My Camber Blade Round Tuit Finally Came

[Jim Koepke]

OK, a couple of times I have said this would get done. Here it is in all of its rambling words and pictures.

Sharpening is one of those things that gives rise to many opinions and heartfelt debate over preferred methods. There is also a lot of discussion of cambering blades.

My experience is limited in this area. I make no claim to be an expert. In my opinion, if your sharpening is working for you, then you must be doing something right. In the last few years my sharpening has become much better. Hopefully it will continue to improve over the coming years.

This post is only my opinion on another method for cambering a plane blade. Most of the time my blades are not purposely cambered. If my lumber came with a rough surface, then a blade might be cambered to use like a scrub plane. If my work was in more expensive woods and making fine high priced furniture, then my blades might get cambered for the final smoothing.

Please offer your comments, suggestions, experiences and ideas in the spirit of "this is what works in my shop." If you have tried these or different methods and they have had problems or successes that you can share, it will make it more interesting and add value for all who read this thread.

Before anything else, the blade must be sharp. The definition of sharpness can be quantified, but the actual physical being of sharpness seems to be a moving target as we become more skilled at sharpening.

Testing for sharpness is also an area of wide debate.

Some will claim they can tell if a blade is sharp enough by testing against their thumbnail.

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They are correct. It does take some time to learn this method of sharpness testing. It also is not a good one to use if you have a propensity to keep the free edge of your nails trimmed.

In my experience the sharpness can be determined by the feel of the edge against the nail and the angle at which it must be held to "stick." It is also possible to get the edge to "stick" without being fully sharp. This is where experience comes in with every test mentioned here.

Another method that is often mentioned is the push through paper test. This is perhaps the safest way to check for sharpness. As long as fingers and other flesh are kept out of the path of the blade there will likely be no mishaps.

180199

The less stiffness in the paper, the sharper the blade needs to be. Also, a slicing motion is kind of like cheating. To test sharpness it must be a straight push into the edge of the paper.

I do not use this test, but it is a good and safe way to test a blade's edge.

I didn't take any pictures of the hair shaving method of testing the edge of a blade. Though this is my most used way to test a blade, it can be dangerous. It may be that when young, it was my habit of not shaving for a few years at a time that lead me to use a straight razor. In those days we didn't have the multi bladed razors that are common today. The confidence of dragging one of those across my neck may be why pushing a chisel or plane blade across my arm doesn't seem out of the norm for me.

Like the paper or thumbnail test, there are different levels of sharpness that can be detected by the arm hair test. A really sharp blade will not leave any hair in its path and you will not feel hair being cut.

The end grain test also was not photographed. A sharp blade should be able to take a very fine shaving from the end grain of pine or other soft wood. In a plane, if it takes a fine shaving, it is probably sharp. Otherwise, what one often gets is dust or a need to take a thick shaving.

Why camber a blade?

This is an often asked question. For a scrub plane it is obvious, it is easier to get to the wanted thickness and remove saw marks planing diagonally or across the grain with a deep cut. A cambered blade helps with hogging off wood in these situations.

Some like a slight camber across the full width of their jointer planes. This is something for someone who uses such to add if they choose. It is something of which the theory is understandable and has its appeal. The theory of time travel is also appealing, it is just that neither have happened for me as of yet.

For many people a slight camber at the edge of a smoother plane is helpful in eliminating "tracks" sometimes left by the corner of a plane's blade.

Methods to camber a blade are likely as plentiful as the ways to sharpen a blade if not more so.

My thoughts on this come from my experience while flattening the backs of old blades that would come up great in the center but not the edges. Maybe that was because craftsmen of years gone by also relieved the backs of the blade at the edges.

This is what the shaving looked like from a freshly sharpened blade mounted in a #5 type 17 before being "cambered."

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Please note this shaving was taken on a scrap of wood used for testing gouges and knife blades. The area of the shaving on the ruler was not affected by previous tests. The areas where the shaving is broken are where there were depressions in the surface from previous tests.

Here a small stone is used to emphasize this being done in just a corner of the blade. It only takes a few strokes. It will even go faster if done on a coarser stone.

180204

One "camber" was done on the back of the blade and a second was done on the bevel side for comparison purposes.

180203

The honing of the camber is done at an angle. This will tend to feather the edge so the camber will be most at the edge and diminish towards the center of the blade. In total it was less than 10 short strokes on either side of the blade. YMMV

The blade was reinserted into the plane and adjusted to take a similar cut.

180200

The shaving is not the full 2" at about the same shaving thickness. Running one's fingers over the planed surface does reveal that the edge of the blade being cambered does make a difference in the surface. YMMV

One of my bevel up block planes has a blade that has the underside of the blade corners relieved. It is similar in action.

In my opinion, if one wanted to "camber" the blade on a bevel up plane, a slight honing on the corners of the "blade's back" might be an attractive alternative.

jtk

[john brenton]

On a lot of the old irons I pick up I too have noticed a full radius so slight that you don't even see it until you start polishing. I've noted it on the bevel side, but not too ofter on the back, although I have seen it. I figured it was just the way it was made and never flattened. The first few irons I had like that I worked the camber off...then after learning more about camber I worked with the radius and discovered that they had the perfect (IMO) grind/shape.

Kind of hearkens back to a comment Adam Cherubini made in a post about a month ago. Sometimes the iron or chisel has a strange grind because the previous owner didn't know what they were doing, but sometimes it's because the previous owner knew what we want to know.

One great use for a more dramatic radius that is new to me is in edge jointing. I had never thought about it but had read it in a book, or a blog or something. On an edge that's warped, or an edge that I've accidently planed out of square, the cambered iron levels it out in a few controlled strokes with the jack or jointer fittied with the heavy cambered iron, as opposed to running the jointer over and over again and getting minimal results. You can more easily focus your efforts on the high side, and the camber of course lets you hog out more. Tear out can suck though, but I don't let it get too close to level before I use the jointer again.

Cool post Jim.

[george wilson]

Yep,that looks sharp!!!

[john brenton]

I see we're all having an exciting Friday night...

[Mark Baldwin III]

I see we're all having an exciting Friday night...

No energy left to spend in the shop working (long week at work). Next best thing is some tunes, a good pint of porter, and reading about how to be a better woodworker.

[Mark Baldwin III]

How do you find your sharpening methods to differ between planes and chisels? I can make any one of my planes sing with little effort. Even my beat up 50ish year old Stanley can take the finest shavings. Ask me to sharpen a chisel, and it's all done. For whatever reason, I can't get my chisels anywhere near as sharp as my planes. I'm starting to believe that it's the chisels and not me (my bench chisels at the moment are Footprints). I want to get a few LN's and Blue Spruce chisels, and ditch my footies...I can't believe that they're THAT bad though!

[Chris Griggs]

How do you find your sharpening methods to differ between planes and chisels? I can make any one of my planes sing with little effort. Even my beat up 50ish year old Stanley can take the finest shavings. Ask me to sharpen a chisel, and it's all done. For whatever reason, I can't get my chisels anywhere near as sharp as my planes. I'm starting to believe that it's the chisels and not me (my bench chisels at the moment are Footprints). I want to get a few LN's and Blue Spruce chisels, and ditch my footies...I can't believe that they're THAT bad though!

I have had that same experience. While I try to never blame the tool, I'm becoming fairly certain that my woodriver chisels just can't get a sharp edge as easily as a hock or old stanley blade.

Hopefully I can pick up some AIs or LNs in the near future.

[john brenton]

It's going to sound like a silly thing to say, but I have the Footprints and I can effortlessly pare end grain with one hand with them...not that I do that on the daily or anything, but sometimes I do pointless stuff when I'm taking a beer break in the man cave.

Although I never experienced a problem with not being able to get chisels as sharp as plane irons, I do suggest the veritas honing jig...or any honing jig, but the veritas is the one I have. It does make sharpening more exact, and it makes adding the secondary bevel a cinch. Maybe there is a certain degree of ultra-sharpness, or fineness that I feel on an old iron that I don't feel on a new chisel...but perhaps it could be slightly lower bevel angle, the composition of the iron, or just my imagination. Either way, the sharpness of the chisels doesn't leave me wanting more.



How do you find your sharpening methods to differ between planes and chisels? I can make any one of my planes sing with little effort. Even my beat up 50ish year old Stanley can take the finest shavings. Ask me to sharpen a chisel, and it's all done. For whatever reason, I can't get my chisels anywhere near as sharp as my planes. I'm starting to believe that it's the chisels and not me (my bench chisels at the moment are Footprints). I want to get a few LN's and Blue Spruce chisels, and ditch my footies...I can't believe that they're THAT bad though!

[Russell Sansom]

We'd probably have to understand you sharpening method to guess why you can't get chisels sharp. One reason might be chrome vanadium steel. I've learned to steer completely clear of it. Otherwise, if you know what sharp is on a plane iron, why can't you get the same thing on a chisel? Softer steels should sharpen right up.

[Mark Baldwin III]

These sharpening threads are some of my favorites to read. I learn a little something from each one. Think I'll have to give my plane irons a little attention this weekend, and try out Jim's technique. I use a LV jig for 99% of my sharpening. Some on waterstones and some on sandpaper, depends on my mood really. Glad to accept that the problem is me, and not my tools. I'll have to try an extra dose of patience!

[Chris Griggs]

I should have been more clear with my original response to Mark's post. While I CAN get them as sharp as my plane irons (pare pine end grain or shave hair) I find it to be more difficult to consistently get a good edge ( i use an eclipse for all my sharpening).

I believe my chisels (WR) are probably a low quality A2 or other steel with chromium that if not made to high standards has issues with large uneven carbides (not that i really know what I'm talking about when it comes to steel types). .

Though they've been a perfectly usable starter set, especially give how cheap they were, they chip relatively easily (honed at 35 degrees)

Actually come to think of it, my issue with sharpening them is probably due to the fact that A. they are a harder steel than most my plane irons and B. the edge fractures easily and therefore there is typically more work to be done when I re-sharpen them than there is when I re-sharpen my plane irons.

[Jim Koepke]

While I CAN get them as sharp as my plane irons (pare pine end grain or shave hair) I find it to be more difficult to consistently get a good edge ( i use an eclipse for all my sharpening).

I believe my chisels (WR) are probably a low quality A2 or other steel with chromium that if not made to high standards has issues with large uneven carbides (not that i really know what I'm talking about when it comes to steel types). .

Though they've been a perfectly usable starter set, especially give how cheap they were, they chip relatively easily (honed at 35 degrees)

Actually come to think of it, my issue with sharpening them is probably due to the fact that A. they are a harder steel than most my plane irons and B. the edge fractures easily and therefore there is typically more work to be done when I re-sharpen them than there is when I re-sharpen my plane irons.

It seems there are two main problems addressed in this. One is the ability to achieve a sharp edge. The second is to keep the sharp edge.

Is the full bevel at 35º or is that a micro bevel?

What you have left out may also be important. What is your sharpening media?

Another important consideration is how many times have the blades been sharpenend?

Also do you strop your blades after sharpening or between sharpenings?

Until reading about it, in a book by Chris Pye and a lot of others who use it here, it was not a part of my arsenal. My wife likes to do lapidary. To the rest of us she likes to play with rocks. When we were in a store picking up some supplies for her, I noticed they had some green charging sticks for polishing stones. It does wonders to my blades on hard leather. Used between sharpening sessions, it helps a bit to maintain an edge. The blade needs to be stropped before it gets noticeably dull. I use this mostly on chisels. Too much hassle with plane blades to disassemble a plane and cap iron. I do sharpen plane blades before they get really dull. Plane blades do get stropped at the end of their sharpening on stones.

The chiping of the edge is something that happened to me with a brand new blade of A2 steel. Now that the blade has been honed a few times, the problem seems to have gone away. This small chip would always appear at the same spot on the blade.

Is just happening to one blade in a group? Is it a lot of chipping in different locations or is it always in the same spot? I think A2 steels do have a tendency to fracture at the edge as opposed to rounding.

As to blade hardness, it is my opinion that even old Stanley blades came in different degrees of hardness due to the differences in workers and supplies.

Two of my blades with the same logo have very different characteristics when it is time to sharpen them. One just comes up fine and dandy. The other wears me out trying to give it an edge. Maybe next time I will try to determine if one holds the edge better than the other.

Another question would be, do you have any power grinding equipment? Sometimes it can be helpful in getting a good edge on a blade. Other times it can be a curse if you "burn" the edge.

I do not have a bench grinder, but they do help make it easier for folks who like to sharpen by hand. The hollow grind makes it much easier to get the edge registered on the sharpening media.

I use a flat disk power sharpening system that has made me very happy. (Veritas Mk II Power Sharpening system) That can be quite an investment. There are only a few things in my shop that have not been able to be sharpened on this. Only one of those items might benefit by having a wheel grinder.

Well this is getting a bit rambly.

If you have more questions, ask them. That may be the only way to find an answer.

jtk

[Chris Griggs]

In response to Jim's questions...

- the 35 degree bevel is a secondary/micro bevel.

- I've had the chisels over a year so they've been sharpened a number of times. They have definitely gotten better with more sharpenings which tells me that the initial grinding did in all likelihood remove some of the temper in the very tip. Perhaps not all of this has been removed yet and hopefully they will continue to improve with time.

- I don't have a power grinder. When I need to regrind the primary bevel I switch over to course sandpaper on granite, so I'm fairly certain that I couldn't have affected the steels temper.

- My primary sharpening medium is 1000 to 8000 norton waterstones. I typically follow with a few swipes on mdf loaded with the green stuff (still haven't decided if this makes a difference). I don't strop between sharpenings, but I do resharpen fairly frequently, as I love working with a fresh edge.

- Haven't noticed if the chisels chip in the same place; that's definitely something I'll pay attention too.

- Also before someone asks this question. Yes, that backs are flat and polished to just as a high a polish as the bevel.

Honestly, my issue might partially be that I'm just a bit too OCD when it comes to sharpening (if there is such a thing) and edge retention. As we all know, sometimes REALLY sharp just isn't sharp enough.

And once again, while the chisels are perfectly functional, they are still relatively low end so it wouldn't surprise me if the steel is of less than stellar quality.

Hope that answers all your questions Jim; thanks for the input.

[Jim Koepke]

Honestly, my issue might partially be that I'm just a bit too OCD when it comes to sharpening (if there is such a thing) and edge retention. As we all know, sometimes REALLY sharp just isn't sharp enough.

And once again, while the chisels are perfectly functional, they are still relatively low end so it wouldn't surprise me if the steel is of less than stellar quality.

Hope that answers all your questions Jim; thanks for the input.

That does pretty much answer the questions.

One of my thoughts on a sharp edge is that each time it cuts something it is dulled by the cutting action. Even testing the sharpness does a little to dull a blade. If this didn't happen, we could have blades that never dulled.

The pursuit is finding a blade that holds an edge long enough so we can do enough work so that the sharpening seems like a quick break from the more difficult work at hand.

I keep a couple of pieces of leather charged with green stropping compound. The trick is to strop a few strokes before the chisel really needs it. When it is clearly apparent that it is needed, it is too late for it to help much.

jtk

[Eric Rathhaus]

Hi I put a camber on my iron but have a hell of a time honing it to sharp. Here are some pictures. Is my arc too big? Did I lift up too much and round the edge over?436059436060436061

[ken hatch]

Hi I put a camber on my iron but have a hell of a time honing it to sharp. Here are some pictures. Is my arc too big? Did I lift up too much and round the edge over?436059436060436061

Eric,

it depends on what you want to use the cutter for. For smoothing it is too much. I use slightly less on my jack but more on a scrub.

ken

[Jim Koepke]

It looks like you have the shape good for using as a scrub blade.

Though it looks like there isn't much of a bevel on the edge.

One of my scrub blades, on a #5-1/4, looked like this in the beginning. At first it was sharpened only in the center and the bevel was increased with each sharpening after that.

jtk

[Eric Rathhaus]

Thanks Ken and Jim. I think the picture is slightly deceptive regarding how much bevel is there. At first, the bevel just before the edge began to look almost perpendicular to the back. But when I reground the blade and concentrated on lifting less, I couldn't;t ever raise a burr. Maybe I just need to keep at it. I just don't wan't to destroy the iron in the process. It's a pretty good EA Berg iron.

[Jim Koepke]

Have you tried it in a plane to see how it works?

jtk

[Eric Rathhaus]

Jim, we've reached the bigger issue. I was having some problems using the plane. Learning at home alone one of the biggest challenges to diagnosing causes. I kept getting shaving/saw dust stuck between the blade and mouth. My diagnosis, blade chip breaker set needs refining and mouth needs some smoothing. My process was to get the blade ready, work on the chip breaker to get a good fit, and then file the rough spots off the mouth. Since I've altered the blade, I need to work on the chip breaker but am hesitant to start until I know how the blade will end up. Does this make sense? I could drop it in, but the chip breaker hasn't; been cambered.

[ken hatch]

Jim, we've reached the bigger issue. I was having some problems using the plane. Learning at home alone one of the biggest challenges to diagnosing causes. I kept getting shaving/saw dust stuck between the blade and mouth. My diagnosis, blade chip breaker set needs refining and mouth needs some smoothing. My process was to get the blade ready, work on the chip breaker to get a good fit, and then file the rough spots off the mouth. Since I've altered the blade, I need to work on the chip breaker but am hesitant to start until I know how the blade will end up. Does this make sense? I could drop it in, but the chip breaker hasn't; been cambered.

Eric,

The cap iron should not be cambered.

ken

[Eric Rathhaus]

Even if the corners protrude past the profile of the iron?

[Erich Weidner]

Even if the corners protrude past the profile of the iron?


I'm wondering this as well. On my #4 smoother I very lightly cambered the blade. Putting the chip breaker up as close as I've read I'm supposed to (1/64" to the edge)... the corners of the chip breaker seem to be leaving tracks on the work.

[Bob Jones 5443]

Seems there’s some mystery surrounding sharpening and the camber in particular.

Goodness knows I’m no expert, but if you want to build the skills to sharpen perfectly and quickly, every time, I recommend picking up David Charlesworth’s plane-iron sharpening video through Lie-Nielsen. He explains everything clearly and patiently, from flattening the back of a new iron to honing and polishing the secondary bevel. Then he shows a fast, foolproof method to camber the iron.

The basic camber in question is for what most of us want from a smoother or Jack, when flattening a board or squaring an edge. (But that is for another day.) A scrub plane would use a more pronounced camber, and that too can be had by taking David’s method just a few steps farther.

He finishes by teaching a marvelously simple two-minute resharpening process of a cambered iron.

Materials needed:
- the video, $30
- Eclipse-type honing jig, $15
- a way to measure angles of the iron in the jig. I used a 5 x 8 stiff cardboard cutout for years; requires a $2 plastic protractor and an Exacto (or marking) knife. A 150 mm metal ruler helps speed up repeat settings.
- 800 (or 1000), 4000, and 8000 waterstones (the most expensive part, about $125 for Norton’s beginner paired set)
- Nagura stone, about $12
- 220 wet/dry sandpaper, $0.80 a sheet
- 9 x 12 float glass, 1/2” thick, maybe $25 from a glass supplier

Entire kit is about the cost of four premium plane irons, and you can even find less expensive waterstones to cut the cost further.

David’s methods (think “ruler trick”) are the real deal, have been around for decades, and have spawned many household-name exponents repackaging his wisdom. But it’s all there in one video. As the saying goes, “some things that should not have been forgotten were lost. History became legend. Legend became myth. And for two and a half thousand years, the ring passed out of all knowledge.” And then there was YouTube.

It will take you a few hours to go carefully through the 90-minute video, and then maybe several more hours to take notes and then perfect the method, but once you invest the time you have a lifelong skill that lets you consistently, confidently achieve precise, predictable, reproducible sharpness.

[Jim Koepke]

Jim, we've reached the bigger issue. I was having some problems using the plane. Learning at home alone one of the biggest challenges to diagnosing causes. I kept getting shaving/saw dust stuck between the blade and mouth. My diagnosis, blade chip breaker set needs refining and mouth needs some smoothing. My process was to get the blade ready, work on the chip breaker to get a good fit, and then file the rough spots off the mouth. Since I've altered the blade, I need to work on the chip breaker but am hesitant to start until I know how the blade will end up. Does this make sense? I could drop it in, but the chip breaker hasn't; been cambered.


Eric,

The cap iron should not be cambered.

ken

Cambering the cap iron is not necessary for setting up as a scrub plane. On a cambered iron for smoothing, there shouldn't be so much camber to the iron that the cap iron needs to be cambered to match.


Even if the corners protrude past the profile of the iron?


I'm wondering this as well. On my #4 smoother I very lightly cambered the blade. Putting the chip breaker up as close as I've read I'm supposed to (1/64" to the edge)... the corners of the chip breaker seem to be leaving tracks on the work.

1/64" is ~0.015", if the corners of the chip breaker are leaving tracks, that is much too thick of a shaving for smoothing. If the edge on a blade is straight, the chip breaker is set as close as a few thousandths of an inch to the edge. Then only if you are taking shavings of about a thousandth of an inch. Many users simply give an extra stroke on their finishing stone to the corners of their blade to produce a very subtle camber.

Here is an image from the first post in this thread:

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The 2" blade has almost no camber. The edges of the shaving virtually disappear.

The chip breaker should be set for the thickness of shaving one will be taking. A thick shaving will clog if the chip breaker is set for a thin shaving. A thin shaving may produce tear out if the chip breaker is set too far back.

These blades are for scrub plane use:

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The chip breaker is set behind the edge of the cambered blades. Setting the chip breaker closer will cause shavings to catch at the corners of the chip breaker. The blade on the right if from a #40 which doesn't use a chip breaker.



From my experience having an almost perfectly straight edge on my blade and taking a very thin shaving can be done without leaving any tracks. This was not something that came to me immediately. It took time and a lot of practice.

Some folks do camber their chip breakers. IMO, this is something to save until one has much more experience with hand planes.

jtk

[Eric Rathhaus]

Well II did drop it into the plane and give it a try. Like planing with a supine spoon. Definitely not sharp :) I'll work on it some more.

[Tom Vanzant]

Eric, I see three possible problems. 1) If the corners of the chip breaker extend past the cutting edge, they will cause “tracks”. Re-set the CB. 2) If the bevel approaches 45 deg, the heel of the bevel will ride on the surface of the wood, not the cutting edge. Re-grind/hone the bevel to 30-35 deg. 3) The produced shaving is too thick, and jams in the mouth (between the iron and the front of the mouth). Move the frog to the rear .015-.030”. Make sure the cutting edge is shaving-sharp. Good luck.

[Eric Rathhaus]

As an update, I went back to measure the angle on the bevel. I must have really rolled over the edge because it was dramatically more than the 32 degrees I had ground. Back to the grinder to set an appropriate angle and then hone again. wish me luck!

[Jim Koepke]

[edited]
The chip breaker is set behind the edge of the cambered blades.


One note on this. Setting the chip breaker as stated above may cause difficulty adjusting the blade's cutting depth if the iron has been overly cambered.

With a little fiddling using the plane being modified one could likely determine the maximum set back of the chip breaker. This would also indicate the maximum depth of the blades arc of camber.

jtk

[Eric Rathhaus]

Jim, happy to report that after grinding a new bevel at 30 degrees, I was able to get the blade sharp and spend the afternoon planning down the rough boardsI'll be suing for my bench top. Next up, figuring out how to use the ECE jointer. Thanks everyone.

[Jim Koepke]

Good to hear.


I'll be suing for my bench top.

Hopefully your lawyer won't cost too much. :eek:

jtk