a subset of anything. If it's not sharp, it doesn't cut, simple as that.

What is sharpness if not geometry? It's just the geometry of a specific area--specifically sharpness is nothing more than the width of the bevel apex. You can get the edge of a steel cube as sharp as a straight razor but it won't shave the same way because the rest of the geometry is so radically different.

 

[ICS]

FortyTwo, for mine, I think they are two different things. Geometry of an implement comes first, that's why choose a pattern, length of bevel, forge, grind etc. etc. then we sharpen it. If we get the combination right it works a treat. I have said it before, simplify the explanations and you will see a lot more interest in people wanting to dabble with these magnificent hand tools. I know that honing or sharpening is a process we go through to refine the structure or "geometry" of the cutting edge but I have yet to hear someone say anything other than "that thing could do with a sharpen", not, "I think you should improve the geometry of that thing" keep it simple. Cheers ICS