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View Full Version : Sharpening removes too much metal?



Daniel Rode
08-06-2014, 4:34 PM
I've read a few replies that seem to indicate that sharpening with <insert method> will remove more metal from the chisel or iron. The idea being that over time the iron would become consumer faster with one versus another.

For example, working the entire bevel each time for a convex bevel edge or a flat single edge would remove more metal versus a primary/secondary sharpening.

Assuming that the angles are kept constant I cannot fathom how a dual bevel sharpening removes any less metal over over time. For convex bevel and single edges, the same amount of metal is removed each time. So the iron's life (length) would be shortened by a fixed amount each time. The dual bevel method would need to remove exactly the same amount of material off the length but the primary bevel would only move every few sharpenings when it's re-ground to reduce the width of the micro bevel.

If any method prematurely shortens the life of an iron, it would be the tri-bevel method. The reason being that with every re-sharpening the tertiary bevel is removed entirely and then re-formed. Even so, over many years the difference is probably trivial. In fact, so little metal is removed with each sharpening that they are all trivial. It takes many, many years of constant work to use up a chisel or a plane iron.

Now wear and tear on sharpening stones is another matter, entirely. The fine stones are going to wear much faster with a convex of single bevel.

Am I wrong?

Judson Green
08-06-2014, 4:38 PM
I don't get it either, It would seem to me that all methods would equally remove about the same amount of metal.

Bill White
08-06-2014, 4:50 PM
I get numb with all the blah, blah about sharpening. Tools which need to be sharpened will eventually wear. So what?
Ya wanna save tool steel or work with sharp tooling?
I can't EVEN imagine a blahlala stone that will allow me to split microns, cells, etc.
Get 'em as sharp as ya need and go to work.
I don't think that the guys who made some of the antiques in our home worried about a bunch of foolishness.
Sorry if I sound crass, but that's the way I work.
Bill

David Weaver
08-06-2014, 4:51 PM
None of the methods remove metal any faster than any of the other methods if all you do is remove the wear plus a narrow margin for security so you don't have to sharpen a second time.

A method that leaves a chisel or iron failing from wear only (and not chipping) will be easier on an edge.

The three bevel method doesn't consume any more than any other method since you're removing the wear with the secondary angle (and not the primary) and the tertiary bevel is only a slight bias to polish the second with only a few strokes.

Some of the comments about preserving irons come from people like me who get infatuated with some irons that are several hundred years old, and we want to remove the wear plus as little as possible after that. If you get a modern iron, or modern chisels, you can go willy nilly with them because there's nothing you can't just buy more of.

David Weaver
08-06-2014, 4:55 PM
I don't think that the guys who made some of the antiques in our home worried about a bunch of foolishness.
Sorry if I sound crass, but that's the way I work.
Bill

I would imagine that the guys who did the fine work (especially the trade carvers) were well versed in the various stones (and polishing compounds) and what it would take for them to get very sharp tools.

But for most of what we do, I agree. Sharpening discussions satisfy curiosity and not need. There are plenty of people who don't have any experience, though, and thus the talk about sharpening.

Matthew N. Masail
08-06-2014, 5:01 PM
I have a friend who builds beautiful Classical guitars, he just finished one in highly figured birds-eye maple, which is my favorite to play so far. he has a single king 800\4000 combo stone, and dosen't know what angle his plane iron are at. he does really fine work.

Zach Dillinger
08-06-2014, 5:01 PM
I would imagine that the guys who did the fine work (especially the trade carvers) were well versed in the various stones (and polishing compounds) and what it would take for them to get very sharp tools.
.

No doubt. And I would speculate that what they knew about getting sharp tools was taught to them by the person who taught them the trade, i.e. "you will use this stone in this manner at this time to sharpen tools while you work for me". They weren't bombarded by 74 different systems, techniques, and teachers.

Daniel Rode
08-06-2014, 5:04 PM
An artist might want to discuss composition and light with Michelangelo but he may want to discuss making brushes and grinding pigment. Both were important to him.


I get numb with all the blah, blah about sharpening. Tools which need to be sharpened will eventually wear. So what?
Ya wanna save tool steel or work with sharp tooling?
I can't EVEN imagine a blahlala stone that will allow me to split microns, cells, etc.
Get 'em as sharp as ya need and go to work.
I don't think that the guys who made some of the antiques in our home worried about a bunch of foolishness.
Sorry if I sound crass, but that's the way I work.
Bill

David Weaver
08-06-2014, 5:05 PM
No doubt. And I would speculate that what they knew about getting sharp tools was taught to them by the person who taught them the trade, i.e. "you will use this stone in this manner at this time to sharpen tools while you work for me". They weren't bombarded by 74 different systems, techniques, and teachers.

I wonder who brought their wares to them in those days. Some guy in a wagon? because there was no shortage of material describing the virtues of the different polishing compounds, stones, etc.

Presume that the apprentice used the masters stones, and if he wanted to do something different, TS, it would mean trying to figure out what you'd to do be able to eat.​

Mike Brady
08-06-2014, 6:14 PM
Any method preceded by a wheel grinder is going to remove more metal than stone lapping alone. I personally would not use a grinding wheel on anything but a coarse tool such as an axe. Certainly not on a plane or chisel. I also dislike concave bevels.

Malcolm Schweizer
08-06-2014, 6:37 PM
My name is Malcolm Schweizer, and I am a sharpaholic. I stay up late reading about bevel edges, microns, and honing jigs. I watch videos about sharpening. I look at sharpened edges under magnification. My family has suffered because of my addiction. My friends are slowly leaving me because all I do is talk about sharpening. We go to dinner at a friend's house and I ask if I can sharpen their knives, and then I'm talking microns, diamond paste, and stropping. It's a sickness. I tried rehab. They took all my stones away and forced me to work with dull tools. I didn't last. I had to run out and get a set of Shaptons. Now I am on the streets again, begging for things to sharpen.

Forgive the humor, but seriously- Sharpening for me is a hobby (crazy as it may sound), so I enjoy talking about sharpening methods. It all started as a kid- my uncle from Switzerland would bring us Swiss Army knives, and my grandfather (an amazing woodworker) showed us how to properly sharpen, thus starting a competition with my brothers to see who could sharpen the best. I do, however, think we sometimes get on tangents talking about sharpening and perhaps scare away people who don't understand why. A good reality check is welcome. In the end if you can get an edge fine enough to leave a good finish without tear-out, then you're OK- whatever method you choose. As you grow your skill, your definition of "good finish" gets more refined. Who was it that posted the image recently of the amazing fine finish on a piece of planed wood? Sorry that I can't give proper credit, but you could look at that image and appreciate what a well-honed edge can do for a piece. Now that I have reached a much higher level in my work, I pay a lot more attention to sharpening my tools.

My name is Malcolm Schweizer, and I am a sharpaholic.

Jerry Thompson
08-06-2014, 7:02 PM
I have all but trying all of the methods posted, ad nauseaum, I just grab a stone or two depending on what I need to do and have at it free hand. I get whisper shavings if needed or thicker ones when preparing a thicker board. I used to anguish over getting it all just as a post had described. If it works it works is the bottom line.

ian maybury
08-06-2014, 7:03 PM
I guess the presumption is that grinding (because it rapidly shifts material) is going to tend to remove more material than is absolutely necessary - while honing on a stone only removes what's needed to get an edge. Hence the rationale that re-grinding the primary bevels as in infrequently as possible/restoring the edge by honing as often as possible between grindings saves wearing the tool out too quickly.

My background is engineering, and hence my response is predictable Bill - and my apologies if the sharpening theads bore the tail off those of you doing it for years. I have to say though that i find it hugely useful to hear people discuss sharpening in technical/analytic terms. It means I can without anybody local to teach me (the skills are rare here) figure out what we're trying to achieve, and with relatively little trial and error make it happen. I likewise try to make a point of reporting my experience - on the basis that there are probably lots where I was.

It doesn't have to be done that way - an experienced tradesman using methods that work can simply pass on what he does - but the problem with that is that there's a tendency for a lot of hocus pocus/magic/rote thinking to creep in. The old you have to do this, this, this and this, and then rub it with the hair of a tomcat type stuff.

It's a very fundamental principle in industry - that it helps to explicitly de-mystify, explain and define processes in technical/numbers/systems terms. The problem is that if this is not done a mythology tends to grow up around certain jobs, and those with the skills tend to not share the information to strengthen their own position. Plus when the process is not quantitatively specified troubleshooting and improvement is much more difficult and less reliable - because it's not possible to measure and check out the variables to determine whether its properly set up or not.

It can go the other way of course - that people end up paralysed by or are unable to handle the resulting complexity...

Japanese waterstones are a case in point. I'm blown away by the way they make achieving incredible edges so easy, but if it wasn't for the likes of David Charlesworth pontificating away in the magazines about ten years ago about how he did it (and he's taken flak for being too technical) I'd simply never have known the possibility existed. :) The guy with the wagon around here when I was growing up only ever had ropy old carborundum stones and oilstones - and very few really knew how to get the best out of even them. Likewise on set up of hand tools....

ray hampton
08-06-2014, 7:36 PM
Any method preceded by a wheel grinder is going to remove more metal than stone lapping alone. I personally would not use a grinding wheel on anything but a coarse tool such as an axe. Certainly not on a plane or chisel. I also dislike concave bevels.

if you use a axe from dawn to dusk , you will not use a grinding wheel unless you got a slave to pack it into the forest, a file weigh much less

Derek Cohen
08-06-2014, 8:46 PM
Any method preceded by a wheel grinder is going to remove more metal than stone lapping alone. I personally would not use a grinding wheel on anything but a coarse tool such as an axe. Certainly not on a plane or chisel. I also dislike concave bevels.

I think that this misconception is at the heart of the OPs original post.

A grinding wheel removes steel from the centre of the bevel face to create a hollow. A high speed grinder does not reach the end of the bevel and, therefore, does not remove any steel from the length of a blade. A Tormek may or may not grind to the edge. In the case where it does grind to the edge, the fine wire created is about the same as raising a wire edge with a coarse waterstone.

The grinding method that will remove length is where one works on the flat face, either with a belt sander or coarse stone, and then adds a secondary bevel. In any even, it is not grinding, per se, that creates the most wear - it is grinding that goes past a fine wire edge.

Even then, wear is measured in microns and will take many, many years to create an appreciable reduction in blade length.

I'd rather have sharp blades, so do not worry about the length. Consider modern blades to be consumables.

Regards from Perth

Derek

Jim Matthews
08-06-2014, 9:08 PM
Isn't the thickness of the raised burr roughly the amount of metal removed by honing?

You can see swarf on most stones, and that's barely enough to discolor the lubricant.
I'm more likely to lose a chisel or plane iron than grind it down to a nubbin.

******

I grind with a knife maker's belt sander, and hone by hand
because I've seen a stray spark ignite shavings and sawdust.

That scared the bejabbers out of me.

bridger berdel
08-06-2014, 9:16 PM
I have a few times run into people who do what I would call abusive sharpening. Grind to the edge (or past). Hone minimally or not at all. Use the tool with the necessary too much effort.

Some have been open to improving their sharpening skills, some not.

David Weaver
08-06-2014, 9:22 PM
Ditto to what derek said, proper hollow grinding doesn't remove more metal than anything else. The grinding should be left short of the edge, especially on a dry grinder, and I'll dry grind anything, even japanese chisels, and rehab candidate japanese irons - but that is rare and I never let them get hotter than what I can pull slowly across the palm of my hand (which is how I cool an iron to begin with).

Any method of grinding that comes just short of where the stone work is occurring should be a fairly sparing method.

Winton Applegate
08-07-2014, 1:08 AM
blahlala stone

Cool ! Is that pidgin Hawaiian I am hearing ?
Isn't it da kine stone ?

I'm all pau wid dat brah.

Hey, as I always say, "Good enough is good enough" (but better's better)".
:)

george wilson
08-07-2014, 9:42 AM
I doubt any of you guys will wear your chisels or plane irons down to the nubs in your life time. Besides,the old timers always said their tools got better after they were shortened some by repeated grindings and sharpenings.

In the words of old Mr. Simms,the original old English furniture conservator in the museum:" Shut up and get back to work"! :)

Mike Brady
08-07-2014, 10:41 AM
I wouldn't disagree with anything you say, Derek. The only qualifier is that you are assuming a high level of skill from the operator on the grinder. Grinding wheels (not Tormek) work very quickly and can ruin steel in an instant. If you watch the scissor-making video, a skilled individual can get beautiful results on a high speed wheel. My point is that using a grinder requires the right equipment and much experience. Lapping stones are at the other end of that scale of experience....about the worst you can do is get tired fingers.

Daniel Rode
08-07-2014, 11:16 AM
I don't know about the high level of skill to operate a grinder. I find the grinder to be very simple to use. I just bought one recently. I read a couple of articles and after 5 minutes I could do what I needed. Go slow and don't overheat the edges... easy as pie. A file is harder to use and grinding on stones or sandpaper take forever.


I wouldn't disagree with anything you say, Derek. The only qualifier is that you are assuming a high level of skill from the operator on the grinder. Grinding wheels (not Tormek) work very quickly and can ruin steel in an instant. If you watch the scissor-making video, a skilled individual can get beautiful results on a high speed wheel. My point is that using a grinder requires the right equipment and much experience. Lapping stones are at the other end of that scale of experience....about the worst you can do is get tired fingers.

David Weaver
08-07-2014, 11:20 AM
Side comment for people who have trouble grinding.

We often talk about how hard it is for an iron like M2 (HSS) or something on the stones, but the bigger pain to me is grinding. The thicker an iron gets, the longer the grind takes. The higher the alloy, the longer the grind takes. Beginners are probably going to have more luck grinding a stock stanley iron than they are an A2 iron 1/8th of an inch thick that has similar temper temperatures (and thus gets out of temper at the same high temperature on the wheels).

Something thin and a bit softer, like stock stanley, or even like one of the buck brothers irons at HD, will be easier to grind without overheating.

I'm sure a lot of beginners park their irons on the corners temporarily before they change direction, and even if they don't, if you think about it, those corners are going to spend more time on the wheel as you change directions and they don't have metal on one side to dissipate the heat - they'll be the first to burn. If that's an issue, just run the iron across the wheel one direction, take it out of the cut and do it again, like a typewriter.

And if you burn the very corner of an iron that you're cambering, anyway, don't worry about it when the part that's blue isn't going to be in the cut, anyway.

There was so much talk about burning irons on the forum that I never did burn an iron until I got a little bit more comfortable, but I've never seriously drawn the temper out of anything, and now on a maintenance grind never get the iron hotter than what I can drag across my palm to cool it, and I only do that to check the temperature of it so that I don't grab it to hone and burn my fingertips. water would never boil on any of the irons I've ground recently, except maybe HSS when you can be less restrictive about temperature. I think I could probably blue a mujingfang HSS iron and it wouldn't make any difference, but they *are* a pain to grind because they are a lot more resistant to the wheel's abrasion. What I'm getting at is that with all of the discussion beforehand, with a decent rest and a freshly dressed coarse grit wheel, most newbies aren't going to have much trouble with burning unless they literally stop moving the iron in the middle of a grind.

george wilson
08-07-2014, 11:42 AM
Blue makes no difference ion a HSS plane iron. They are TEMPERED red hot. That is TEMPERED,red hot,not HARDENED red hot. They are hardened white hot.

South Bend lathes,many years ago,published a picture of a HSS lathe tool being heated red hot with a welder's torch,while still cutting a deep cut in mild steel in a lathe. The title was "Red hot and still sharp".

I'll tell you how to lose tool length: I was using my 1" Marples chisel,from the set I bought in the 60's. I was using a mallet,but I WAS NOT abusing the chisel. Suddenly,1" broke off the end of my chisel. It was just TOO HARD!! Not enough mechanical strength when steel is too hard. I re ground it,and still use the set of chisels. That has a LONG time ago,and I used them throughout my career,on everything I made that needed chiseling. They have lost hardly any length(except for that 1" one:) )

Steve Voigt
08-07-2014, 12:02 PM
In the words of old Mr. Simms,the original old English furniture conservator in the museum:" Shut up and get back to work"! :)

The best advice I have read here in a long time. I think I will take it.

Winton Applegate
08-08-2014, 4:32 AM
Some one mentioned I sounded as if I were disparaging the Hawiian people or making a racist comment.
Anyone who knows me knows I disparage equally.
I was referring to the word
"Blahlah"
in the thread that said
a blahlala stone
http://www.urbandictionary.com/define.php?term=Blalah

To me that means big I actually understood it to mean fat.

I just wanted to know if Bill White was speaking a word the local Hawaiians use . . .
brah no Talk Stink

george wilson
08-08-2014, 8:53 AM
Winton,I have to say that it is my sense of humor that always gets me into trouble!!:) Often people do not get it.