OVERHONING confusing

I did open new thread because of early thread.
after reading that thread i have couple question.

I need to understand why some of you calling 1k level overhoning?
I do understand you can overhone 1k level but when you move to next level that overhoning on 1 k level will go away automatically?
it just doesn't make sense to me?
i thought we call overhoning only in last stage of honing process?
in higher grit level which after that we don't use anything else?
Lastly in last stage you will not get overhone edge by putting pressure?
any input welcome.

Quote:

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Originally Posted by hi_bud_gl

I need to understand why some of you calling 1k level overhoning?
I do understand you can overhone 1k level but when you move to next level that overhoning on 1 k level will go away automatically?
it just doesn't make sense to me?
i thought we call overhoning only in last stage of honing process?
in higher grit level which after that we don't use anything else?
Lastly in last stage you will not get overhone edge by putting pressure?
any input welcome.

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Overhoning is simply a way of referring to the process of honing so much that the edge develops an unacceptably large burr. Obviously you can raise a large burr on the 1k hone, but you don't care because your next hone will knock it off. But as you move up the progression of hones eventually you will start to care about the burr. You can minimise the problem by using pyramids, or by occasionally backhoning on either a stone or pasted strop, or by using a stone that isn't prone to producing a burr, like waterstone with a slurry. You can get overhoning even if you don't use pressure, since burr formation is inherent to honing. Using less pressure gives you a longer period between the point where the edge is properly honed, and the point where it becomes overhoned, which gives you more time to notice that the edge is finished, for example if you're stopping to check the edge every 5 laps.

Overhoning only matters when it affects the final edge. If it occurs on the last hone then obviously it will affect the final edge, but theoretically you could overhone on the 8k stage and then do an insufficient job on the pasted strops or whatever your favorite finishing hone is, and allow this overhoned edge to persist. I'm not sure if it's correct to call it overhoning even on the lower grit hones, but it's the same process and same result that occurs on the finest hone, so I'm not sure why this process should have a different name on the coarser stones than it does on the finest one.

Some knife honers will overhone at each step, using their fingers or thumbnails to detect the burr when it forms, which tells them when to move to the next hone. When they get to their last hone the burr tells them when it's "sharp" and time to stop. That honing process leaves a pretty good level of sharpness for a knife, but not for a razor, even if we could feel the burr with our fingers.

I'd like to understand how burrs form when doing edge leading strokes. I'm not grasping that concept yet. If the edge is going forward on the stones, and the metal is being cut away, what process is acting on the edge to produce a burr? Thanks

Quote:

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Originally Posted by richmondesi

I'd like to understand how burrs form when doing edge leading strokes. I'm not grasping that concept yet. If the edge is going forward on the stones, and the metal is being cut away, what process is acting on the edge to produce a burr? Thanks

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I don't know for sure, but I think it's caused by a combination of plastic flow, plus the material just above where the abrasive grains are cutting that winds up being thin enough that it can curl away from the abrasives. Even when you flip the blade over, it curls back the other way and still avoids being removed. Switching abrasives (by switching from 4k to 8k or vice versa) helps remove it by subjecting it to different conditions than allowed it to form in the first place. Whatever the physical explanation, nonetheless the burr does form, you can see it with the naked eye on a coarser edge like a knife or axe or machete.

Verhoeven discusses burrs quite extensively in his paper on knife sharpening, covering various abrasive grits as well as forward vs backwards honing, as well as backhoning on pasted and unpasted strops, examining the blades . Backhoning produces much worse burrs, and also tends to damage the edge (he hypothesizes that this is because backhoning encourages the swarf to go under the blade rather than over it, and it damages the delicate edge when it comes out). Backhoning on a pasted strop removes the burr pretty completely, while he was unable to demonstrate any effect whatsoever on the burr from stropping on an unpasted leather strop (this particular finding has caused no small amount of controversy on this forum, for obvious reasons).

Please do not start the whole over honing thing again....

Anyone who even thinks they are over honing just take a razor and try and do it...

Every single time these threads start, we get a whole new rash of the infamous "My razor doesn't shave" answered with the equally infamous "It must be overhoned"

Here are the numbers I have

I have honed getting close to 4000 razors now, most from other people of course.... I HAVE NEVER had a razor come to me for an edge that was over honed not one, ever...

I have over honed one razor and I did it intentionally to yank a heel into line...
Th formation of a burr is not the only indicator of overhoning, you can go so far as to get the "fin" so thin that is starts to degrade and the edge fails from high grit laps with pressure or from the same with pastes, but it takes pressure....I figured all this out by trying it...

Again, I say this if you want to learn about how hard it is to overhone a razor, and how easy it is to fix then do it on purpose, take a razor a try it, quit talking about it, and get the stones out and do it...

Sorry for the rant :rant: but IME the whole over honing thing is just a cover for poor bevel sets in the first place...

I've only ever overhoned a razor twice. On a N4/8k, coincidentally. Both times I detected this when I tried to use it; first time I pulled a thin piece of wire out of my cheek, the second time it skipped right over the whiskers without doing anything, and after a quick examination under a microscope a few laps on chrome oxide fixed it. But it's much rarer than underhoning, and especially nowadays I would tell guys to just not worry about it much except that every now and then somebody turns up who's spent the last eight hours on his 1k hone trying to get it sharp, where a little attention to the burr would have saved him considerable amount of time and frustration.

The only times I've overhoned (created a wire edge or burr) is when I had to remove a chip from a razor and honed back and forth with a lot of pressure, just to speed up the process of removing metal.

Getting rid of the burr was way less trouble than keeping light to no pressure for hours and hours on end.

If the bevels are halfway decent and you keep light to no pressure, it is very hard to overhone.

Glen, when you say you've honed close to 4k razors, what exactly does that mean by that?
:)


seriously though, good thread, thanks for the insight.

I think pressure is one of the key factors in raising a burr on a straight's edge, to much and your asking for trouble, how/so/ever, according to Dr.Moss, the respected Canandian shaver, if a burr is encountered gliding a wooden match allong the edge should take care of it once and for all.
I suppose that can be put in the 'for whats it's worth' catagory.
Carry on Gents.

tinkersd of SRP.