Lost Art Press

Round the Corners of a Plane Iron

Posted on by Lost Art Press

If the corners of a handplane’s cutter are not supposed to cut wood, then I remove them.

OK, let me put that a different way. Some handplanes are supposed to cut into corners: rabbet planes, shoulder planes, moulding planes and router planes (to name a few). So these planes need cutters with sharp corners so they will cut sharp corners in the wood.

Other planes are supposed to cut surfaces and not leave any sharp corners: bench planes, block planes and scraper planes (to name a few). So these planes need cutters that don’t create sharp corners in the wood – what some call “plane tracks.”

One way to avoid plane tracks is to make the cutting edge curved, such as in a scrub plane or jack plane. Another method is to round over the corners of the iron. My preferred method is to do both. I round over the corners of the plane iron and then sharpen a slight camber in its cutting edge.

The combination of these methods greatly improves the way the wood looks after I plane it.

So how to you round over the corners? After I grind an iron, I remove the corners on a diamond stone. You can use any stone (or sandpaper). The diamond stone is simply more durable than a waterstone or sandpaper.

After rounding the corners, I hone the iron and put considerable pressure on the corners to curve the cutting edge and blend my edge into the newly rounded corners.

There are other ways of accomplishing the same goal. And I’m sure your method works better than mine. But this is what I do.

— Christopher Schwarz

13 thoughts on “Round the Corners of a Plane Iron”

  2. Wouldn’t one need to do one more pass with the back of the iron flat on the stone to insure there is no burr? Or would a burr never touch?

    1. Hi Barb,

      The polishing of the back at the end of honing removes any burr – both from rounding the corners and from the honing. For me, the last step before a plane iron goes back to work is to polish the back a tad. I hope this makes sense.

  3. I have little reason to change the way of doing anything you have taught me. I pass that knowledge on to my student.

  4. Thanks Chris. I have wanted to try rounding the corners (in addition to a slight camber) on my number 3 smoothing plane. The camber I know how to do (similar to what you mention). Wasn’t sure exactly how to round the corner. The video was helpful.

  5. Excellent tutorial. I think I heard you say in an interview that you do not like doing videos? Too bad, because all the clips I have seen from you are very good whether you talk or not in them. I like that they are very informative, concise, and often tinted with humour while at the same time being serious. Thanks again for sharing your knowledge!

  6. So…….when does the back bevel come in at the time you are rounding the corners off? Lol. Duckin…

    I do the same on the corners. Erases my tracks……

  7. Is the camber just kind of done as a backup or “just to be thorough”? What’s the advantage of both as opposed to just rounding the corners?

    1. Hi Luke,

      In my experience, just rounding the corners makes it finicky to get the iron balanced perfectly in the mouth. Having a both camber and rounding the corners makes it easy to get a plane setting that works and that there are no sharp corners digging into the wood.

  8. Thank you for this.
    Also, love this pre-emptive line: “And I’m sure your method works better than mine.”

  9. Do you have any experience doing this with bevel-up planes? I am curious if the different geometry would require a more extreme rounding.

    With BU planes, a more extreme camber is necessary to get the same apparent radius as a BD plane, so the corner rounding seems to apply as well.

    Of course… it may not matter in the slightest. I’m just curious of your thoughts on this.

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