Micro bevel and honing

Re: Micro bevel and honing

Derek Cohen (in Perth Australia)


>Hi Bob

Here are my thoughts, given while everyone else slumbers away ..

1. My understanding is that honing basically smooths an edge and this will allow the edge to last longer.Honing also smooths the steel some and this helps the chisel slide easier.

I do not consider that edge holding is the reason for smoothing an edge. But a smoother edge will cut more easiily, all other factors held equal. Importantly, especially for smoothing planes, a smoother edge will leave a smoother surface on the wood. The shape of the blade transfers to the wood, and this goes as much for the serrations of a lower honing grit as the bevel shape of a moulding plane. A lower grit may be less of an issue with a jack or scrub plane, although I still hone the to 8000 for ease of planing (however it is not necessary to go this high).

A lower bevel angle plus a smoother edge are the ideal for paring chisels. Mine are beveled at 20 degrees, compared to general bench chisels at 30 degrees. More on this below.

2. A microbevel smooths the edge and reduces the surface area you have to resharpen. Because a microbevel increases the bevel angle close to the edge, it does make the edge slightly more blunt so a micro bevel is a compromise.

A microbevel may be used for different reasons. But before this is discussed, it is relevant to note that the angle of the bevel does not reduce or increase the actual "sharpness". An edge is sharp when two sides meet in one plane. What you are referring to is the degree of penetration. The lower the bevel angle, the greater the ease of penetration (hence the lower bevel angle for paring chisels, which are pushed and never struck). The bevels used for endgrain (such as a low angle jack on a shooting board) or a low angle block plane are honed at 25 degrees (used on a 12 degree bed leaves a cutting angle of 37 degrees). This is contrasted with a high angle smoothing plane (designed for face grain) with a cutting angle of 60 degrees, where the bevel can vary from 30 degrees (on a bevel down plane) to 48/50 degrees (on a bevel up plane).

A microbevel may be chosen to save unnecessary effort in honing. Thus a 1mm wide bevel on a primary bevel (whether flat- or hollow ground) is easier and quicker to hone than the whole bevel. Note that a microbevel is no less a bevel than a primary bevel. Just because it is micro in size does not reduce it effectiveness in cutting.

On some blades a microbevel may indeed be used to strengthen an edge. For example, a mortice chisel may have a primary bevel of 25 degrees to aid in penetration and then a final 30-35 degree edge to increase durability.

3. A blade without a micro bevel would actually be sharper but the edge would not stay as sharp as with a micro bevel.This tradeoff is the reason the micro bevel should be as micro as possible.

I am not so sure that a higher angled edge will remain sharper longer than a lower angled edge. There is interest now in "wear bevels". This is an issue particularly with low (12 degree) angle bevel up planes which use high cutting angles (say a bevel of 38 degrees to reach a cutting angle of 50 degrees). Their edges do not last as long as a York angle (50 degree frog) bevel down plane, using a 30 degree bevel. Hence we shall see move towards dedicated BU smoothers with a 20-25 degree bed (i.e. to reduce the bevel angle). The reason why one does not usually go over 30 degrees on a BD plane is that there is no added benefit since the cutting angle is obtained from the bed/frog (as long as one does not add a backbevel).

Clear as mud.

Regards from Perth

Derek

Re: Micro bevel and honing

Angus Barclay, in New Zealand


>Hello Bob,

there's quite a lot more to micro bevels than what's outlined in your post. I recommend Leonard Lee's book The Complete Guide to Sharpening as an excellent way to learn about micro bevels and a whole lot more sharpening related information.

There's a book review right here at Woodcentral.

You can buy this excellent and practical reference book from Amazon, of course, or if you don't want to spend $15 or so will may find it by clicking on the "find this book" part of these links for a public library near you.

I've borrowed it from my local library a couple of times and have decided that despite my cheapskate tendencies I'll be spending real hard-earned cash soon on a copy I can keep. It strikes me as one of those few books that will be referred to and useful for as long as I continue to work wood.

regards

Angus Barclay

visit Steve Elliot's web site for data on your ?

bill tindall


>http://infillplane.com/

Re: Micro bevel and honing

Warren in Lancaster, Pa


>Often when sharpening a pair scissors we leave the edge a little ragged from a rather coarse stone. The slight serrations catch on the fibers of the fabric and make cutting easier. In wood working a ragged edge catching on fibers will get beat up and bent up hastening dulling. That being said, the considerations Derek mentioned, ease of working and quality of the surface are often more important reasons for wanting a refined edge.

I don't use microbevels, but most people consider the microbevel angle to be the effective cutting angle. For example, no matter what the primary bevel is, if the microbevel is at 32 degrees it gives a similar performance to a flat bevel of 32 degrees.

Exactly...sort of

woodburnbob


>I think your understanding is basically correct.

But I'd edit [out] one phrase, add of few words and delete the last two sentences of the main paragraph...so the statement would read thus:

"My understanding is that honing, if done correctly, basically smooths an edge and this will allow the edge to last longer. Honing also smooths the steel surface some and this helps the chisel slide easier, which admittedly is only a slight and theoretical effect. To wit: this benefit accrues to ants pushing chisels more than to humans. A honed microbevel not only smooths the edge and bevel surface, but also reduces the surface area you have to resharpen. This is a big plus for those with no time to sharpen, those free-handers who can't keep from rounding over their bevels, and those who can never find their sharpening jigs when they need them. Because a microbevel increases the bevel angle close to the edge, in theory, it [does make the edge slightly more blunt] would increase cutting resistence, so a micro bevel is a compromise... but this compromise is negligible, again, unless you're an ant pushing a chisel."

The ideas in your last two sentences don't fully make sense to me and seem to perhaps confuse what's already pretty well stated:

1. "A blade without a micro bevel would actually be sharper but the edge would not stay as sharp as with a micro bevel." (I think, two honed edges with slightly difference cutting angles can be equally "sharp" and durable.)

2. "This tradeoff is the reason the micro bevel should be as micro as possible." (I think, the microbevel argument is exclusively a speed and effort argument about techniques of edge renewal.)

Re: Micro bevel and honing *LINK*

Joel


>I think the real reason for microbevels has been lost.

Here is what I was taught:

1) a micro bevel is a very tiny secondary bevel no more than a few thousands wide at the edge of a blade. Anything more behaves differently.

2) I am pretty sure you are talking about secondary bevels not microbevels and the only purpose of secondary bevels is to strengthen the edge and to save sharpening time. Also with honing guides it is far far easier to add a secondary bevel than it is to match the primary bevel.

3) the lower the angle of a chisel sharpening the easier it is for the blade to penetrate wood. Easier penetration means less force and more control. This is key to great chisel preformance. BUT

4) a low angle is fragile.

5) IF you take a chisel at a low angle and chop with it there is a good change you will turn or chip the edge. Add a secondary bevel and the edge is strengthened BUT because of the wideth of a secondary bevel you just lost a good bit of the penetration. HOWEVER

6) A very tiny secondary bevel, only a few thousands wide - a micro bevel adds the strength to the edge but since it is so small doen't change the angle at which a chip rides up on the bevel. Actually it does but only if the chip is very very thin and small. For normal chopping where we insert the chisel fairly deep and take thick chips true microbevel really improves performance. On bevel down plane irons the effect is minimal if at all.

7) The microbevel is formed by about 4-6 strokes on a very fine stone. This is almost impossible to do with a honing guide and secondary bevels formed with a honing guide are usually very large and lose the effect. When you resharpen you go back to the primary bevel and quickly wipe out the tiny microbevel. This not only keep the microbevel from growing into a secondary bevel - it give a consistent reference for free hand sharpening. So there is a second benifit.

8) the effect of better pentration with a strong edge is best observed using American and European hardwoods. On Soft woods used in Japan the woods are fexible so a high primary bevel with no microbevel works just as well and saves a step.


How to create a microbevel

Re: Micro bevel and honing

Derek Cohen (in Perth Australia)


>Hi Joel

All good points, but ...

7) The microbevel is formed by about 4-6 strokes on a very fine stone. This is almost impossible to do with a honing guide and secondary bevels formed with a honing guide are usually very large and lose the effect.

Can you expand on why you consider it impossible to form a microbevel with a honing guide? The logic escapes me. I am reasonably skilled at honing freehand, but not good enough to create a microbevel that is one clean edge. I am more likely to create a rounded edge since it is dificult to maintain the same honing angle. With a honing guide, such as the Veritas models (with the 1- and 2 degree options), this is a simple matter and, as one does so, less honing is needed. Therefore the microbevel can be as small or as large as one chooses.

Regards from Perth

Derek

Re: Micro bevel and honing

Joel


>A fair question:

the goal of a microbevel is to establish a steep tiny bevel that preserves the lower angle performance of the primary bevel.

if all you can do with a jig is add in 1 or 2 degrees then you don't have much of a performance boost. that is your edge isn't much stronger than it would be with te primary bevel and the penetration is about the same. you need about 5 degrees give or take.

With a microbevel created with 4 or 5 strokes on a fine stone following the instructions in the link in my previous post you will find you can get very very consistent - it just takes a little practice (Get my video if you want more explaination) and as long as you create a tiny wire edge the rounding, if you create it, means nothing (it's only 5 strokes) - you still get the performance enhancment. Incidently in case I wasn't clear the microbevel is formed on an edge that has been already sharpened properly so you don't worry about not getting a consistent edge.

Note: after create the tiny wire edge you have to chase it to get rid of it.

The other problem with jigs is that all the secondary bevelsI have seen don't with jigs are too wide to be considered microbevel - by the time you have set the tool in the jig, and done a few stokes to set it up you are too wide. the LV jig allows you to just move a dial but the amount isn't enough and again there seems to be a tendency to put on too wide a secondary bevel.

Re: Micro bevel and honing

mikew


>Hi Joel--I agree. Even if one uses a jig for the grunt work, a freehand secondary bevel of several strokes is good enough.

Question. You say 5 degrees is needed, and of course the LV jig doesn't go that far. So how do you know you aren't adding only 3 degrees, or 10 degrees when doing so by hand?

Ok. I was being silly. For me, I don't really care. I don't sweat the small stuff. I just wing it, lift the blade by a little. I have no idea what the real angle is--it's just simply more than the primary.

Not that it is made anymore, but the Millers Falls #240 honing guide will allow one to alter the secondary to their hearts desire. Got a couple. Neat guides. Back to the LV guide, a playing card or two on the final secondary swipes will raise it just over 5 degrees. By hand is much easier.

I think the quest for precision in sharpening is a two-edge sword. The good side is that people are more aware of what technically makes for the sharp and or strong edge. A down side is people tend to sweat the precision of the process too much.

Take care, Mike

Re: Micro bevel and honing

Derek Cohen (in Perth Australia)


>if all you can do with a jig is add in 1 or 2 degrees then you don't have much of a performance boost. that is your edge isn't much stronger than it would be with te primary bevel and the penetration is about the same. you need about 5 degrees give or take.

Oh God, Joel, now my head hurts! Or is this the perfect sales pitch so that I get your video?! < grin >

Are we talking about the same thing? The microbevel I use it geared towards being a "shortcut" to the final bevel. When, for example, David Charlesworth demonstrates this on an Eclipse honing guide, he is only changing the bevel angle by 1 or 2 degrees. What you appear to be saying (and it is VERY late at night here and this is my excuse) is that 1 or 2 degrees is insufficient to strengthen the bevel edge. So you are not looking for a change of cutting angle, per se - ?

Kidding aside, I will look out for your video - can you post a link?

Regards from Perth

Derek

A few comments, Joel

woodburnbob


>Thanks for the link, Joel. It reminds me I've never learned the relationship between you and Bob Mathison; I sometimes wonder if you are the same person.

I stopped and read the whole 13 part lesson on Honing and Sharpening. It's jam packed with very good information and advice...one of the best I've read.

But it gave me a weird sense of d�j� vu, until I realized I'd read the whole thing years ago when I entered similar discussions of these topics here or on Badger Pond.

Anyway, your argument for micro bevels here seems to boil down to preserving penetration (by keeping the cutting angle relatively small) while still protecting against edge failure (by keeping the cutting angle relatively large). Makes perfect sense to me.

One thing that's left out is whether one starts with a flat-ground bevel or a hollow-ground bevel. I use a Tormek which produces a very uniform and straight hollow-ground bevel...when I'm careful. I then easily free-hand a hair thin "micro-bevel" simply riding on the heel of the grind...working back-and-forth bevel-to-back using a translucent Arkansas stone I bought from you. But perhaps you wouldn't agree that it's the equivalent of a sort of micro-bevel. I've never actually done the math on the angle formed by a small cord across my grinding wheel.

I was a little surprised with your recommendation for a 5 degree micro-bevel. So I did do the math on that. Taking a chisel 11 inches long, with a 25 degree bevel, that puts the end of the handle butt 4.64 inches high. To add a micro-bevel at 30 degree, the butt needs to be 5.50 inches high. Something tells me you're not raising the butt nearly an inch. But maybe you are. For comparison a 26 degree angle requires the butt to be 4.82 inches.

The final point I'd mention is that none of this matters if one is able to use a skewing or paring motion in using a chisel. Obviously, that's not possible if one is cutting mortises or the like. Here I'm alluding to cutting edge geometry and effective cutting angles, whereby one can have a strong 30 degree bevel and a high penetration 25 degree effective cutting angle.

Re: Micro bevel and honing *LINK*

Joel


>"Are we talking about the same thing?"

No. In my terminaology a microbevel is miniscule. I can barely really see it with the naked eye, I can see it's there because there is a different band of reflection at the cutting edge. DC is using it what I would call a secondary bevel to gurenttee he is honing with a jig at the very edge and to mimimize the amount of work. What I am doing is for different reasons (see earlier posts). His overall angles on a bench chisel are much higher than traditionally quoted.

"Kidding aside, I will look out for your video - can you post a link?"

Link is below. THat's my video. THere are two - one for oilstones by Maurice Fraser, my teacher and the guy who did the pages on the site I posted previously. He doesn't use waterstones just oilstones but the techniques we present are basically the same. I kind of go through it with waterstones but He does a better job. It's an offical Norton video so you should be able to get it from your local norton distributor.


norton sharpening video for waterstones.

Re: A few comments, Joel

Joel


>"One thing that's left out is whether one starts with a flat-ground bevel or a hollow-ground bevel. I use a Tormek which produces a very uniform and straight hollow-ground bevel...when I'm careful. I then easily free-hand a hair thin "micro-bevel" simply riding on the heel of the grind...working back-and-forth bevel-to-back using a translucent Arkansas stone I bought from you. But perhaps you wouldn't agree that it's the equivalent of a sort of micro-bevel."

IT's not - it's too wide - I hollow grind, hone the primary bevel which intially is very very narrow, then put my tiny weeny microbevel on top of that.

"I was a little surprised with your recommendation for a 5 degree micro-bevel. So I did do the math on that. Taking a chisel 11 inches long, with a 25 degree bevel, that puts the end of the handle butt 4.64 inches high. To add a micro-bevel at 30 degree, the butt needs to be 5.50 inches high. Something tells me you're not raising the butt nearly an inch. But maybe you are. For comparison a 26 degree angle requires the butt to be 4.82 inches."

interesting observation. MY chisels are shorter so I am getting a higher angle than or or two degrees but you may be right - I may not be getting the full 5 degrees like I stated. It's an interesting question. but I am consistent and I do get longer edge live with better penetration. I'm also sloppy so I bet I am getting at LEAST 5 degrees. Worth looking into at any rate.

"The final point I'd mention is that none of this matters if one is able to use a skewing or paring motion in using a chisel. "

The overwhelming amount of chisels I do with bench chisels is chiseling the waste away from dovetails or something like that and the chisel is presented square to the work.

Re: Micro bevel and honing

Thom D


>Honing is just more sharpnening. Sharpening is reducing the edge thickness to increase the pressure on the edge when a force is applied.

Mircro bevels are there either to make the process of sharpening proceed faster, or to change the edge geometry. Edge geometry can be messed with for many reasons.

unintentional micro bevel

Adam Cherubini


>You don't THINK you hone micro bevels, Warren but if you hone by hand, you probably do have micro bevels.

I think the smoothness of the wood surface is a red herring. You hone until the tool cuts. Beyond that the tool cuts more easily. Avoiding scratches WILL result in a longer edge life. Scratches should also be longitudinal (don't hone side to side).

Micro bevels are good because they strengthen and more importantly stiffen the edge.

I'm working on an article on this subject and I don't want to type it all here, but I can tell you this: Mr. Lee knows what he's talking about and his little jig thingy and his micro bevels are good science.

Adam

Re: Micro bevel and honing

charles


>If you by-pass the microbevel you'll never have to regrind unless the edge is chipped.

Read Planecraft.

Re: Micro bevel and honing

charles


>Let me add to that any supposed 'time savings' during honings of the microbevel are lost when a regrind is necessary when the micro becomes too large.

Net, there IS NO TIME SAVED by using microbevels.

Keeping an edge cutting sweetly with no microbevel, i.e. honing the whole bevel, still only takes a few swipes. Just set a stone on your bench (in the well) and take a few strokes when you sense the cutting implement needs it. Sharpening is an entry level skill. As I mentioned in another thread, I taught my son to jig and freehand hone when he was about 13. He does a perfectly acceptable job now and did then as well.

Re: unintentional micro bevel

Warren in Lancaster, Pa


>Adam, I agree with you on several of these points. However in the last 25 years, I have sharpened my turning tools, my carving tools, and my smoothing plane for just one reason: to enhance the quality of the surface. These surfaces are all left unsanded. The surface quality is how I judge when these tools need sharpening. I rarely notice difficulty in pushing these tools; ease of working is but a side benefit.

In contrast, the fore plane, roughing gouge, mortise chisels, etc, do not leave a finished surface and are sharpened only to ease their working properties.

Re: Micro bevel and honing - another opinion

Norman (Ottawa, Ont.)


>I'm going to go against the grain here...

I don't hone micro -bevels on my plane irons.

The reason is I grind a primary grind when I need to

and hone the same primary grind on a series of stones

by hand. The bearing surface of the primary ground

part of the iron is sufficient for me to keep

from rocking the iron. This process allows me to

very often and quickly freehand re-hone the iron.

If I were to hone a micro-bevel in , when I need to re-hone,

I would then need to either:

1. Remove the micro-bevel somehow and re-hone the primary bevel

and re-create the micro-bevel.

or

2. Hone another angle of micro-bevel in, as it will

be very difficult to hone by hand the very same

micro -bevel angle ( bearing surface is miniscule).

This introduces facets and rounding of the iron tip

in my opinion.

This system works well for me, and I really like the simplicity of

a single angle on the plane irons for the reasons mentioned above.

Of course , re-honing the exact same micro-bevel angle is entirely possible using sharpening jigs, measuring, etc..

but I find this all detracts me from sharpening as often as I'd like.

I also need to mention that I don't hollow grind, but use the LV abrasive belt system, so the iron tip is flat not hollowed.

I realize there are many good arguments for having a micro-bevel in,

but in my mind it unnecessarily complicates the whole sharpening process and begins to make it tedious, therefore possibly causing myself and maybe others to not hone irons as often as necessary..

Norman

Re: Micro bevel and honing

Chris Scholz


>This is pretty confusing for me.

If strength would be the main reason for a microbevel, would it not be better to hone the whole bevel at the shallower angle? (What strength are we talking about, strength as in resistance agains bending? strength as in resistance against abrasion? or some other kind of strength?)

----

if all you can do with a jig is add in 1 or 2 degrees then you don't have much of a performance boost. that is your edge isn't much stronger than it would be with te primary bevel and the penetration is about the same. you need about 5 degrees give or take.

Re: Micro bevel and honing

Joel


>Now I'm confused.

"If strength would be the main reason for a microbevel, would it not be better to hone the whole bevel at the shallower angle? (What strength are we talking about, strength as in resistance agains bending? strength as in resistance against abrasion? or some other kind of strength?)"

I talk about two things.

1) STrength of the edge. the higher the bevel angle of the chisel the more strength the edge of the chisel has to resist chipping and metal fatigue (bending).

2) PEnetration angle. The LOWER the bevel angle of the chisel the less force it takes to drive the chisel into the wood, which means I have more control and the less lateral force is exerted by the chisel bevel to split the wood. Again this means I get more control.

THe problem is both objectives are mutually exclusive. However with a tiny secondary bevel, a microbevel, you get a lot more strength in the chisel edge with almost no change in penetration force.

THe trick is getting a small enough microbevel, one that is so small a shaving, will ride over the microbevel and not be deflected at a higher angle. 5 strokes on a 8k or arkansas stone (pick your method) is all you want. THen chase the new burr formed. Look to my earlier posts for instructions.

Now some folks may not agree. All I say is test the practice. Not with a mongo big secondary bevel, but a tiny one as described. See if it works for you. I was trained to do this and then fell out of the habit. Then after about 10 years as a single bevel sharpener I saw the light and went back to my training. It makes a difference.