Micro bevels as a method to deburr.

Thinking out loud here. If you go to remove the burr from one side of the stone with light pressure edge leading, is the burr stopping the apex of the edge from touching the stone at first? And if so, wouldn't this mean that, with light pressure and a quick enough stroke, that the apex may not come in contact with the stone? Leaving just the burr to be abraded or deformed.

On the other hand, with moderate pressure, you could flip, bend or break the burr as soon as you put the edge on the stone?

And what happens if you were to press the burr against the stone with increasing pressure? No grinding motion involved but still at the desired angle?

Food for thought till i have free time.
 
IMO,

The debate of both sides (flip vs recreate a new one) is only meaningful depends on the level of magnification (how big the burr is and how it's detected). This is the same as previous debate on microbevel, wheter it's called micro bevel as technique or result. It depends on the level of magnification.

I believe with the enough pressure to let the abrasive works on the burr but not enough to re-create is the best way. It seems everyone tries to achieve this, but as human, we can't be 100% sure. What we can achieve is the closest we can get.
Pressure: If it's slightly less, a miniscule of burr will remain, yet might not be meaningful in normal use. If it's slightly more, a new burr might be recreated on the other side. If just right, then it is gone.
Abrasive property: if not enough, more pressure is needed, so it tends to flip the burr, and create a new one. It's where the combination of steel property and abrasive property is important. When talking about steel property, geometry (apex angle), hardness, and material composition that determine ductility all plays a part.
The direction towards which pressure is applied will also determine the formation, naturally. Edge leading should be having less chance of creating a burr, if the combination of pressure, steel property and abrasive is right.
In any case, the perfect apex will get damaged anyway with first use, so it's only a matter of the degree of microscopic change still acceptable.

I came to this after reading the masters comment here and comparing to my experience (mostly cheaper steel such as 440A, 8Cr13MoV) with abrasive that I have (DMT, one natural stone - locally produced, sandpaper, balance strop, cardboard, paper on washboard, Autosol, MAAS polish).

Phewh, I sound like I know a lot, while in fact only offering an opinion. :p
 
Chris "Anagarika";12454256 said:
IMO,

The debate of both sides (flip vs recreate a new one) is only meaningful depends on the level of magnification (how big the burr is and how it's detected). This is the same as previous debate on microbevel, wheter it's called micro bevel as technique or result. It depends on the level of magnification.

I believe with the enough pressure to let the abrasive works on the burr but not enough to re-create is the best way. It seems everyone tries to achieve this, but as human, we can't be 100% sure. What we can achieve is the closest we can get.
Pressure: If it's slightly less, a miniscule of burr will remain, yet might not be meaningful in normal use. If it's slightly more, a new burr might be recreated on the other side. If just right, then it is gone.
Abrasive property: if not enough, more pressure is needed, so it tends to flip the burr, and create a new one. It's where the combination of steel property and abrasive property is important. When talking about steel property, geometry (apex angle), hardness, and material composition that determine ductility all plays a part.
The direction towards which pressure is applied will also determine the formation, naturally. Edge leading should be having less chance of creating a burr, if the combination of pressure, steel property and abrasive is right.
In any case, the perfect apex will get damaged anyway with first use, so it's only a matter of the degree of microscopic change still acceptable.

I came to this after reading the masters comment here and comparing to my experience (mostly cheaper steel such as 440A, 8Cr13MoV) with abrasive that I have (DMT, one natural stone - locally produced, sandpaper, balance strop, cardboard, paper on washboard, Autosol, MAAS polish).

Phewh, I sound like I know a lot, while in fact only offering an opinion. :p
Click to expand...

Good post, Chris. I think that sums it up nicely. :thumbup:

The part I bolded above is how I tend to view these things. The cutting performance, after all of the honing, microbevelling and deburring, is the only thing that really matters in the end. And so much of that is entirely up to the individual, with their own techniques, abilities and preferences. It's a situationally-dependent solution each time, almost without exception. There's no such thing as a truly universal 'fix' for these things, nor is there only one method that's 'correct', while all else is 'wrong'. The ability to recognize what each situation really needs for a 'fix' is what's most valuable. I generally view 'burrs' or 'wire edges' in the same sense, in that both are just bits of weakened steel that get in the way of a well-executed cutting edge. Get rid of 'em, by whatever means seems to work. All of the theorizing about how they're formed or best-removed is sort of moot to me, as there are way too many variables at play, as you've aptly described.

Once again, thanks. :)


David
 
David,

It's you, HeavyHanded, Knifenut1013, bluntcut, unit, Stithawl and many others that share the knowledge, insight, theory and by some, test material that the thanks is due.

I merely made the statement for the benefit of my learning & understanding :o
 
I have held my comments from this thread because it got off track from the question asked. Sure, a burr can be flipped by pressure on a stone without moving or using a hard surface such as wood or glass but the original question was based on grinding action and burr creation which is a singular subject. Currently the subject has broadened and is no longer concentrating on just one factor but many.
 
I'd like to apologize if my tone had become dismissive or come off as a know-it-all. We are all here for the same reason to learn and share what we know about a subject we all enjoy.

HH
 
I would like the OP to way in on this derailment. I find these types of threads tend to gather the best information. I think you guys did initially help him with his original question, but then it started to veer a little. While censorship is good, over censorship can sterilize growth. I think you (knifenut) and heavyhanded and everyone except me really, were making very valid points with your debates and i would hate to see that stop.

To the op's original question. I like using a microbevel to deburr. Especially when it's in between uses and i want to get back to work. I have taken to going from a moderate pressured scrubbing technique for initial grinding to two or four very light pressure microbevel strokes to knock off the burr. Then back to the desired angle with alternating, light pressure strokes. This helps me know i removed the burr and keep the angle i want. As for forming burrs on microbevels, yes i have done this before, but they are considerably smaller than a burr i would form with the same amount of pressure at the normal angle. I think it has to do with how small of a cross section is being ground. Even though that smaller cross section means, that even though you are using the same amount of pressure, the pressure the edge is seeing is increased.
 
fervens,

Your previous post on food for thoughts is interesting. Haven't chance testing this theory yet (pressing the burr, no motion, etc.), also about the apex not hitting the stone/abrasive due to burr standing proud. I guess it's possible given the right pressure and abrasive property.
 
Sorry to drag up this old thread but I'm fairly new here and this has been one of the most interesting and informative threads I have read on here, bearing in mind the importance of burr management to achieve a sharp edge. Much respect to the highly knowledgeable people on this great site.

Keeping in mind the opinions of those who say that deburring/micro-bevelling with the same coarse stone used to form the burr is simply flipping the burr over, surely this leads to weak edge retention?

The question I have therefore: has this been your experience? After raising the angle to debur and maybe some stropping have you found the edge to have poor retention (in comparison to gradual deburring through the grits?)
 
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Nottingham Forest said:
Sorry to drag up this old thread but I'm fairly new here and this has been one of the most interesting and informative threads I have read on here, bearing in mind the importance of burr management to achieve a sharp edge. Much respect to the highly knowledgeable people on this great site.

Keeping in mind the opinions of those who say that deburring/micro-bevelling with the same coarse stone used to form the burr is simply flipping the burr over, surely this leads to weak edge retention?

The question I have therefore: has this been your experience? After raising the angle to debur and maybe some stropping have you found the edge to have poor retention (in comparison to gradual deburring through the grits?)
Click to expand...

No, not as long as the edge is used according to the geometry and finish. Eg rougher edge for drawing cuts, polished edge for pressure cuts.

While micobeveling a rougher edge with a polishing stone will leave it with some irregularities, it still will bias it toward pressure cutting compared to the same edge left with a rough finish or microbeveled on a rough stone.

The key is to eliminate the burr with the fewest number of flips, whether single bevel or microbevel.
 
Nottingham Forest said:
This seems like the key here, but probably easier said than done for an un-seasoned sharpener :)
Click to expand...

Absolutely!
But not as tough as you might think. If you can raise a fairly even burr, just elevate the spine a handful of degrees and make some light leading passes. This is the important part - check every swipe to measure your progress.

A burr of any real size can be felt grinding the fingers across the side of the edge - spine to edge. Even if there is no obvious sensation of a burr standing up, you can do the same thing to the other side and compare - if one side feels "catchier" than the other you don't even need to look.

The intent is to not flip it and to not create a new one inadvertently. What is most likely to happen, you flip it and continue on not realizing for a few extra passes. Whatever reduction you managed has been replaced and the burr tossed over, and maybe not even along the entire edge. Pay attention to how it feels when you elevate the spine, there will be a dragging sensation - if its quiet you'll hear a higher pitch. Once these fade you also know you're close. The take-away is to check often, don't rely on "X number of passes per side" or any other method that doesn't include stopping often to actually verify what's going on somehow.

In any event, you may have stood the burr up or it might be so greatly reduced its time for an even lighter pass or maybe you're done except for some final clean up in specific spots along the edge.

Even if opting to finish with a microbevel, at this stage you should go back to your original angle and make a few light swipes per side, still checking with fingers and visually if anything seems amiss.

Then you can do a final microbevel, run the scratch pattern at a different angle, strop, move on to a finer stone etc.
 
HeavyHanded said:
Pay attention to how it feels when you elevate the spine, there will be a dragging sensation - if its quiet you'll hear a higher pitch. Once these fade you also know you're close. The take-away is to check often, don't rely on "X number of passes per side" or any other method that doesn't include stopping often to actually verify what's going on somehow.
Click to expand...

Extremely useful technique specifics, thank you for sharing your knowledge.

HeavyHanded said:
In any event, you may have stood the burr up or it might be so greatly reduced its time for an even lighter pass or maybe you're done except for some final clean up in specific spots along the edge.
Click to expand...

I have a concern about a burr which has been flipped to stand up, surely the edge formed from such a burr is very weak?
 
Nottingham Forest said:
Extremely useful technique specifics, thank you for sharing your knowledge.



I have a concern about a burr which has been flipped to stand up, surely the edge formed from such a burr is very weak?
Click to expand...

Yes, very weak but also visible. Once you can ID burrs reliably, a wire edge stands out as it presents from both sides - a clean edge does not look the same at all.
 
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