Honing after hollow grinding

[Jon Snider]

After reading posts from about 600 of the previous Neader pages (skimmed them over several months) I’m still confused about what happens when honing a chisel or plane blade after hollow grinding, be it free hand or with a jig.

Does one just hold the hollowed metal flush to the honing stone and create a “microbevel”, albeit one exactly parallel to the original two edges of the metal as it came off the grinder, say at 25 or 30 degrees? Or do you change the angle and form a secondary angle on the already fairly small metal cutting edge?

It seems sort of intuitive to me that if one of the reasons for using microbevels is to decrease the amount of metal being sharpened, and speeding up and easing the amount of work, this has already pretty much occurred after the hollow grinding.

For purposes of discussion I’m using an 8” CBN wheel.

Thanks, Jon

[Kevin Jenness]

Stop reading and get to sharpening and your confusion will be relieved. The easiest and most consistent way (without a jig) is to register the tool on the stone using the toe and heel of the hollow. You will be removing more material than if you raise the heel and make a microbevel. Some people raise the heel but then you have to rely on "feel" and practice to get the microbevel angle consistent. Try it both ways and see what works. You may find using a honing jig to achieve a microbevel works best for you.

[Jon Snider]

Kevin, thanks. Just to be clear I’ve been honing for a long time, mainly freehand but also have a drawer full of jigs. The CBN wheel is a new gift. Before that I could never get happy with the various white and blue ones on my old Baldor and never used them.

[Derek Cohen]

Hi Jon

I freehand on the hollow, which jigs the blade, maintains the bevel angle, and keeps the face coplanar.

Regards from Perth

Derek

[Jon Snider]

Thanks Derek. Was hoping you were up and about over there!

[Luke Dupont]

The really great thing about convex grinds is that you don't really need a micro-bevel.

I don't have a grinder, so I don't typically sharpen hollow ground tools, but if I did, I'd do as Derek describes and just sharpen them flat on the stone. I have sharpened many tools that came to me with a hollow grind, however, and I certainly did appreciate it.

Then again, I usually just sharpen with a full flat or slightly convex bevel on all of my tools, which aren't typically hollow ground. I just find it easier, as you don't have to worry about what angle your micro bevel is or go through the ordeal of grinding it back down when it gets too large. Easier to just be consistent for me.

Some people will use a small microbevel -- a truly micro bevel, on a hollow grind, though. I recall watching a video of David W. sharpening a plane iron on a Washita and a Transluscent, and advocating putting a truly small microbevel (like one or two strokes) on the edge with the transluscent -- small enough that it comes out quickly with the next sharpening just on the Washita. This would be a good way of doing it if you want a micro bevel. But I definitely wouldn't have a large micro bevel on a hollow grind, as that would create problems and soon change the cutting angle, I imagine..

[Derek Cohen]

Just for clarity, I differentiate between a micro bevel and a secondary bevel. This is not the way these terms are used generally, but I find the common way to cause confusion.

When I refer to a micro bevel, I mean a bevel that is very tiny … micro in size. Numbers? 1mm in width, or less. There is no angle implied by “micro bevel” - it may be coplanar with the bevel face.

A secondary bevel (and a tertiary bevel) is a bevel which is at a steeper angle to the primary bevel. A secondary bevel may be created by hand. It is almost always what is created by a honing guide. There is no size to a secondary bevel, just that it is higher than the primary bevel.

Now you can have a micro secondary bevel, and this is what may create in honing an edge when they list the blade for a few strokes at the end (see Rob Cosman and David Weaver).

When honing directly on the face of a hollow grind, as long as the hollow reaches the edge of the bevel, you will create a micro bevel (see my earlier photos). This is not a secondary bevel as it is coplanar.

A little to take in, hopefully not confusing, but I find it makes more sense.

Regards from Perth

Derek

[Keegan Shields]

Great description Derek. As I was taught in the Marine Corps: “Words mean things”

[Luke Dupont]

Just for clarity, I differentiate between a micro bevel and a secondary bevel. This is not the way these terms are used generally, but I find the common way to cause confusion.

When I refer to a micro bevel, I mean a bevel that is very tiny … micro in size. Numbers? 1mm in width, or less. There is no angle implied by “micro bevel” - it may be coplanar with the bevel face.

A secondary bevel (and a tertiary bevel) is a bevel which is at a steeper angle to the primary bevel. A secondary bevel may be created by hand. It is almost always what is created by a honing guide. There is no size to a secondary bevel, just that it is higher than the primary bevel.

Now you can have a micro secondary bevel, and this is what may create in honing an edge when they list the blade for a few strokes at the end (see Rob Cosman and David Weaver).

When honing directly on the face of a hollow grind, as long as the hollow reaches the edge of the bevel, you will create a micro bevel (see my earlier photos). This is not a secondary bevel as it is coplanar.

A little to take in, hopefully not confusing, but I find it makes more sense.

Regards from Perth

Derek

Good distinction! I was calling them both "micro-bevels" but I guess the term "micro-bevel" is there specifically to differentiate it from a "secondary bevel."

[Derek Cohen]

The really great thing about convex grinds is that you don't really need a micro-bevel.

I don't have a grinder, so I don't typically sharpen hollow ground tools, but if I did, I'd do as Derek describes and just sharpen them flat on the stone. I have sharpened many tools that came to me with a hollow grind, however, and I certainly did appreciate it.

Then again, I usually just sharpen with a full flat or slightly convex bevel on all of my tools, which aren't typically hollow ground. I just find it easier, as you don't have to worry about what angle your micro bevel is or go through the ordeal of grinding it back down when it gets too large. Easier to just be consistent for me.

Some people will use a small microbevel -- a truly micro bevel, on a hollow grind, though. I recall watching a video of David W. sharpening a plane iron on a Washita and a Transluscent, and advocating putting a truly small microbevel (like one or two strokes) on the edge with the transluscent -- small enough that it comes out quickly with the next sharpening just on the Washita. This would be a good way of doing it if you want a micro bevel. But I definitely wouldn't have a large micro bevel on a hollow grind, as that would create problems and soon change the cutting angle, I imagine..


Luke, I understand why you hone a rounded bevel. I am not convinced, however, that it is especially efficient. My Japanese chisels are all honed on the flat. No micro secondary bevel. This is made easier by the laminated construction, however many others (for example Warren) hone their solid blades on the flat.

The rounded bevel method has been popularised by Paul Sellers. I think that he advocates this as it does not rely on a grinder, and may be done freehand. It is a useful method to have under your belt - knowing many methods adds to your arsenal - and, indeed, I use it for Western mortice chisels (which use a 25 degree primary bevel - my Japanese mortise chisels are flat-honed at 32 degrees).

A question came up on another forum very recently about PS' methodology. This is what I wrote ...

I find it revealing that Paul Sellers uses 300/600/1000 grit diamond stones. This suggests that his sharpening method is inefficient. By contrast, many (myself included) begin their sharpening sequence from 1000 grit. Paul does not end with 1000 grit, and neither does anyone else, but this is not relevant here.

The reason he begins with 300 grit is because he has to remove more steel. The long, curved bevel face has far more steel to remove than honing a micro bevel (in the case of freehanding on the face if a hollow grind). or honing a secondary micro bevel (in the case of a honing guide). In the method I prefer - honing on a hollow - the amount of steel to remove is minuscule, and it is possible to even forgo the 1000 grit.

Regards from Perth

Derek

[Luke Dupont]

Luke, I understand why you hone a rounded bevel. I am not convinced, however, that it is especially efficient. My Japanese chisels are all honed on the flat. No micro secondary bevel. This is made easier by the laminated construction, however many others (for example Warren) hone their solid blades on the flat.

The rounded bevel method has been popularised by Paul Sellers. I think that he advocates this as it does not rely on a grinder, and may be done freehand. It is a useful method to have under your belt - knowing many methods adds to your arsenal - and, indeed, I use it for Western mortice chisels (which use a 25 degree primary bevel - my Japanese mortise chisels are flat-honed at 32 degrees).

A question came up on another forum very recently about PS' methodology. This is what I wrote ...

I find it revealing that Paul Sellers uses 300/600/1000 grit diamond stones. This suggests that his sharpening method is inefficient. By contrast, many (myself included) begin their sharpening sequence from 1000 grit. Paul does not end with 1000 grit, and neither does anyone else, but this is not relevant here.

The reason he begins with 300 grit is because he has to remove more steel. The long, curved bevel face has far more steel to remove than honing a micro bevel (in the case of freehanding on the face if a hollow grind). or honing a secondary micro bevel (in the case of a honing guide). In the method I prefer - honing on a hollow - the amount of steel to remove is minuscule, and it is possible to even forgo the 1000 grit.

Regards from Perth

Derek

Paul Seller's method is good for thin plane irons if sharpening free hand. I don't care to try to keep a 1/8" iron perfectly flat on the stone with such a registration surface, nor does it matter!
Another advantage is that it does allow a better cutting action on certain natural stones, particularly Arks, as less of the bevel is in contact with the stone at any one time. A large surface area on an Ark can often lead to the bevel "sliding on" the stone and a reduced cutting action. This is probably for similar reasons that short strokes, and small circular strokes are advantageous on Arks, as opposed to the typical continuous, full strokes that most people employ.

I don't really use Paul Seller's method as he shows, though. The curvature is barely noticeable on my tools by comparison. It's maybe 1-2 degrees of variation, if that. I do that in part to avoid "stiction", which I discuss below with regard to Japanese tools.
My method is far from the most efficient, I'm sure, but I rarely go any finer than a Soft Arkansas or Washita unless a blade is damaged or really worn down.

For Japanese tools, I keep an almost perfectly flat bevel, but I allow an imperceptible amount of rounding to occur at the top to avoid "stiction", as it's a real drag when your perfectly flat plane iron bevel suddenly sticks to the stone just as you're pushing forward, causing you to nose dive into the stone and create a micro/"macro" bevel that you then have to take out again, only to keep having the same frustrating experience occur. Not many people seem to talk about this, but it happens every single time I make the bevel perfectly flat. So, I can only guess that most people allow a tiny amount of rounding to occur, otherwise they'd almost certainly stumble into the same problem unless skewing the blade at a pretty significant angle.

But for Western chisels, or thick Western plane irons, I'd love to try the hollow ground approach one day. I can definitely see how it would make the sharpening process extremely efficient. I just can't justify owning a grinder currently. One day, when I have more space, and money!

I think Paul Sellers does a lot of what he does because it's accessible, and beginner friendly. Not everyone can own a grinder. And for beginners, it's far easier to return often to a coarse stone to remove chips and fix geometry (which, if you're not good at sharpening yet, you will mess up quite a bit). I speak from experience on the latter point, as when I was a beginner, I started with a #1000 grit waterstone, which turned out to be much too fine to address the work that needed to be done on factory ground tools. Of course, I didn't know that at the time, and wondered why my tool just never got sharp no matter how much I ground. It just wasn't coarse enough to get down to the edge. Then you start lifting up to get to the edge, and go a little too far. And then you *really* need a coarse stone or a grinder. Better to just start beginners off with the coarsest, flattest stone available, hence Paul's Diamond stone set up, I think.

[Andrew Pitonyak]

I use a hollow grind because:



It is what I own to sharpen; I own a Tormek so it will leave a hollow grind.
I have fast success because I simply register the "hollow" and go.


The hard work is done creating the hollow. After that, I can use a much higher stone. I usually start around 5K or 6K on the back then the hollow. I then jump directly to my 16K and do the same.

I do not use a guide at this point; it is easier to register against the hollow for me.

[Charles Guest]

You can hone on the grind for straight/very close to straight cutters, but it's easier IMO to do a little tip up on profiled cutters like your jack plane in order to maintain the shape at the end. I don't doubt that others have mastered doing so by honing on the grind though.

If you tip up over the grinding angle then your bench grinder can stay set at one angle, and any little adjustments you want to do to a particular cutter, with regard to angle, is done at the honing stone by tipping a little more or a little less, or perhaps none for a bench chisel for instance.

25* grinder (or even a little less) - change the ultimate angle at the honing stone.

[Bruce Mack]

I'm late to this but will add that hollow grinding allows easy side sharpening and honing of plane irons. Side sharpening is my preferred method as there is no loss of reference.

[Richard Hutchings]

I'm late to this but will add that hollow grinding allows easy side sharpening and honing of plane irons. Side sharpening is my preferred method as there is no loss of reference.

Are you referring to sharpening with the blade 90 degrees to the stone and moving the blade side to side? I like that method as well for plane blades.

[Bruce Mack]

Are you referring to sharpening with the blade 90 degrees to the stone and moving the blade side to side? I like that method as well for plane blades.
Yes I am. I feel I'm getting the best registration this way.

[Jack Dover]

When I refer to a micro bevel, I mean a bevel that is very tiny … micro in size. Numbers? 1mm in width, or less.
Derek

I'm sorry, but this is actually a milli-bevel. A true micro-bevel could be created on a strop or a felt wheel, the bevel created this way is within 1-3µm and it works wonders.

[Kevin Jenness]

"When I use a word," Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean- neither more nor less."

[Jack Dover]

The rounded bevel method has been popularized by Paul Sellers.

Sorry again, but Paul Sellers doesn't advocate for a rounded bevel, at least not in a sense his audience understands it. He has made at least two posts explaining the confusion. Please also note I'm neither his fan nor an advocate, quite the opposite.

He is actually reducing a heel. Not sure why, he seems to find some benefit in it (easier hollowing or something). That's the part that is rounded, you can see from the photos he used to post profusely, that his bevels never have a bulge in the middle like his fans do. Instead you will notice that the first half goes up pretty much straight and only then curves down fairly gently. He made a point on several occasions that one should never raise a handle higher than the primary grind angle while sharpening. I believe this makes his method a regular full bevel with this one quirk. It's just people are being people and don't listen to words (which are supposed to mean things).


I find it revealing that Paul Sellers uses 300/600/1000 grit diamond stones. This suggests that his sharpening method is inefficient. By contrast, many (myself included) begin their sharpening sequence from 1000 grit.


Are you sure you're not mixing up two different grit scales? ANSI 1000 grit produces a dull mirror finish and it would take you ages to get a burr on a full bevel. A JIS 1000 waterstone is way more aggressive. Also, Paul claims he's using his diamond plates literally for decades, if that's the case they're probably worn to 400-600 ANSI at this point.


The reason he begins with 300 grit is because he has to remove more steel.

Again, this is not accurate. His full sharpening protocol starts with 80 grits, an AlO sanding belt on a surface plate. 300 is the starting grit to freshen up a bevel that just started to get dull. I myself also don't do the full progression on a chisel that doesn't have lots of damage.

I personally think that convex bevel the way most people do it (to stress again, it's not how Paul Sellers does it) has one major downside: eventually the primary angle will get ridiculously high and the bulge right in the middle will turn manual regrinding into a true stoic spiritual practice. It's not a big deal if you don't mind a quick trip to a grinder, but this very crowd rejects grinders because, apparently, it's not "workmanlike" and "manly". A large portion of this crowd will also eventually complain about their tools not cutting clean, but that's a whole different story.

[Jack Dover]

The only important thing here is whether you get a highly polished cutting edge or not. You might think you do, but chances are you don't. At least this is the primary issue for friends and buddies reaching out to me for help with sharpening.

In my opinion this happens because we're doing it blind, essentially. All the sources say "do it like this, then go try cutting something, return to sharpening if it's not sharp". Basically the trial and error method, doesn't work very well for lone autodidact hobbyists, it just takes too long to figure. Microbevels, convex bevels, excentric jig wheels, etc - it's all to make sure the very end is properly ground, sharpened and polished.

What I personally found useful is a regular x40 jeweler loupe. Get one with a LED and a handle, folding types aren't very convenient to hold. This loupe allows seeing whether all scratches were polished out, any chipping or divots, even remnants of a burr are visible. Eventually you won't be using it that often, maybe every once in a while on a new chisel or a new stone.

Everything else in my opinion is a matter of a personal preference, like, I don't know what my preference would be today if I have had access to Tormek with a CBN wheel when I was just starting. As long as you're getting clean, shiny, oily looking surfaces from a chisel or a plane - you're good, the shape of the bevel or an edge doesn't matter. I buy lots of second hand tools, actually, only a handful of my tools were purchased new. There were all kinds of bevels, even on tools coming from highly accomplished workers - patternmakers, locally renown cabinetmakers, etc., so many things were "wrong" by today's internet opinion, yet it didn't prevent those guys from turning up first class work.

[steven c newman]

Sorry....I do not hollow grind. I go for a single flat bevel....K.I.S.S. Then right back to work....


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

[Kevin Adams]

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

Funny how it kinda sneaks up on you, doesn’t it?? Haha!

[Maurice Mcmurry]

I have not read this whole thread... When I have access to a wheel I always hollow grind. I follow up with a strop, a stone, carborundum, or fine sandpaper. When the hollow disappears it is time to re-grind. When I am at work and in a pinch I have found that a brick and some spit will renew an edge. If the tool is hollow ground sharpness happens a lot faster.

[Luke Dupont]

Sorry again, but Paul Sellers doesn't advocate for a rounded bevel, at least not in a sense his audience understands it. He has made at least two posts explaining the confusion. Please also note I'm neither his fan nor an advocate, quite the opposite.

He is actually reducing a heel. Not sure why, he seems to find some benefit in it (easier hollowing or something). That's the part that is rounded, you can see from the photos he used to post profusely, that his bevels never have a bulge in the middle like his fans do. Instead you will notice that the first half goes up pretty much straight and only then curves down fairly gently. He made a point on several occasions that one should never raise a handle higher than the primary grind angle while sharpening. I believe this makes his method a regular full bevel with this one quirk. It's just people are being people and don't listen to words (which are supposed to mean things).

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.

This relief on the back actually makes it easier to sharpen and meets with less resistance in the cut, as the heel is out of the way in both instances. A tool with this sort of bevel will cut deeper than a flat grind with any given stroke. It will initially meet more resistance than a hollow grind, but less resistance in very deep cuts, and has the advantage of being somewhat more robust than a hollow grind (hence excellent for axes, and mortise chisels I'm sure).

Relieving the heel also solves the "stiction" problem that I mentioned before, which occurs between two perfectly flat surfaces suspended in water or oil as when sharpening, and plagues me any time I have a truly perfectly flat bevel.

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.

[Warren Mickley]

478256

Looks like a high angle to me.

[Edward Weber]

Sorry....I do not hollow grind. I go for a single flat bevel....K.I.S.S. Then right back to work....


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


+1

I personally find the whole subject has become quite pretentious. Seems like no matter what you do, you're doing it wrong somehow in someones view, whether it does the job or not.

[Richard Hutchings]

+1

I personally find the whole subject has become quite pretentious. Seems like no matter what you do, you're doing it wrong somehow in someones view, whether it does the job or not.

What else do we have to talk about?

[steven c newman]

Maybe go off on a wild thread about "The Perfect Dovetail".......seems everyone has their own view on that.....

[Jack Dover]

Looks like a high angle to me.

Of course it's high, Paul seems to prefer chisels made from Play-Doh: Aldi and Sorby's that are notorious for being under-hardened, etc. He also seems to re-sharpen every 10 mins or so.

But look where a bevel transitions from flat to rounded. The widest chisel on the right is flat all the way up to 2/3 of the bevel and rounding begins right where the glare is. Same with the leftmost chisel. These actually match Paul's explanations - I could even pull a quote from one of his books. The middle one is actually badly rounded, lol. Seems to be the case of "do what I say, not as I say", happens to the best of us, I guess.

[Richard Hutchings]

Maybe go off on a wild thread about "The Perfect Dovetail".......seems everyone has their own view on that.....
You start it :-)

[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.

Tool Steel H13 Price, 2022 Tool Steel H13 Price Manufacturers & Suppliers | Made-in-China.com (https://www.made-in-china.com/products-search/hot-china-products/Tool_Steel_H13_Price.html#:~:text=ASTM%20A681%20AI SI%20D2%20H13%20P20%20A2%20O1,US%24%20600-650%20%2F%20Ton%20Min.%20Order%3A%201%20Ton)

A2 in various formats:

Tool Steel A2 Price, 2022 Tool Steel A2 Price Manufacturers & Suppliers | Made-in-China.com (https://www.made-in-china.com/products-search/hot-china-products/Tool_Steel_A2_Price.html#:~:text=Hot%20Work%20S2%2 F%20A2%20%2FD2alloy%20Tool%20Steel%20Price,%24%204 00-1500%20%2F%20Ton%20Min.%20Order%3A%201%20Ton)