Woodworking Tips
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Sharpening Chisels, Part 2
Here's the second part of our two-part series on sharpening chisels. Last week, we ground the bevel of the chisel using a bench grinder. That gave us a hollow ground bevel -- the bevel reflects curve of the grinding wheel. This week we'll work on the cutting edge.

After grinding the bevel, you're ready to move from the grinding wheel to the stone. To hone a tool that's been hollow ground, I use a 1,000-grit waterstone. I like to use waterstones because they cut very fast. The 1,000-grit waterstone (a "medium" grit stone) will hone the cutting edge to a mirror finish.

When you've finished grinding the bevel, you'll notice that the grinding wheel raised a burr along the back of the cutting edge. So the first step is to remove that burr. To do this, hone the back of the last inch of the chisel flat on the sharpening stone.

After removing the burr, you're ready for the final step: honing the cutting edge. But why hone it? After all, you've probably got a really sharp edge already. The answer lies in what makes an edge last a long time.

If you take a close look, after grinding the bevel, you can see marks left by the wheel. Magnified, they look like deep grooves. These create a ragged cutting edge that feels sharp. But it doesn't stay sharp because the points on that ragged edge break off easily. The more they break, the more ragged the edge becomes, making it duller faster -- a sort of snowball effect.

To make a long-lasting edge, you'll need to remove that ragged edge. The smoother you get the cutting edge, the longer the edge will stay sharp.

To hone the cutting edge, hold the hollow ground bevel against the waterstone so both the front and back edges of the bevel touch the stone. Then gently push the bevel over the stone. You can push from end to end or make little arcs. Just do what is easiest for you to keep both the front and back edges of the bevel on the stone.

How long do you hone? Well, not long. Just until the grinding wheel marks along the cutting edge disappear. Then check for a burr on the back of the cutting edge. When you feel a burr along the whole cutting edge, hone off the burr (like you did with the burr created by the grinding wheel), and your chisel is ready to use.

One of the really nice things about this technique is that touching-up the edge after use is really quick. This is because you don't need to re-grind the bevel, just re-hone the edge. You should be able to touch-up the edge several times before you need to re-grind a new bevel.

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