Honing after hollow grinding

[Jack Dover]

This is spot on and exactly how I sharpen on the tools that I do employ a convex grind. It's a big source of confusion when talking about bevel convexity. I never leave a hump in the middle, and will remove such a hump on any tool that crosses my path, be it a chisel or axe.

I think a relieved heel appeared as a remedy for the primary angle becoming too steep eventually. It might be just fine for Paul, because the type of joinery he prefers is mostly chopping — compare it with, say, Japanese or Chinese joinery where a joint has tons of precisely pared surfaces and where absolutely no joint lines are allowed to be discernible (if only by the grain direction), — so a high angle makes sense. Plus, the Aldi chisels he seems to praise so much just don't hold the edge at 25, they fold over, even in pine.

My problem with rounded bevels is that any amount of rounding makes controlling a bevel down cut almost impossible on long cuts like sliding dovetails. A chisel tends to cut at an angle to a direction we want it to go (wood resistance, wedged shape, etc.), rounding reduces bevel registration area, so a chisel tends to always dig in. Yeah, there are routers and planes, but I can pare almost perfect surface with a flat bevel, so why wouldn't I? Other than that and the angle climbing higher and higher I can't think about other issues.

I can't stand rounding near the edge or a bulge in the middle even on axes and the like. If I want a higher angle, I just regrind the whole bevel at a higher angle and, again, relieve the heel.

Grinding does solve all kinds of issues, doesn't it? I just think that Paul pushes all this "you don't need this, you don't need that" a bit too far. It feels like in a few years he'll go full bushcraft mode and start advocating a stone axe as the only tool that is actually needed.

[steven c newman]

Have 2 sets of those Aldi's chisels....all are at 25 degrees....and haven't seen any "folding" yet.....what am I doing wrong?

[Jon Snider]

J.A.S.T. (Just Another Sharpening Thread)

Thanks. Insert sarcasm font.

As I said, I posted this after reviewing Neanderthal threads back to 2010. Due diligence done. I’m on page 707 right now (counting up to the oldest page, currently 989), and haven’t seen any direct question of what happens after hollow grinding before. Granted I might have missed it. It seemed a legitimate question to me which might help me in my shop. Sorry it was not the same for you.

[Jim Koepke]

Thanks. Insert sarcasm font.

As I said, I posted this after reviewing Neanderthal threads back to 2010. Due diligence done. I’m on page 707 right now (counting up to the oldest page, currently 989), and haven’t seen any direct question of what happens after hollow grinding before. Granted I might have missed it. It seemed a legitimate question to me which might help me in my shop. Sorry it was not the same for you.

Jon, yours is a legitimate inquiry.

In my experience, what happens after a hollow grind is there are two points of contact between the bevel and the sharpening media. This makes it much easier to feel the bevel register on the sharpening media whether it is a stone, abrasive sheets or a brick.

Some of us use disk grinders or belt sharpening systems and do not have the freehand advantage a hollow grind provides.

Eventually after a number of honing sessions the the bevel on a hollow ground edge will become a flat bevel. Then one either has to learn to hone a flat bevel or return to the grinder to reproduce the hollow grind.

When a thousand are people discussing sharpening, there are likely to be three thousand methods proclaimed to be the best way.

jtk

[Edward Weber]

Well said Jim
Also I believe, that "after a hollow grind is there are two points of contact between the bevel and the sharpening media" this is called the chord angle

[Tom M King]

We use guides for most things, mainly so my helpers can sharpen, and everything is kept at it's own specific angle. No microbevels. All flat honed bevels. All grinding is hollow grinding since we use round wheels, and use the perimeter of the wheels to remove metal when an edge is damaged. The ground bevels (hollow) are ground a degree or two (not measured) sharper than the cutting edge I want to end up with, just to get it out of the way. Only the cutting edge is honed on stones.

The sharpened bevels gradually take over the face of the bevel, for as long as it lasts before getting damaged enough to need grinding again. I don't think any of my finishing plane irons have seen a grinder in years-maybe even ten years, so all the bevels have long since taken over the whole face of the bevel.

Chisels get used for all sorts of things, so they see a grinder much more often. I think my paring chisels haven't seen a grinder any more often than my plane irons do.

[James Pallas]

Jon, Jim Koepke tells it right. Derek does a lot of grinding too. For myself I did my hollow grinding with just a grey wheel. Ivdid get a CBN wheel a couple of years ago. I don’t grind as a habit. If an edge is chipped or really bad I do grind. I than use the two edges to jig the honing. I side sharpen along the stone. The hollow grind will disappear after a while. I just continue sharpening the whole bevel unless it gets bad. I do strop often to keep a clean edge. I have tried hollow grinding more often when it starts to go away. I don’t think its any faster than just honing when needed. I have to put the grinder on the bench get a cup of water, grind, than go to the stone to hone. Than put the grinder up, clean up the dust, you don’t want that stuff around your tools. It is handy to have two points to jig to but you can get use to sharpening a full flat bevel. You will get plenty of different schools of thought on any sharpening thread. Good luck sorting it out.
Jim

[Tom M King]

The main reason I try to avoid grinding is the mess it makes in the old museum houses I work in, and there is always a lot of bare wood around, including the floors.

[Robert Hazelwood]

To answer the OPs question, you can do it either way. A lot of people like to sharpen on the hollow to get 2 points (lines, really) of contact with the stone. In that case you'd set your grinder guide for the final sharpening angle. But you can also grind a shallower bevel and then raise up when honing to get your final angle (secondary bevel). With the second approach you only have a single line of contact (the edge) so you are reliant on muscle memory and developing feel in order to maintain the angle. In exchange, you reduce the amount of material to be honed and you can get more honings between grinding sessions. Sharpening pure freehand sounds like an amazing feat when described but it's really not that hard, and its necessary for some tools (like most knives).

[Jack Dover]

Have 2 sets of those Aldi's chisels....all are at 25 degrees....and haven't seen any "folding" yet.....what am I doing wrong?

No idea. Want me to fold them over for you?

[steven c newman]

I doubt if you can.....I tend to treat my chisels a little better than that...

[Rafael Herrera]

Have 2 sets of those Aldi's chisels....all are at 25 degrees....and haven't seen any "folding" yet.....what am I doing wrong?

I have set of the Harbor Freight chisels, they don't fold either.

[Charles Guest]

A ton of 01 tool steel sells for about $650. A woodworking chisel can be inexpensive, and still be of decent quality.

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A2 in various formats:

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