Secondary bevel on chisels vs bevel-riding cuts

[Wayne Cannon]

I've been honing flat backs and flat bevels on all of my chisels for as long as I can remember. To the best of my understanding, a secondary bevel, or a hollow-ground bevel (off of a wheel) makes it very difficult to do bevel-down work, such as flattening the bottom of a hinge mortise, where you "ride the bevel". It seems that a hollow-grind would tend to dive into the wood, and that a secondary bevel would require tilting the blade up off of the primary bevel and onto the miniscule secondary bevel where you have less control.

I've seen so much about honing a secondary bevel on chisels and planes in the last few years, including jigs to repeatably set a secondary bevel angle, that I wonder what I'm missing. I understand that this makes honing a chisel a much faster operation, but it seems to limit chisel work to bevel-up work or coarse bevel-down work.

What am I missing, besides the time lost honing the entire bevel every time?

[Sam Takeuchi]

Micro bevel doesn't need to be wide. It can be as wide as a human hair or two. I don't know how a chisel would react with hollow grind though when used in that fashion.

[Dan Barr]

i recommend continuing with flat faces and flat bevels. period.

this whole micro bevel thing is over-rated. the only instance i know of where it might prove "slightly" valuable is with mortice chisels. (a 30 degree initial bevel followed by a 35 degree microbevel)

this allows the initial bevel to penetrate farther into the wood and therefore you can chop mortices "more efficiently". also, the micro bevel will supposedly stay sharper longer because its at a higher angle.

i still don't buy it. if anything, i prefer the flat bevel because when i go to re-hone, i don't want to be there all day trying to get past an old micro bevel.

otherwise, while youre honing off that initial bevel wondering what youre actually doing (because youre making little progress on the initial bevel; that micro bevel is still there) you might realize that re-grinding a new bevel every time you hone is wasting the steel that was apportioned to the blade in the first place.

also, this smacks of not knowing what youre doing in the first place. if youre good at sharpening, then shouldnt the initial bevel be sufficient? what is the real need for a micro bevel? beyond me...

sharpening twice just doesnt make any sense to me.

my two cents,

dan

[John Keeton]

I have used a microbevel on plane blades, and I think that use is acceptable and, in some cases, preferable. But, on chisels I agree with Dan. I see no advantage, and several disadvantages. And, it takes just a couple of minutes to touch up a chisel at full bevel - hardly any time savings.

[Robert Rozaieski]

Hollow grinding does not affect the ability to use a chisel bevel down. Only the center of the bevel is hollow, and not by a whole lot. There is still a heel of the bevel that is honed at the same rate as the tip of the bevel. This allows you to still ride the bevel when paring bevel down. Theoretically, it could be problematic in really thin stock, but I've never noticed a problem in actual use.

The two honed areas (heel and tip of bevel) continue to get wider and wider as you continuously hone, until they eventualy meet, effectively creating a flat bevel. When you get to this point, you regrind the hollow. You do not regrind every time the tool needs sharpening. You simply hone. You remove no more steel this way than you do continuously honing a flat bevel, however, honing goes faster because you are not always honing the steel in the center of the bevel between the heel and tip of the bevel.

A similar arguement can be made for Japanese style chisels which have a hollow ground into the face. Or Japanese planes which have several hollows in the sole. However, the important areas (the reference areas if you want to call them that) are all coplaner. The hollow is only in areas not vital to the tools performance, but make a big difference in the amount of time required honing. Hollow grinding a chisel or plane iron is the same. The hollow is in an area not vital to the performance of the tool, but makes honing faster and freehand honing easier.

[Derek Cohen]

To the best of my understanding, a secondary bevel, or a hollow-ground bevel (off of a wheel) makes it very difficult to do bevel-down work, such as flattening the bottom of a hinge mortise, where you "ride the bevel". It seems that a hollow-grind would tend to dive into the wood, and that a secondary bevel would require tilting the blade up off of the primary bevel and onto the miniscule secondary bevel where you have less control.


Hi Wayne

Don't confuse "secondary" with "micro" bevel. In my world a secondary bevel is one that is honed at a higher angle than the primary bevel. A micro bevel, on the other hand, is simply a tiny bevel .... it can also be a secondary bevel if it is honed at a higher angle..

When you hone a blade with a hollow grind you can create either a secondary bevel or a coplanar bevel. A coplanar bevel is formed when you hold the hollow grind flat.

You can use a coplanar hollow ground chisel in the bevel down orientation because it has a bevel face for registration. You will struggle to use a hollow grind with a secondary bevel since the secondary bevel has a small registration area. A microbevel does nor change anything with the coplanar hollow grind. It makes the secondary bevel situation even more difficult.

Clear as mud?

Regards from Perth

Derek

[Frank Drew]

A similar arguement can be made for Japanese style chisels which have a hollow ground into the face. The hollow is only in areas not vital to the tools performance, but make a big difference in the amount of time required honing. Hollow grinding a chisel or plane iron is the same. The hollow is in an area not vital to the performance of the tool, but makes honing faster and freehand honing easier.

Robert,

A quibble, probably, but I'd call the area with the hollow on Japanese chisels and plane blades the back of the blade rather than the face. The hollow on those blades does decrease the time flattening the back, but doesn't directly affect the time spent sharpening (honing) the bevel.

[Robert Rozaieski]

Robert,

A quibble, probably, but I'd call the area with the hollow on Japanese chisels and plane blades the back of the blade rather than the face.

Quibble away :D. Some call it the face, some call it the back. Both terms have been used interchangably for longer than I have been alive (Google "chisel face" to see several references).

At any rate, my main point was that the steel is hollowed to make the process of honing and/or flattening easier by reducing the amount of steel that needs to be honed to only those areas that are critical to the tool's performance. Japanese chisels can still be used to pare bevel up and not be affected by the hollow. Hollow grinding a bevel is the same concept.

[Dan Barr]

i agree that a hollow ground is perfectly acceptable and helps in efficiency of honing. Also, i have no problem doing bevel down work with a hollow ground bevel.

However, a micro bevel is detrimental to that operation and does not belong on a chisel. also, micro bevels encourage poor sharpening techniques and habits.

when the operator goes to hone his now dull micro bevel, he will only lightly touch it up. this works for a little while. then he has to hone the initial bevel down in order to allow the new microbevel the space to exist. (a lot of times, the operator will see no use in honing the initial bevel at all now and will prefer to grind that initial bevel, believing only that the micro bevel performs primary function) touching up a microbevel eventually leads to a higher and higher degree angle of the cutting edge. eventually, no results are seen from sharpening the micro bevel alone. However, if one has spent the time honing properly (with or without a hollow ground bevel) they would find that they would have maintained the proper bevel angle all along or would have saved steel by not grinding as frequently (if that was the case)

i think some apple/orange miscomm is going on here.

Quibble: the flat part of the chisel with no bevel is called the face.

Question: japanese chisels, with the face hollow ground; do they yield bevels with concave/convex cutting blades after the operator hones beyond the flat part? (approximately the first 1/4 inch of the face) hmmm.... if only that little bit of steel is to last that long, then grinding/setting a bevel would be a very infrequent task. i would imagine that honing is all that most operators ever do to some of their chisels.

cheers,

dan

[David Gendron]

Sorry to say that Dan, but do put a micro bevel on all my tools or at least a lot of them, and never have any problem with sharpening what so ever. An other point is that at low angle, like on paring chisels, it keep the edge of the tool a bit stronger, not as prone to nick as easily!! Just my opinion BTW.

[Frank Drew]

Question: japanese chisels, with the face hollow ground; do they yield bevels with concave/convex cutting blades after the operator hones beyond the flat part? (approximately the first 1/4 inch of the face) hmmm.... if only that little bit of steel is to last that long, then grinding/setting a bevel would be a very infrequent task. i would imagine that honing is all that most operators ever do to some of their chisels.

Traditional users of Japanese chisels and plane blades rarely if ever use grinders, perhaps only if the edge has gotten badly nicked. However, every time you sharpen/hone the bevel, you also lap the back (face, if you like) of the blade on the fine stone; that works to keep the hollow where it belongs, away from the cutting edge. In time, though, that little bit of flat between the cutting edge and the hollow will disappear, and the blade needs to be adjusted. The method I've seen is to hammer the bevel, gently, using a special anvil, to flatten a small portion of the hollow, followed by lapping the back(face) on a steel plate with abrasive grit, then polishing lapping.

[Wayne Cannon]

Thanks for sharing your experiences re honing styles for bevel-down chisel work.

I'm comfortable with a hollow grind, finished off with a flat honing of both the bevel's edge and heel, but not just the edge.

Please forgive my treating the terms "secondary bevel" and "micro-bevel" as synonymous. I was referring to the tiny, slightly steeper bevel at the chisel's edge to speed up sharpening by removing less metal (though it catches up with you eventually).

I understand that the micro-bevel should work fine for a plane, or for a chisel used for face-down (back-down) paring, or chopping (e.g., dovetails). It sounds like most of you agree that a micro-bevel hinders the bevel-down use of a chisel if you want to use the beveled surface to control your cut -- much like bevel-rubbing in turning, or like the sole of a plane -- since with a micro-bevel, you would need to tilt the chisel a couple of degrees up off of the bevel face in order to cut horizontally, resulting in only the very small micro-bevel as a control surface rubbing on the wood.

[Mike Henderson]

If you freehand hone your chisels and don't hollow grind them first, you will almost certainly have a bow in your bevel. The human hand just isn't precise enough to hold the chisel perfectly flat while honing.

What happens is that you grind a bit more off the lower part of the bevel and on the upper part of the bevel because you rock the chisel slightly when honing.

Once you get that bow established it's very hard to get rid of by freehand honing because you just can't hold the chisel accurately enough to only hone the middle of the bevel.

So unless you use a honing guide to sharpen your chisels (including honing) you don't have a perfectly flat bevel to work with. This is essentially the same as putting a secondary bevel on the chisel.

But it must not cause much of a problem because our ancestors sharpened all their tools by hand and were able to produce very good work.

Mike

[Added note: I do carving. The way most people, including myself, sharpen gouges guarantees that the bevel will not be flat (will have a bow) and you depend on "riding the bevel" to do good carving. I can't explain how it works but it works.]

[Frank Drew]

Mike,

If I'm in a hurry, I like a jig to help me keep the bevel flat on the stone when sharpening, but the Japanese carpenters I've worked with did all their their sharpening freehand, maintained flat bevels and honed subtle convex edges in their plane blades (positive camber) and ever so slightly concave edges in their chisels (to ensure accuracy when cutting on a line). Additionally, because the steel on those tools is fairly thick, the bevels are pretty wide, so easier to ride without rocking.

However, if anyone thinks they can freehand a secondary bevel just by lifting up the heel of the bevel for a few strokes, they're kidding themselves; as you say, the human hasn't been born who can keep a tiny bevel flat on the stone.

[Pedder Petersen]

In my world a secondary bevel is one that is honed at a higher angle than the primary bevel. A micro bevel, on the other hand, is simply a tiny bevel .... it can also be a secondary bevel if it is honed at a higher angle..



Hi Derek,

I do not understand how to hone a tiny bevel without altering the bevel. Please help me.

Cheers
Pedder

[Derek Cohen]

I do not understand how to hone a tiny bevel without altering the bevel. Please help me.

Hi Pedder

Neither do I! OK, the issue is like this ...

My preference is freehand honing, and I will do this for all BD plane blades and chisels. A simple hollow grind allows this to be done without a secondary bevel.

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Hollowgrindblade1.jpg

Simply use the hollow to balance the bevel face and you can work the microbevel without difficulty.


For BU plane blades I use a honing guide as these planes are set up with high cutting angles, and these involve a secondary bevel. The small secondary bevel is a microbevel.

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/Primary-secondarybevel-flatface1.jpg

Here the secondary and microbevel requires the support of a honing guide.

Regards from Perth

Derek

[Bob Strawn]

For what it is worth, I agree entirely. I use a flat bevel almost exclusively. No secondary, and no micro bevel. I strop regularly as I work, so I might have a slight dubbing. I use quite stiff and hard horse butt to strop with. Still, there is going to be a touch of dubbing anyway.

If a secondary angle is desired to strengthen the steel, unless clearance is needed, you are better off eventually wearing the tool to that final angle. The blade will be stronger as a result.

There are two reasons I might use a secondary or micro bevel. If I need clearance, or if I am changing the bevel of the blade. If I sharpened less often, then a micro bevel might increase the life of my tools.

Micro bevels can, if you wear down your blades before sharpening, be more economical with tool steel. The problem is that it takes quite a bit of attention to detail to not mismanage your micro bevels, and end up using more tool steel up.

Bob

[Pedder Petersen]

Hi Derek,

thank You, now I understand!

Cheers Pedder