Wear bevel?

[Michael J Evans]

Tonight I could not get a burr on a plane iron I was sharpening, it also would not get sharp even after extensive time on the fine stones.

I normally gauge sharpness by how easy the edge shaves hair. I consider very sharp to be shaving with no resistance.

Anywhoo upon visually inspecting the iron, I noticed a very small band of light right below the cutting edge on the back side of the iron (flat side w/o bevel). It was very very small and much more shiny then what I had polished the back of that iron to.

Is this what's known as the wear bevel, and does it have to be removed to get back to sharp?

Thank you
Michael

[ken hatch]

Tonight I could not get a burr on a plane iron I was sharpening, it also would not get sharp even after extensive time on the fine stones.

I normally gauge sharpness by how easy the edge shaves hair. I consider very sharp to be shaving with no resistance.

Anywhoo upon visually inspecting the iron, I noticed a very small band of light right below the cutting edge on the back side of the iron (flat side w/o bevel). It was very very small and much more shiny then what I had polished the back of that iron to.

Is this what's known as the wear bevel, and does it have to be removed to get back to sharp?

Thank you
Michael

Michael,

Yep, it does

ken

[William Fretwell]

What Ken said.

[Robert Hazelwood]

What you are describing sounds exactly like a wear bevel. The wear bevel prevents you from fully removing the burr when you work the back on a stone. But it should not prevent a burr from forming when you work the bevel side.

If you did not raise a burr then something is going on with the bevel side. Maybe you weren't sharpening at quite the right angle or did not go quite long enough with the coarse/medium stones. The edge could have been dubbed during a previous sharpening and now it requires a lot more work at the normal angle to get back to the edge.

If you have a grinder, it might be a good time to grind the bevel back almost to the edge. That will make it easier to quickly raise a burr.

To remove the wear bevel, work the back (just the portion at the very edge) on a medium-fine stone (I use a soft arkansas, a ~4000-grit waterstone would also work) for 10-20 seconds or until you can no longer see the shiny strip at the edge. Then restore the polish with the fine stone.

[ken hatch]

Michael,

If you want to really get into the sharpening weeds https://brentbeach.ca/Sharpen/bevels.html


(https://brentbeach.ca/Sharpen/bevels.html)

[Winston Chang]

I wrote something about wear bevels and burr here: https://sawmillcreek.org/showthread.php?286912-I-m-confused&p=3067179

[Robert Hazelwood]

Winston's linked post has some great info and scope pictures of the wear bevel. But I think the wear bevel is not the immediate concern for the OP. He is somehow not managing to sharpen all the way to the tip when working the bevel, so that a burr is never formed in the first place.

[Jim Koepke]

Tonight I could not get a burr on a plane iron I was sharpening, it also would not get sharp even after extensive time on the fine stones.

I normally gauge sharpness by how easy the edge shaves hair. I consider very sharp to be shaving with no resistance.

Anywhoo upon visually inspecting the iron, I noticed a very small band of light right below the cutting edge on the back side of the iron (flat side w/o bevel). It was very very small and much more shiny then what I had polished the back of that iron to.

Is this what's known as the wear bevel, and does it have to be removed to get back to sharp?

Thank you
Michael

If a plane iron has been used for an extensive time without honing it is likely to develop an extended wear bevel.

This will require extensive time on coarse stones before moving to the finer stones.

This is a blessing turned curse on some premium blades. The wear profile is smooth. Most of my older blades tend to wear with small chips in the edge. This reveals the wear in an obvious way. Those that wear without chipping tend to tempt me into going longer between honing. This will produce more of a wear bevel in need of attention.

Some address this with "the ruler trick." This may cause more of a wear bevel to contend with in the future when the blade is honed.

Others find sharpening at the earliest signs of edge wear will make for a smaller wear bevel to contend with when honing the bevel side of a blade.

jtk

[Michael J Evans]

The wear bevel was definitely the issue.
I tried to start with a course crystolon but after a couple minutes gave up.
Decided to bust out the 80 grit PSA and that took care of the grinding portion in short order. Went back up the grits and everything is all good now.

Thanks for all the replies and interesting reads.

Michael

[Jim Matthews]

See David Charlesworth's "ruler trick".

It's an amazing time saver.

[Warren Mickley]

See David Charlesworth's "ruler trick".

It's an amazing time saver.

The ruler trick will work the first time, a one trick pony. Then if you get a large wear bevel again, the ruler trick bevel will have to be lengthened in order to erase the new wear bevel. The ruler trick bevel is so shallow that the change in length (of the trick bevel) is 86 times the depth that is worn away.

[Tom M King]

I never use the ruler trick on anything.

[Robert Hazelwood]

The wear bevel was definitely the issue.
I tried to start with a course crystolon but after a couple minutes gave up.
Decided to bust out the 80 grit PSA and that took care of the grinding portion in short order. Went back up the grits and everything is all good now.

Thanks for all the replies and interesting reads.

Michael

You were grinding the bevel side? One way to remove a wear bevel is to remove a lot of material from the bevel, moving the edge back past the wear. That probably also fixed whatever wear or geometry issue you had on the bevel side.

80 grit PSA is excellent stuff.

[Jim Matthews]

There are those that consider methods not published in the sanctified encyclical of Roubo to be heretical.

The rest of us just want to get on with it, already.
(We even use power tools instead of indentured servants.)

[Charles Guest]

Hone the bevel past the wear, then back off the nice fat burr you worked up as you normally would. Don't wait so long to hone next time. Chisels and plane irons are wasting assets. They are not meant to last three lifetimes. Your goal is to use them up. I'm not suggesting abuse but I'm also not suggesting that using a chisel down to a nub is something to be ashamed of. Quite the opposite.

[Jim Koepke]

Hone the bevel past the wear, then back off the nice fat burr you worked up as you normally would. Don't wait so long to hone next time. Chisels and plane irons are wasting assets. They are not meant to last three lifetimes. Your goal is to use them up. I'm not suggesting abuse but I'm also not suggesting that using a chisel down to a nub is something to be ashamed of. Quite the opposite.

Have there been any studies on if a wear bevel tends to grow faster as the blade wears?

It seems to follow logically that as the wear bevel starts it increases the angle/resistance of the blade.

This would also provide a very good reason to sharpen more often.

jtk

[Michael J Evans]

I guess I'm missing the boat on either sharpening and or honing at the correct angle.
I feel like I sharpen frequently and try to stay sharp.So it must be sharpening angle? I generally free hand and try to be quick about it and don't worry to much about angles. I really only about getting a burr and getting sharp.

[steven c newman]

yep..there are some on here that think one needs a "Phd" in Sharpening.....

[Derek Cohen]

I am late to this thread, but a few comments ...

The wear bevel is real and can become an issue ... bit rarely is. It is more of a factor with bevel up planes, since the wear bevel can reduce the clearance angle, and too little clearance will cause a place to stop cutting. But, then again, this is rare.

I used to hotly debate this issue with Larry Williams (Old Street Tools and planes), who was anti BU planes and I pro BU planes. We used to have some fine arguments .. uh ... debates, especially on the FWW forum. History is the judge. BU planes have been very popular for decades now, and how many users complain about the wear bevel? The few that do are notable to have abused their plane and blade. That is, used it too long and let it get too dull, then blamed the wear bevel; failed to prepare the back of the blade when the honed the bevel face; or, simply hammered the blade with too-deep cuts.

Surely everyone hones the back of the blade each time they hone the bevel face? Even a light stop on the back to remove the wire will prevent a wear bevel intruding.

Regards from Perth

Derek

[Michael J Evans]

Derek
I wouldn't say I generally hone the back. Generally I pull it a few times across the stone to loosen the burr. Like I said a few times.
Maybe part of the issue is I haven't flattened the backs to the umteenth level of polish?. I think on this blade I flattened the back to around 600 grit or so and stopped. Spending hours flattening backs is no fun to me.

[Michael J Evans]

And this is a bevel down plane.

[Jim Koepke]

I guess I'm missing the boat on either sharpening and or honing at the correct angle.
I feel like I sharpen frequently and try to stay sharp.So it must be sharpening angle? I generally free hand and try to be quick about it and don't worry to much about angles. I really only about getting a burr and getting sharp.


Derek
I wouldn't say I generally hone the back. Generally I pull it a few times across the stone to loosen the burr. Like I said a few times.
Maybe part of the issue is I haven't flattened the backs to the umteenth level of polish?. I think on this blade I flattened the back to around 600 grit or so and stopped. Spending hours flattening backs is no fun to me.


And this is a bevel down plane.

Not worrying about the angle has two sides to it. In my case, not worrying about the angle means the angle of a particular chisel or plane blade may not be known. My worry is about maintaining the angle. My intent during sharpening is to avoid a secondary angle. They still creep in at times.

For others working with a secondary bevel may be their preferred choice. Then it can be a little more difficult to maintain a constant angle without a guide. This can lead to an ever increasing working angle at the arris. With a bevel down plane if this angle becomes more than 35º it can cause the blade to 'roll' over the wood.

jtk

[Robert Hazelwood]

I guess I'm missing the boat on either sharpening and or honing at the correct angle.
I feel like I sharpen frequently and try to stay sharp.So it must be sharpening angle? I generally free hand and try to be quick about it and don't worry to much about angles. I really only about getting a burr and getting sharp.

I think what happened is that on a previous sharpening you may have accidentally honed the bevel a bit too steep - let's say you did a few strokes at 38 degrees. Then, on the sharpening that gave you problems you were probably trying to hone at a more normal angle like 33 degrees. In order to raise a burr, you would need to sharpen long enough at 33 degrees to remove the entire 38 degree bevel, and you were struggling to do that on your normal stones. Getting out the 80 grit and grinding the bevel side is what fixed the problem (incorrect geometry on the bevel side).

As I said before, the wear bevel is on the back of an iron, and will not prevent a burr from forming when you sharpen/grind the bevel side. No matter how big it is. If you can't raise a burr then there's some issue with the bevel side geometry. What the wear bevel does is impede full removal of the burr after its formed, a separate issue.

[Michael J Evans]

Thanks Robert