Rolled Bevel vs Micro Bevel vs Hollow Grind

[David Barnett]

I would have to disagree with this presumption that surface speed allows you to remove more material faster. Remembering this thread is about sharpening tools, not pushing a piece of scrap steel into a grinding or cut off wheel as hard as you can. Even then you will find that you can't grind all that fast either…

The principles of grinding and abrasive removal of tool steels, edge and otherwise, having long been established, well-known, widely published and in constant industrial use would tend to refute your anecdotal and/or intuitive experience regarding rates of metal removal, Brian, and there is little to nothing new to learn or discover in this regard, although the practices you've adopted and with which you are apparently comfortable give you results adequate results, so I have no interest in dissuading you from them.

Might I suggest that your following statement may be indicative less of general principles than your individual performance of grinding?

I was quite surprised at the results when it was all done. Slow speed grinding allowed me to remove material on average 40% faster.

Whatever the case, I would disabuse others from adopting those conclusions before surveying the accumulated knowledge in the field and would suggest acquiring that broader perspective.

I'm sure there is a formula that will determine how many seconds you can keep a piece of steel pressed up against a grinding wheel, at a specific pressure, at a variety of speeds before it reaches 300 degrees… So if someone wanted to really get stuck into it they could determine the optimum speed…

For over a hundred years those factors have been known, published and routinely applied.


While feed rates and grinding speeds are intimately related, and while the range of effective usefulness is narrowed considerably insomuch as grinding a tempered tool to a sharp edge is a balancing act of maintaining that narrow thermal band through chosen abrasive, abrasive particle size, presentation characteristics such as friability, tribological characteristics such as coolants and lubricants, and the feed speed of target metal to surface speed of abrasive presentation and its resistance to slowing can be independently measured and controlled, any conclusion that lower grinding speeds remove metal more quickly than faster speeds is refuted by ultra-high speed grinding (UHSG) technology, while outside the purview of day-to-day home shop practice certainly illustrates the underlying fallacy of your assumption, an assumption for which I cannot find support from my admittedly casual and far from expert experience of the literature and in-place practice.

One current book, Grinding Technology: The Way Things Can Work: Theory and Applications of Machining with Abrasives by Stephen Malkin (Apr 15, 2008), covers the waterfront and unlike so many advanced books on the subject, is affordably priced for individuals without scholastic or industrial research and acquisitions budgets.

Of course, there is a staggering wealth of information online, as well, but I'm unprepared to offer a bibliography. This book, as I've said, gets most of what's happened and happening between two covers without bogging into machinist's tables of which abrasive at what speed for what material, and so on.

So while I'm dubious of those who would derive and assert grinding principles from everyday experience and personal practice of grinding and sharpening in the home workshop, if one finds their use of Tormaks and other wet grinders to speed things along by eliminating errors made using higher speed dry grinders, that's a pretty good tradeoff if one needs that.

For others with the understanding and technical skill to move beyond that, they'll likely appreciate commensurate gains in speed. As I'm comfortable and facile using both slow and high speeds I speak to this from actual experience. So again, like so many processes in the home woodshop, what's best is more a matter of preference and habit than a rigorous demonstration of industrial practice.

So if someone says "it's faster for me" — I'll accept that. If someone says "it's faster for me so this must be how it works" — not so much. Just sayin'.

[David Weaver]

Another good example of there probably being a difference between optimized professional comparisons and anecdotally driven conclusions. (sort of along the same lines as my suggestion in prior threads to avoid blogs and non-professionals for advice that needs to be precise.

Of course, I am an amateur, but I'd never suggest that someone should take any advice that I provide if they can get a professional opinion (thus no blog about sharpening stones or plane building or sharpening razors or any other such thing that entertains me).

[Winton Applegate]

if they can get a professional opinion

I have worked along side many "professionals" in several different trades :

• High end art bronze sculpture and architectural Foundry work
• High end luxury sports car mechanic and body work
• Getter done art steel sculpture from sconces to full size fancy steel canopy beds
• Bicycle frame building and high end bicycle mechanic work off and on from 1972 to present day
• Residential electrician/electrical work
• Metal machining including engine block and head rebuild work

There may be another one or two that don't come to mind but . . .
one common thread I have observed is . . .
almost to a man (and some women) they don't do what is in their best interest or is less expensive or less time consuming or produces the best product or is the latest techniques. What do they do ?
what ever the heck they tried that sort of gets them by and they don't have to think about much. it is like they reinvented the wheel because they are too proud to look to see how the best in the business are doing it. Or how the last hundred years have shook out.

Nearly always I study the heck out of what ever I get involved in including the trade magazines and books, most all of this was before the internet or at least me being on line.
Often being the new guy on the line I find I still have superior info and tools in the back of my mind but what do we use ? Just some sort of what ever good enough. Wasting time, products and not getting the best results.
Maybe it is the high altitude out here. I don't know. There have been exceptions and we have really got up on the wave but not often.
When people say something to me like "I am going to take it to a professional" or "he knows best; he's a professional" my first thought is
yah don't know do ya'?
and
that "professional" is often just some guy who was working at an espresso machine a month ago and is now trying to get by at this new gig working for an "owner" of the business who is a business person first and not too sure about the hands on details them selves.

I see it too often and that espresso guy when he gets off work . . . does he go home and study his craft so it goes better the next day, as I always did ? No he goes out and parties and when he shows up the next day has forgotten half of what I taught him the last week or so.
That sounds sooo negative as I type it but that has been my experience over the last thirty years and more.
People just don't DIG HARD for the edge they just laze along. Too many distractions to just focus on being a "_______". Fill in the blank.
I think often the amateur or the enthusiast may actually have something quite valuable to contribute because they have dug hard because they enjoy the learning and because they have the time to devote. Or a better way of putting it is . . . they have devoted the time.

[David Barnett]

Of course, I am an amateur, but I'd never suggest that someone should take any advice that I provide if they can get a professional opinion (thus no blog about sharpening stones or plane building or sharpening razors or any other such thing that entertains me).

Blogs certainly do have their raisons d'être, commercial or otherwise, don't they, and it's not uncommon to find craft blogs where one attempts to credentialize interests and accomplishments, often on a path to commercial ambitions—one reason I skeptically take most blogs as self-promoting or agenda-driven, or at the very least, narrow and highly idiosyncratic personalizations celebrating one's craft journey—all to the good as long as such limitations are kept in perspective.

Too commonly nowadays, at least to my thinking, to recognize or revere something beyond another's skill level or cultural ceiling readily invites invective and scorn, charges of snobbery and elitism, and this reactionary philistinism worsens should one criticize or even question one's apotheosized craft popularizer, mentor, hero, whatever.

I am amused that some mistake adequacy for mastery. I am also amused that the longer one persists at a practice, the more likely is one to regard that enduring repetition as proof of their practice's soundness or personal expertise. I am still further amused that many ducklings waddling behind a another duck can somehow confer accomplished status on that lead duck, no matter where it's been or where it's headed.

[Brian Ashton]

I started skimming a fairly drawn out response to my post that was peppered with a condescending tone and soon remembered that the point of this thread was sharpening a chisel and stopped reading… Do I really need to read volumes of carefully collected imperial evidence for grinding pretty much anything that exists to do such a task? Hardly. Do I want to study all the factors that affect grinding a infinite amount of materials, memorise the formulas, physics laws that make it possible and become a super grinding freak… I have better things to do with my time - like build nice furniture.

[Hilton Ralphs]

Do I really need to read volumes of carefully collected imperial evidence for grinding pretty much anything that exists to do such a task?

Nah, just empirical evidence.

[Brian Ashton]

Nah, just empirical evidence.

Shows you much i care about the term - can't even be bothered to spell it right.

[David Weaver]

Blogs certainly do have their raisons d'être, commercial or otherwise, don't they, and it's not uncommon to find craft blogs where one attempts to credentialize interests and accomplishments, often on a path to commercial ambitions—one reason I skeptically take most blogs as self-promoting or agenda-driven, or at the very least, narrow and highly idiosyncratic personalizations celebrating one's craft journey—all to the good as long as such limitations are kept in perspective.

Too commonly nowadays, at least to my thinking, to recognize or revere something beyond another's skill level or cultural ceiling readily invites invective and scorn, charges of snobbery and elitism, and this reactionary philistinism worsens should one criticize or even question one's apotheosized craft popularizer, mentor, hero, whatever.

I am amused that some mistake adequacy for mastery. I am also amused that the longer one persists at a practice, the more likely is one to regard that enduring repetition as proof of their practice's soundness or personal expertise. I am still further amused that many ducklings waddling behind a another duck can somehow confer accomplished status on that lead duck, no matter where it's been or where it's headed.

Unfortunately, it's not exclusive to woodworking, actually, I think it's inclusive to everything. My first taste of it was as a kid having a fascination with ag equipment (my relatives were farmers). There are far more people willing to write a book with glossy information and extreme numbers of errors in the technical details than there are folks who will get all of those details right (rest in peace, JR hobbs). I guess it's mostly a matter of what comes first. The desire to know and do, or the desire to write.

[Hilton Ralphs]

Shows you much i care about the term - can't even be bothered to spell it right.

No worries, you were only off by an inch.

[John Coloccia]

Do I really need to read volumes of carefully collected imperial evidence for grinding pretty much anything that exists to do such a task? Hardly. Do I want to study all the factors that affect grinding a infinite amount of materials, memorise the formulas, physics laws that make it possible and become a super grinding freak… I have better things to do with my time - like build nice furniture.

I somewhat agree with you, Brian. While I think it's interesting to share various ideas and techniques with each other, some of this stuff borders on a little looney because anyone can go out into their shop and simply try a technique to see if they like it. We can talk all the theory we want, but all that really matters is that you get the results you're looking for. In my former life as an engineer, I always got a little giggle when someone would come into the lab and say, "You're not doing this right", or "That's not how it's supposed to work". Ha ha ha...shut up, pay attention and come learn something, kid.

[bob blakeborough]

Personally I would not let it go, because like you said some beginner could find this thread, and take something as gospel without completely understanding the variables at play. Grinding is a lot like other machining operations, in that some situations are completely counter intuitive.

The other thing to keep in mind, is that some people are super touchy when something is presented that is different from what they do.

The rub is that most (not saying ALL) beginners are going to glaze over when discussions get overly technical. They are usually looking for something simple and easy to understand, and then after that is practiced and grasped, more subtle nuances can expanded upon and understood with greater interest. These conversations rarely appeal to the rank beginner, and in reality tend to overwhelm and intimidate rather than help (I am speaking as an almost beginner myself). It is not friendly feeling nor inviting. It can easily make one feel like there is no point in trying as unless you are an engineer you could never be a woodworker...

I know of no person who learned to throw splitters, sliders, change ups etc without first just having fun tossing a ball around with dad...

I am really not trying to say that there is no room for appreciating and learning from those who are masters, but that sometimes we (ie ME and some other relative newbs) are quite content to have things made clear and simple and look forward to learning more as we go rather than having every single technical aspect thrust down at us in what can feel like a condescending, patronizing manner (be it intended or not), so when you completely dismiss something as pure crap that we may have actually identified with and were able to easily process and utilize, it can be alienating. While some of you think you are doing this for the benefit of the rank beginner, you are really just comparing notes with other mid to heavily experienced folk...

It isn't always what you are saying as much as how you are all saying it...

[Steve Voigt]

The rub is that most (not saying ALL) beginners are going to glaze over when discussions get overly technical. They are usually looking for something simple and easy to understand, and then after that is practiced and grasped, more subtle nuances can expanded upon and understood with greater interest. These conversations rarely appeal to the rank beginner, and in reality tend to overwhelm and intimidate rather than help (I am speaking as an almost beginner myself). It is not friendly feeling nor inviting. It can easily make one feel like there is no point in trying as unless you are an engineer you could never be a woodworker...

I know of no person who learned to throw splitters, sliders, change ups etc without first just having fun tossing a ball around with dad...

I am really not trying to say that there is no room for appreciating and learning from those who are masters, but that sometimes we (ie ME and some other relative newbs) are quite content to have things made clear and simple and look forward to learning more as we go rather than having every single technical aspect thrust down at us in what can feel like a condescending, patronizing manner (be it intended or not), so when you completely dismiss something as pure crap that we may have actually identified with and were able to easily process and utilize, it can be alienating. While some of you think you are doing this for the benefit of the rank beginner, you are really just comparing notes with other mid to heavily experienced folk...

It isn't always what you are saying as much as how you are all saying it...

You should keep in mind that the forum doesn't exist solely to provide advice to beginners. People of all skill levels come here. While you may not like highly detailed, technical posts, I really enjoy them. I'm certainly no master, but I'm not a beginner, and generic beginner's advice is useless to me (especially when it's blatantly wrong).
But I don't have any objection to the type of posts you like; I just skip over them. You can do the same with the detailed, technical posts. There's something here for everyone.

[Jim Koepke]

Here's my Attachment 267275.

Though there is a love of technical information coursing through my veins, it seems superfluous to bring up high speed methods of removing steel in a discussion started to glean information on why folks might choose one method over another to produce an edge on their cutting tools.

There was even this in the original post:

PS This is part of a bigger question I asked about on another forum about shifting through the information provided by so many woodworking 'gurus'.

PSS Hopefully not too divisive a topic; that certainly is not what I'm looking for in asking - quite the opposite.

Sorry Tony, your hopes may be for naught.

So in an effort to get back to the original intent:

I like hollow ground edges but do not have the equipment in my shop, at this time, to produce a hollow grind. The reason for liking a hollow grind is the way it "clicks" on a stone when honing by hand.

So many blades have come my way that were messed up by someone with a grinder that it makes me think they have a learning curve a lot of people ignore. The lust for speed may be at play in this.

Micro bevels seem to work best when one is using a guide. My sharpening is mostly by hand and a micro bevel or a secondary bevel is difficult to repeat accurately. My thickest blade is often given a micro bevel just because it is difficult to sharpen it without doing so. After a few sharpenings it is usually returned to the power sharpening system to reestablish its bevel.

A rolled bevel (Paul Sellers method?) seems to work for some, but it isn't the way of choice for me. Isn't in reality just a series of micro bevels?

Also a lot of times my chisels are used bevel down in cutting dados. For this a low angle grind seems to work best for my liking. Not sure how the convex bevel would be on this kind of work.

My grandkids are currently visiting and my oldest grandson is working with me in the shop. One of my paring chisels comes the closest to having a convex bevel. It is sharpened at ~15º. I was showing my grandson the difference between a low angle, 15º and high angle, ~25-30º, chisel's ability to pare end grain. There are enough chisels in my shop that some are ground at low angles for paring and others a bit steeper for chopping.

My chisels are mostly flat ground due to the sharpening system purchased years ago, the Veritas MK II power sharpening system.

My goal is far away from trying to remove the most metal the quickest. It is more like removing just enough metal in a timely fashion.

Sometimes that means just a quick stropping every few cuts. Sometimes it means just a few swipes on the 8000 stone and back to work. If there is a nick, most of the time it can be taken out within a few minutes on a 1000 stone.

So my concern is not how many inches of steel can be ground away in seconds. My concern is to remove a thousandth or less of metal and getting back to work.

jtk

[David Weaver]

Backing away from who likes what in their posts or what real life doesn't turn out to be the same as experts says it does, David saw a post that said metal can be removed faster with slow speed than high speed, and didn't agree with it and had proof as to why. I think the back and forth that occurs trying to find a or the right answer is useful. It's something that's sometimes lacking on the forums because there is a slice of the posting population that does not like any disagreement of any kind to be had on open forums. To me, that's too bad. I'm not in that group.

I thought the comment about slow grinding being faster for heavy removal was puzzling and to go without David's reasoned response, even though it was in direct conflict with another statement, really doesn't do anyone any service.

[Jim Koepke]

I thought the comment about slow grinding being faster for heavy removal was puzzling and to go without David's reasoned response, even though it was in direct conflict with another statement, really doesn't do anyone any service.

There is also the vast differences in the different systems available.

A slow system with a water cooled wheel may have a speed advantage over a fast grinder without cooling or quenching. Unless one doesn't care about the outcome of the metal's temper.

A fast wheel with a cooling system may be faster at removing steel.

It may be possible to find 30 angels dancing on the head of a standard tailors pin. Yet a pin used commonly by map makers could comfortably support 40.

Maybe a consideration for what will most commonly be found in our shops or the supply houses we frequent should be one qualifier for what is included in such discussions.

jtk