Sharpening a Plane Blade

I recently received an email from someone asking about my methods for sharpening my chisels and plane blades etc, so I thought it would be a good idea to grab my camera next time I do some sharpening and cover the subject in a blog post.

 

After using a whetstone grinder for the last couple of years (and oilstones before that), I made the switch to using waterstones (plus a diamond stone) earlier this year.

The ceramic waterstones I use are made in Japan by Sigma Power. They're not cheap, but they cut faster, stay flatter and are a lot less messy to use compared to the more budget friendly, non-ceramic waterstones on the market (King/Ice Bear etc). I use 3 grits, 1000/6000/13000. The 6000 grit stone produces a nice sharp edge, which is fine for most general work.. the 13,000 grit stone although not strictly necessary, takes it to another level.

To keep the waterstones flat I use a 400 grit Atoma diamond plate. I also use this if I need to restore a damaged blade or chisel before sharpening. I can't recommend the Atoma enough.. it's almost impossible to clog, cuts fast, and unlike most diamond plates it's made from stainless steel and aluminium, so no worries about rust.

When I ordered the stones from Tools From Japan, I also brought a Suehiro tray, which does a good job of keeping the water off my workbench.

Although the Sigma Power ceramic waterstones don't have to be soaked before use, I find that they do benefit from a quick soak (less clogging), so I leave them in water for a few minutes before I start work. The first job is to flatten the waterstone using the diamond plate. This only takes about 10 seconds.. drawing some pencil lines on the waterstone is a useful guide, when they've disappeared you know it's level.

To make this more informative, I've chosen to use a brand new blade. Typically, this is the only time the back of the blade will need to be flattened.

To flatten the back I begin with the 1000 grit stone, using a thin (0.4mm) ruler on the edge of the stone, which raises the angle up so that only the edge of the blade (the only bit that matters) is being flattened. I work the blade from side to side, keeping roughly within a 10mm distance from the edge of the stone.

I regularly check my progress, until I have a flattened strip across the full width of the edge (nearly done in this picture, just a bit left in one corner). For a 1000 grit stone, it cuts very quickly and does the job on this particular blade with ease. If I feel like it's taking too much time, for example on a wider blade, or a blade which isn't very flat to begin with, then I'd use this same procedure on the 400 grit diamond plate first, to speed things up.

Using the same method, I follow the 1000 grit stone with the 6000 and then 13000. The back now has a flat, polished strip all the way along the edge. The mirror finish isn't for show, failure to remove the vertical scratches left from manufacturing, will result in a serrated edge.

Next, I set my honing guide to 25 degrees, and slide the blade up to meet the guide block. I then pinch the blade against the jig, flip it over and tighten the two thumb screws. It's vital that the thumbscrews are tightened with equal pressure, clamping one side down too hard can result in skewing the blade in the guide.

With the blade held firmly in the honing guide, the registration jig is removed..

One thing I always check before honing the bevel, is that the micro bevel adjuster knob is set in the off/upright position.

On a well ground blade honing doesn't take long at all, again.. if I'm working on a damaged blade, or perhaps changing the bevel angle, then I'll start on the diamond plate before going to the 1000 grit stone.

These stones work best when damp, not dripping wet with water. The odd squirt of water is all that's needed. If they become noticeably clogged up, then a few swipes with the diamond plate does the trick.

Nearly there, you can see the scratch pattern changing..

When finished, you should feel a small burr (wire edge) all the way along the edge, on the back side of the blade.

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Now it's time to create the secondary or 'micro bevel'. To do this, I turn the micro bevel knob to the down position, which raises up the angle of the blade. I take 10-20 backward swipes on the 6000 grit stone, and then the same on the 13000. This results in a mirror polished strip at the very tip of the blade. The beauty of the micro bevel is that it can be re-honed quickly when the cutting edge starts to dull, without having to hone away at whole of the bevel. Therefore saving a lot of time and effort.

With the blade removed from the honing guide, the final step is to remove any burr left on the back of the blade using the 13000 stone. Again, using the ruler trick, I take a couple of gentle swipes, and that's it.. the blade is now ready to use.

To demonstrate the freshly sharpened blade, I started off with an off-cut of Tulipwood (Poplar), which produced nice wispy shavings, thin enough to see through.

To be fair, Tulipwood is fairly easy to plane, so for more of a challenge I put a piece of quilted Maple in the vice, and planed the end grain. The finish came out silky smooth, with zero tear out.

So there you have it.. that's my method of sharpening, it works well for me.

If you're looking into buying your first sharpening kit, then you'll no doubt discover that there's a lot of different methods out there... oil stones, waterstones, grinders, diamond plates, lapping films, etc. The internet is also full of self proclaimed experts, who love to argue the reasons why their chosen method is far superior. My advice would be to do your research, ignore the bullshit, and find a method which works best FOR YOU.

Feel free to leave any questions in the comment section below.