Sharpening Question

[Justin Chen]

I've been reading Ron Hock's "The Perfect Edge" and had a question. After you flatten the back of a chisel/plane iron do you need to flatten everytime you sharpen or only every once in a while?

[Don Dorn]

Once is enough - you don't have to deal with it again as long as you got it flat. Now, the only thing to remember is that the back should never see any grit lower than your polishing stone. After you get a burr on your sharpening bevel, you simply remove it by taking that wire edge off on the polishing stone. It will only get better over time.

There will some that chime in and talk about the ruler trick, and while I'm not completely against it, I can only say that I've had much better luck now and get irons much sharper (will slice effortlessly though receipt paper) that I've done away with it. I invest the time up front and then freshening a blade takes just long enough to get a burr on the sharpneing bevel on the medium stone, then polish it a few strokes on the polishing stone. Turn it over and wipe the wire off on the polishing stone and you are done. Just an opinion, but I'm quite sure you'll hear others speak highly of the "ruler trick".

[Jim Koepke]

There is a place for everything as long as everything stays in its place.

The ruler trick is just a short cut. It does not finish the job at hand, it only delays it. I have used it and at times it is a good trick to know. It is also good to know exactly how it changes the dynamics of the blade on which it is being used.

When I sharpen a blade, I almost always give it a few swipes on the back to start out. This does a few things.

First, both sides of a sharp edge get some wear. On bench plane blades there is often some shmutz left where the chip breaker sits near the edge. A few swipes on the fine stone will remove this and make the area easier to see.

Next, on water stones this also raises a little slurry to help see that the blade bevel is set on the stone. The surface tension of the water will make the slurry climb up the back of the blade.

Then there is the fact that I am not as fastidious as some about getting a mirror on the back of all my blades. So the work on the back is just a continuation of making good enough just a bit better a little at a time. Some of the pits, scratches and hollows on the backs of blades have faded and disappeared over time through use and sharpening.

jim

[Larry Williams]

I've been reading Ron Hock's "The Perfect Edge" and had a question. After you flatten the back of a chisel/plane iron do you need to flatten everytime you sharpen or only every once in a while?

A plane iron will have wear on the flat face that needs to be removed at each sharpening. You'll even want to refresh the flat face of a chisel at each sharpening because, at the least, you need to remove the wire edge created when honing the bevel.

Every time you sharpen you need to hone both faces that make up the edge or you're not really getting the tool sharp.

The ruler trick is problematic in that it's not repeatable. If you've ever built something like a wheel chair ramp you'll begin to understand this. Say a 16 foot long ramp that rises only about 18". The very acute angle where the stringers meet the ground will change dramatically with very small variation in elevation at the other end. You're dealing with a much more acute angle with the ruler trick and even a slight difference in where the ruler is placed or how much of the tool hangs over the ruler will have a huge effect on the acute angle where the tool meets the stone. Your only options are to completely remove the flat created by previous use of the ruler trick or to increase the size of that flat. In the first instance, there's no benefit from the ruler trick and the in the second instance the ever growing flat becomes more of a problem than what the ruler trick was intended to deal with.

[Jim Koepke]

A plane iron will have wear on the flat face that needs to be removed at each sharpening. You'll even want to refresh the flat face of a chisel at each sharpening because, at the least, you need to remove the wire edge created when honing the bevel.

Every time you sharpen you need to hone both faces that make up the edge or you're not really getting the tool sharp.

The ruler trick is problematic in that it's not repeatable. If you've ever built something like a wheel chair ramp you'll begin to understand this. Say a 16 foot long ramp that rises only about 18". The very acute angle where the stringers meet the ground will change dramatically with very small variation in elevation at the other end. You're dealing with a much more acute angle with the ruler trick and even a slight difference in where the ruler is placed or how much of the tool hangs over the ruler will have a huge effect on the acute angle where the tool meets the stone. Your only options are to completely remove the flat created by previous use of the ruler trick or to increase the size of that flat. In the first instance, there's no benefit from the ruler trick and the in the second instance the ever growing flat becomes more of a problem than what the ruler trick was intended to deal with.


What he said!

Very well said Larry.

jim

[Adam Cherubini]

A plane iron will have wear on the flat face that needs to be removed at each sharpening.


The problem i have with this is the amount of metal that needs to be removed. Theoretically, a tiny wear bevel requires the removal of that depth across the entire back. I think one is better off working the smaller area of the bevel longer.

I used to sharpen the way Larry suggests and I got good edges, but it took me a while. I've seen Larry sharpen and it doesn't take him as long as it took me (and he doesn't use any exotic stones or anything). So I think this is a bit more complicated. He may be doing something, making judgements etc etc that isn't entirely clear in his post.

What I'm doing now is grinding my bevel away and honing up free hand. I hone the bevel until I get a wire edge (on a coarse stone), then I quickly remove that wire on my finest stone, working the back of the tool.

I switch to a fine stone for the bevel and work that until I raise a wire. This can be tough to do freehand. I think guys sometimes work their edge round (free hand) and subsequently polish a portion of the bevel just behind the edge. They hone and poilish and never get sharp. That's why its important to get a wire edge on your finest stones. I think this is easier to say than do.

After giving a couple lectures I now call my approach "results based". I think you need to see and feel what's going on and have some objective critieria to let you know where you are in the process. For this discussion, my recommendation is to mirror polish your backs flat. Then work the bevel until you can raise a wire edge on your finest stone.

I'm also an advocate of stropping which theoretically rounds your edges over. But I really like the edges I'm getting. Nobody complains that carving tools don't work well with rounded edges. One thing is certain, you need polished shiny surfaces at your edge. Anything less will be duller and will break down faster.

And I sharpen just about everything in my shop to this same standard, be it hewing hatchet or lathe tool. That's why I have a lock on my tool chest! People who aren't (hand tool) woodworkers or who are under the age of 18 have no business touching my tools. I've seen people cut themselves with my hand saws. If you get good at sharpening, please be careful. You don't have to make much of a mistake to cut yourself with a really sharp tool. I say that my chisels will move toward my hand and cut me thru gravitational forces alone. I generally won't allow them loose on my bench. They will come find me!

Adam

P.S. I've passed around my tools at some talks I've given. You can always spot the power tools guys in the crowd. They run their thumbs across my chisels' edges, nod, then look at their thumbs. The hand tool guys take their glasses off and hold my tools up to the light.

[John Stan]

This is helpful dialogue from folks with significant expertise. While you are here, I will chime in and say that I never seem to get a wire edge. I have used various honing jigs and Shapton stones from 1K to 16K, it just seems that no wire edge is appearing. What does this indicate? What is the secret to getting the elusive wire edge?

Thanks,
-John

[Nelson Howe]

Adam, I'm curious as to why you remove the coarse stone's wire edge on your finest stone before honing the bevel on the finer stone. Seems like most of the reommendations I encounter have you wait to wipe the wire edge until after you have honed the bevel on the finest stone. Does it matter?

Nelson

[Don Dorn]

In my opinion, make sure the back is completely flat. Then, when you run the sharpening bevel (usually 5 degrees or so more than the grind bevel), a few times on the medium stone, you should feel it on the back. Even A2 blades will give this indicator to you.

If you cant, try to use something that has a defined edge itself like the the edge of a retracted pen or edge of small knife to softly set against the edge at an angle. You should find it there at that point. Make sure you have a burr all the way across before going to the polishing stone.

I suspect you are trying to feel something akin to a scraper burr and it's not near that defined. Again, just my opinion and along with another $1, you can get a cup of coffee.

[Derek Cohen]

This is helpful dialogue from folks with significant expertise. While you are here, I will chime in and say that I never seem to get a wire edge. I have used various honing jigs and Shapton stones from 1K to 16K, it just seems that no wire edge is appearing. What does this indicate? What is the secret to getting the elusive wire edge?

Hi John

The simple answer is that you are not honing across the bevel face. You stop short before the face is honed enough to be flat across to the back of the blade.


Adam, I'm curious as to why you remove the coarse stone's wire edge on your finest stone before honing the bevel on the finer stone. Seems like most of the reommendations I encounter have you wait to wipe the wire edge until after you have honed the bevel on the finest stone. Does it matter? Nelson

Hi Nelson

This is a continuation of the previous reply (above).

I always remove the wire edge (on the finishing stone) before moving on. Keep in ming that I do most of my sharpening freehand, which makes this method easier, but I would do the same with a honing guide if there is sufficient room to run the back along a waterstone while the blade is in a honing guide.

The wire edge is your best friend when honing. It lets you know that you have honed across the bevel face to the back of the blade. So each time you finish a stone, remove the wire edge in preparation for the next stone. When you work the next stone, you do not stop until (a) the edge has polished out the scratches of the previous stone (not always easy to see with the naked eye), and (b) you raise a fresh wire edge denoting that you have honed right across the bevel face.

Regards from Perth

Derek

[Orlando Gonzalez]

Derek,

When you hollow grind a blade or chisel on your Tormek, to say 30*, do you set the angle guide to + or - 2* to get the flat in front of the hollow so you then can hone it to the 30* on your stones?

The reason for removing the wire edge on your finishing stone is because that is the last stone you lapped the back on and you do not want to introduce a lower grit scratch pattern on the lapped back?

Thanks

[Jonathan McCullough]

I sharpened a complete set of chisels recently. All but one of the chisels had a sort of concavity, not unlike Japanese chisels. On the first one or two I got the backs completely flat. It was a bit of a grind, if you'll forgive the pun. On the rest, rather than work hard, I decided to work smart, and embraced the fact that the oval concavity resulted in less work as well as a keen edge at the business end that was as good as if I had spent much more time getting the backs completely flat.

[Derek Cohen]

Derek,

When you hollow grind a blade or chisel on your Tormek, to say 30*, do you set the angle guide to + or - 2* to get the flat in front of the hollow so you then can hone it to the 30* on your stones?

The reason for removing the wire edge on your finishing stone is because that is the last stone you lapped the back on and you do not want to introduce a lower grit scratch pattern on the lapped back?

Thanks

Hi Orlando

The angle setter is an approximation which is enough accurary for me. I am not really that interested in the "perfect 30 degrees". I hone on the angle that is there.

And, yes, I hone the wire edge using the finishing stone as anything else would undermine the finish that already is there.

Regards from Perth

Derek

[Adam Cherubini]

Adam, I'm curious as to why you remove the coarse stone's wire edge on your finest stone before honing the bevel on the finer stone. Seems like most of the reommendations I encounter have you wait to wipe the wire edge until after you have honed the bevel on the finest stone. Does it matter?

Nelson
If you left the wire from the coarse stone, how would you know if you raised a wire on the finish stone? Sof for quick touch ups, I'm using 2 stones, soft arkansas and a hard arkansas. The dull bevel goes to the soft ark first. I hone until I've raised a wire edge. Then I clean up that stone and put it away. Get out my hard ark, clean the wire edge off the back, flip over to the bevel and hone until I raise a new burr.

If I hone for a while and still don't raise a burr, I guess that means my angle is too high. You either need to raise the tool, or hone away some meat on the coarser stone.

Adam

[Orlando Gonzalez]

Thanks Derek.

I wasn't clear on my grinding question. :o

What I meant to ask was since you don't grind to the edge, to prevent from damaging it and, thus, leave a small flat in front of the hollow towards the edge of the blade, how do you set up your Tormek grinding jig to achieve this small flat just before the edge. I think that it is this flat that you hone to the angle you want for that particular blade/chisel. I am currently grinding to the edge and want to change that.

Thanks again for the help.

[Derek Cohen]

Hi Orlando

On the Tormek I grind to the end of the bevel and create a wire edge. Only the Tormek can do this safely because it runs so cool. A dry grinder, even the best set up and with an experienced hand, cannot safely grind to the edge and must stop short.

By reducing the amount of steel at the edge one is able to create a true micro bevel and hone faster, even use fewer grits to do so. Further, I have not experienced the thinner edge being weaker than the thicker edge on a dry grinder.

When I hone I simply grind the hollow at an angle I desire, then freehand directly on this, using the hollow as the "jig". I do not create a secondary bevel (with the exception of BU planes blades, when I will use a honing guide).

Regards from Perth

Derek

[David Weaver]

This is helpful dialogue from folks with significant expertise. While you are here, I will chime in and say that I never seem to get a wire edge. I have used various honing jigs and Shapton stones from 1K to 16K, it just seems that no wire edge is appearing. What does this indicate? What is the secret to getting the elusive wire edge?

Thanks,
-John

You should get a wire edge with the more coarse stone, through an 8k stone if you're using a steel that has some toughness (the very high carbon low alloy stones will probably not give you a wire edge on an 8k stone, which may be why they "feel sharper"). You may need to feel it rather than look for it.

On a 16k stone, there shouldn't be much in terms of alloys where a wire edge stays on stubborn - the grit is too fine, and they come off (that is a good thing). You're essentially doing the same thing as a strop with the last stone, but with more accurate geometry.

i don't know, though, if there is a practical difference in durability between an edge off a shapton stone and a arkansas stoned edge that gets properly run across a strop. Someone would have to get a board and do a sample of each running a tool until it won't cut to be able to tell.

[Larry Williams]

The problem i have with this is the amount of metal that needs to be removed. Theoretically, a tiny wear bevel requires the removal of that depth across the entire back. I think one is better off working the smaller area of the bevel longer.

I used to sharpen the way Larry suggests and I got good edges, but it took me a while. I've seen Larry sharpen and it doesn't take him as long as it took me (and he doesn't use any exotic stones or anything). So I think this is a bit more complicated. He may be doing something, making judgements etc etc that isn't entirely clear in his post.....

Judgments? Yes, I make judgments. I have two goals each time I sharpen. First, of course, is to create a sharp edge. Just as important is the second goal of making sure I do everything I can to make my next sharpening easy. I do the prep work for my next sharpening each time I sharpen. I start and end the process with tool backs and stones that are repeatably flat and I manage the size of the honed bevel. I also avoid unnecessary paraphernalia that has to be set up or tinkered with.

The wear bevel on the back is longer along the length of a tool than it is deep into the thickness but it needs to be removed at each sharpening. On a tool I've sharpened before, just a few passes on a medium India stone is enough to remove the wear. It doesn't take much when your stones are cutting in the same location they were the last time the tool was sharpened.

If the honed portion of the bevel has grown to where I can't raise a wire edge with no more than five or six passes on the stones, I regrind. I always leave a slight amount of the old honed flat unless I have some damage I need to deal with.

We make a lot of irons in our shop and are constantly flattening and conditioning new irons. If it wasn't for this, I would have gotten bored with sharpening threads long ago. Maintaining the edge tools I work with is so easy and quick that I'd likely look at a sharpening thread and think, "Oh brother, what are they going on about now."

[Harlan Barnhart]

If the honed portion of the bevel has grown to where I can't raise a wire edge with no more than five or six passes on the stones, I regrind. I always leave a slight amount of the old honed flat unless I have some damage I need to deal with.

This is something I need to learn. My 1000 waterstone is wearing out insanely fast. I must be over using it.

[george wilson]

Harlan,a medium India stone is a lot harder,and is much coarser than your 1000 grit water stone. Maybe you should get one instead of wearing out the waterstone for beginning to sharpen an edge.

[Nelson Howe]

As always, more good information here. I have been be free handing. Rather than honing away the wire edge from my coarser stone on the finest stone, I have been honing until I feel wire edge get appreciably smaller, which I have taken to mean it has been replaced by the smaller wire edge appropriate to that finer stone. I will try your recomendations and see if it works better for me. Do you find it makes a difference which direction you stroke the tool to remove the wire edge?

I use an 8" white wheel on a 1720 rpm grinder, and I regularly grind away right to the edge without burning it, though I dunk often. I thought it made my stop on the 800 water stone a briefer one than if I didn't already have the rougher wire edge from the grinder. Are there advantages other than not burning the edge to refraining from grinding it all away?

Nelson

[David Weaver]

As always, more good information here. I have been be free handing. Rather than honing away the wire edge from my coarser stone on the finest stone, I have been honing until I feel wire edge get appreciably smaller, which I have taken to mean it has been replaced by the smaller wire edge appropriate to that finer stone. I will try your recomendations and see if it works better for me. Do you find it makes a difference which direction you stroke the tool to remove the wire edge?

I use an 8" white wheel on a 1720 rpm grinder, and I regularly grind away right to the edge without burning it, though I dunk often. I thought it made my stop on the 800 water stone a briefer one than if I didn't already have the rougher wire edge from the grinder. Are there advantages other than not burning the edge to refraining from grinding it all away?

Nelson

If you do manage to never burn an edge, there still is an advantage that your wear at the edge (if you don't grind all the way to it) is always with your honing tools, and not the grinding tools. It'll make an appreciable difference in life of the iron or chisel that you're using.

Whether or not that's material for a hobbyist, I don't know.

I haven't come remotely close to wearing anything out. I have enough trouble just even getting to the edge of a hollow on a japanese tool, and that's a small fraction of the length of usable steel.