How To Sharpen An Axe

I have been asked a number of times recently to provide some advice of guidance on the best way to sharpen an axe. Whilst I am always happy to provide input, I thought that it might be worthwhile to put together a tutorial on the basic techniques.

The techniques used in here are intended to provide not only a sharp axe but also a safe and efficient axe. Before we begin, its useful both to define the terms we will use and also to examine what we are setting out to achieve.

Parts Of The Axe

Below is a "jargon key" to the parts of an axe


A: Heel of Head
B: Bit
C: Toe of Head
D: Cheek or Ramp
E: Poll
F: Neck
G: Belly
H: Shoulder
I: Toe of Haft
J: Heel of Haft







C: Toe of Head
E: Poll
K: Eye
L: Wooden Wedge
M: Metal Wedge






Axe Geometry

Its important to understand the shape of an axe and why it is that shape. Firstly, lets examine the types of grinds that exist


Most axes designed for splitting and chopping are convex in profile (although certain specialist side axes and broad axes may be flat ground for shaping). The reason for giving and axe a convex grind is that it protects the cutting edge from damage.


As you can see from the illustration to the left (click to enlarge), due to the curve on a convex grind, the bit (cutting edge) of the axe head is not in contact with the wood after it has penetrated and in fact it is the ramp (side of the head) that is forcing the wood apart. This protects the cutting edge from damage and wear. It also explains why ensuring the ramps of your axe are smooth and polished will aid cutting efficiency





The next important point to consider is the shape of the bit. The vast majority of axe bits are curved (there are exceptions like carpenters axes). The reason for the curve is to aid penetration.

If you look at the illustration to the right (click to enlarge), you can see that, due to the curve, only part of the bit is actually in contact with the wood. The curve of the bit means that a small part of the bit is in contact with the wood when the axe first strikes. This begins the cut and as the contact point penetrates, more and more of the bit is introduced into the cut.

By beginning the cut on a small contact area, tremendous force is brought to bear in that area. It is also the area that is likely to blunt most quickly.

Hopefully this short explanation explains why it is important when sharpening to keep the profile convex and the bit curved.

Safety

Sharpening an axe is awkward, difficult and dangerous. You are forced to grip the axe in strange ways, apply pressure with a file to a curved surface that can cause the file to skate and slip etc.


Wear Gloves! Tough, cut proof gloves at that. Your tools will slip and you will cut yourself. Axes are designed to chop through hardwood. Your flesh will provide no resistance and your bones not much. I use Kevlar cut proof gloves, but if you are on a budget I suggest tough "rigger" gloves. But always, always, wear them



The technique for sharpening an axe is different to sharpening a knife. When sharpening a knife you often move the knife over the sharpener (particularly with bench stones etc.). When sharpening an axe, you always move the sharpener over the axe. This means the axe should not move and its mostly your hands that are at risk. Despite this, do not sharpen in your lap. A cut to the femoral artery will kill you. If at home, sharpen at a table with your legs underneath. If in the field, kneeling and keeping the axe head high is safest.

Sharpening Equipment

I wanted to show the stages of sharpening using both "purpose made" and "widely available" equipment. This will make this a slightly longer process, but its important to me that people understand you don’t need to use professional equipment to achieve professional standard sharpening.

Pictured to the right (click to enlarge) is the "Gransfors Bruks" sharpening system.

It consists of:

• An axe file
• A diamond file
• An axe stone with coarse and smooth sides

These tools allow for four stages of sharpening that we will examine later

Pictured to the right (click to enlarge) is a sharpening system that can easily be assembled in a hardware store for less than the price of one of the Gransfors Bruks tools. Not as compact as the Gransfors tools but no less efficient.

It consists of:

• A coarse crosscut file
• A fine metal file
• A set of diamond hones (these are an alternative to the fine metal file)
• A sanding block
• A block of buffing compound

In addition to these tools, a variety of grades of "Wet and Dry" abrasive paper and some scrap leather will be needed.