I could use some help identifying the flaw(s) in my plane iron sharpening technique… when honing a microbevel, the microbevel doesn’t want to “make it” all the way to the edge of the iron. It looks like the edges just don’t contact the stone… like the iron has a camber to it even though there shouldn’t be one.
I started again from scratch to see if that would help. I reground the iron, checked it for square, flattened my 1000 grit waterstone, and used my Vertitas Mark II honing guide (straight roller), and I got the same results. I am seeing this on all irons I sharpen including higher end irons like Lie Nielsen or Veritas.
Any ideas what might be going on?
Replies
You didn't mention flattening the back of the blade, but since you say it happens with all your blades, including Lie-Nielsen and Veritas, whose blades are shipped pretty flat to begin with I would think the problem lies elsewhere. The common denominators are the stone and the Mark.II, which I also use. Barring damage to the Mark.II, I would suspect the stone. You say you flattened it, but sounds like it would be domed or the opposite of typical stone wear. Have you put a straight edge across the stone? If so and it is truly flat then I can only suggest it might be your technique and how you are applying pressure to the blade. If you are applying too much pressure to the center it might cause this problem to occur. I try to maintain even moderate to light pressure across the blade. If you are using heavy pressure focused on the center it would tend to grind the blade in such a manner. Also try sharpening only on the pull stroke this might help as well.
Are you doing the primary bevel on a coarse stone, and then the micro bevel on a finer stone, each time you have this issue? Maybe you are taking a degree or two off the bevel, instead of adding, when doing the microbevel.
Esch may be right - you could have a water stone that isn't flat .... although how you would make one domed is something of a mystery, if so.
You can make a comparison test by making your edge and it's micro-bevel on something you know is flat, such as a diamond "stone" or some micro-grit "paper" on float glass. If you can make a straight edge and full-width micro-bevel on one of those, it must be your water stone that's causing the problem.
What do you use to flatten the water stone? As Esch suggests, test the water stone but also whatever you use to flatten it, using a straight edge. Just in case .... test your straight edge for straightness with another straight edge! (Kidding).
Can you post pics of water stone and the problem edge / micro-bevel?
Lataxe
Thanks for the ideas. I just posted some pics above.
Thanks for the reply. I had the same thought about the stone being domed somehow, but it always checks out flat after lapping on float glass. I'll give the pull stroke only approach to see if that makes a difference. I'm just about convinced that this is a technique issue, but I'm struggling to pinpoint it.
These pics (sort of) show what I'm seeing, but these are the "after I've tried to fix it" pics. The waviness is a result of me trying to correct the issue by applying a lot of pressure to the outside edges.
How are you grinding your primary bevel. It looks like you're grinding the ends slightly more than the middle portion, assuming the waterstones are flat. Still, looks like you have enough microbevel for the iron to work well.
You can make some marks across your bevel with a sharpie then sharpen with your current set up. You'll be able to see where you're taking off by where the marks are being removed. You can figure out what's going on a lot easier at this point and make the corrections to remedy it from there.
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