Wire or Feather edges, need some help.

[Steel130]

Ok so basically I would like to get some ways to totally identify a wire edge aka a feather edge. I can get edges to wittle hair and cleanlu push cut phone book paper. I know that you can " Feel " for a wire edge with you nail. But what is the proper technic for this? Generally I run my nail perpinducular to the edge bevel. I just want to make sure my edges are true. I strop as well, so I have my basics covered.

 

[Obsessed with Edges]

Try slice/draw cutting the paper, instead of push-cutting. I prefer testing with a slicing/draw cut (heel to tip), because more of the edge will be involved in the cut. A push-cut may only indicate condition of a narrow portion of the edge. Do some slicing cuts in the phone book paper, using the full length of the edge, then make 2 or 3 hard draw cuts into a piece of firm/hard wood (cross-grain), then try the paper again. More often than not, if a wire edge is there, it won't hold up so well to the wood, and the results will be seen when attempting to slice the paper afterwards. The wood will likely fold it over, or perhaps break fragments of the wire away, in which case the paper will either slip over the edge without being cut (rolled wire, or simply dull), or snag on burrs/fragments of the wire. On the other hand, if the edge continues to slice cleanly through the paper without slipping or snagging, then your edge is likely in very good shape.

BTW, the wood cutting can also be helpful in removing some (but not all) burrs & wires, precisely because of the tendency of them to break off in the wood. Do a few draw cuts in the wood, then test cutting the paper, then strop the edge and test the paper-cutting again. When you get to a point where you can go back & forth between the wood-cutting and the paper slicing, with little or no degradation in cutting performance, you're edge is good to go.

 

[HeavyHanded]

A visual inspection is the best method IMHO. Stand under strong overhead lighting with the blade held in front of your eyes edge down. Slowly rotate the edge back and forth watching how the light plays along the apex. You might need to move it around a bit relative to the light source, but you'll see pretty much every defect with the unaided eye. Do this with an 8x or stronger loupe and you'll miss nothing. A wire edge will look like a lighter patch along the apex but visible in the same spot on both sides of the bevel, a burr will look like a sliver of light just off the apex visible on one side. If you get used to using this method every time you're grinding a new bevel you'll soon be able to pick out the smallest of burrs or wire edges - stuff you can't detect with any other method, in some cases not even with a cut test.

My acid test for burrs/wire edges is to lightly backdrag the edge along the corner of a wooden workbench or dowel. Like a stropping motion but at 70 or 80 degrees, very light - no point in folding over a good edge. If nothing turns up after two or three light scrapes there's nothing there to see.

 

[Bill Hoffman]

Stropping on denim cloth will remove the last miserable, itsy-bitsy, teeny-tiny little
burrs on the edge. Those are the ones that will leave a little tiny bit of paper fiber on your
edge when you pull cut through paper. When those burr remnants are gone, your blade should slide
through paper with no resistance.

Hope this is of value to you all,

Bill

 

[fervens]

The easiest way i have found to see if i still have a burr, is to draw the knife across my thumb nail with the edge trailing (light pressure is all that is needed). if there is a burr, you'll feel it scrape your nail, and if you look at the blade, you will see where the burr collected some nail dust. Also, jdavis on youtube figured out a trick using a q-tip. He lightly dragged the q-tip across the blade, and the burr would catch the cotton fibers and pull them out.

 

[Obsessed with Edges]

The easiest way i have found to see if i still have a burr, is to draw the knife across my thumb nail with the edge trailing (light pressure is all that is needed). if there is a burr, you'll feel it scrape your nail, and if you look at the blade, you will see where the burr collected some nail dust. Also, jdavis on youtube figured out a trick using a q-tip. He lightly dragged the q-tip across the blade, and the burr would catch the cotton fibers and pull them out.

I've noticed the same phenomenon when wiping down the edges of my blades with a damp paper towel. The damp paper will cling to the blade, and fibers from it will be left like convenient tiny 'flags' at each and every burr location on the edge. Might as well hang a neon sign, saying 'Here I am!' Very handy.

 

[Steel130]

Thanks for all the great replies guys! I used the light method with a small high powered penlight. Works great. Maimly the thumb nail was giving me good feedback in confirmation with the light.

 

[MadMullet]

I pick up a cheapy 30x jewelers loop from the amazon that I keep in my sharping kit. you can find them under 5 bucks with a bright LED built in to it. they work great for getting a real close up look at you edge.

 

[Steel130]

Ok so my only problem is. I have been using a flashlight to inspect my edge. Sometimes I can see just the faintest little glint back holding the flashlight perpendicular to the edge. Am I just seeing part of my scratch pattern still? Because at this point the edge will easily push cut/pull cut phonebook paper. I just want to make sure I have a "true" edge. Its driving me partly insane. It also does this some even after stropping.

 

[Obsessed with Edges]

Ok so my only problem is. I have been using a flashlight to inspect my edge. Sometimes I can see just the faintest little glint back holding the flashlight perpendicular to the edge. Am I just seeing part of my scratch pattern still? Because at this point the edge will easily push cut/pull cut phonebook paper. I just want to make sure I have a "true" edge. Its driving me partly insane.

The glint of light may or may not be a burr. It could also be a very subtle micro bevel at the edge. A good magnifier used in addition to the bright light will reveal what you're actually seeing. But, bottom line, how the edge cuts is what matters (the bolded portion of your quote above is a clue). If it cuts well (paper slicing, shaving, etc.), and remains durable after cutting in somewhat tougher materials (like wood or cardboard), I'd say you're in good shape. Never rely solely on how the edge looks (especially if viewed only by naked eye), to determine whether it's 'good' or not. Try to correlate how it's cutting with what you actually see at the edge, and you'll begin to recognize what the edge needs for upkeep/touch-up, in relation to the combined feedback of cutting performance and appearance. An example: Assume your edge was slicing paper well, and shaving well, and then suddenly degraded after cutting some cardboard. I'd look at what happens when slicing paper again. If a portion of the edge snags in the paper, I'd then inspect under bright light and look for that 'glint' of light that indicates a rolled edge (just like a burr/wire), or maybe a dent or chip in the edge. If you see this scenario often enough, you'll begin to notice an association between how the edge is cutting, and what you'd expect to see on the edge in relation to that. Conversely, if the edge 'looks' pristine, with no hint whatsoever of any reflected light from the edge, and goes through hair and paper and everything else like a laser beam, you'll begin to associate the appearance of that pristine edge with how you'd expect it to cut.

 

[Steel130]

Thanks! So basically if mu edge is vry sharp, whittles hair. And I go cut some cardboard then com back and test the edge on thin paper, Obviously it wont whittle hair anyway, and if the edge doesn't seem to have degraded, then its more thwn likely good. I want to get a magnifyer but it seems there must b ways to tell without magnification/strong light.

The glint of light may or may not be a burr. It could also be a very subtle micro bevel at the edge. A good magnifier used in addition to the bright light will reveal what you're actually seeing. But, bottom line, how the edge cuts is what matters (the bolded portion of your quote above is a clue). If it cuts well (paper slicing, shaving, etc.), and remains durable after cutting in somewhat tougher materials (like wood or cardboard), I'd say you're in good shape. Never rely solely on how the edge looks (especially if viewed only by naked eye), to determine whether it's 'good' or not. Try to correlate how it's cutting with what you actually see at the edge, and you'll begin to recognize what the edge needs for upkeep/touch-up, in relation to the combined feedback of cutting performance and appearance. An example: Assume your edge was slicing paper well, and shaving well, and then suddenly degraded after cutting some cardboard. I'd look at what happens when slicing paper again. If a portion of the edge snags in the paper, I'd then inspect under bright light and look for that 'glint' of light that indicates a rolled edge (just like a burr/wire), or maybe a dent or chip in the edge. If you see this scenario often enough, you'll begin to notice an association between how the edge is cutting, and what you'd expect to see on the edge in relation to that. Conversely, if the edge 'looks' pristine, with no hint whatsoever of any reflected light from the edge, and goes through hair and paper and everything else like a laser beam, you'll begin to associate the appearance of that pristine edge with how you'd expect it to cut.

 

[Obsessed with Edges]

Thanks! So basically if mu edge is vry sharp, whittles hair. And I go cut some cardboard then com back and test the edge on thin paper, Obviously it wont whittle hair anyway, and if the edge doesn't seem to have degraded, then its more thwn likely good. I want to get a magnifyer but it seems there must b ways to tell without magnification/strong light.

Yeah, I wouldn't fret too much about the hair-whittling going away quickly, so long as the edge remains good with everything else. And the magnifier is a big help, when first trying to learn all this. Once you've kept at it for a while, in using the knife, observing the changes in the edge and then re-sharpening, you'll start to get a better feel for what the edge needs, and won't necessarily have to rely on the magnifier as much. I do think it's a good habit to use it occasionally, just to stay closely in touch with the process, and to help gauge the improvement in your technique.

 

[stoffi]

No burr will whittle hair after having carved a couple of strokes through wood. Knock off the burr on some wood and see what the edge will do. That's a good test for you.

 

[Steel130]

No burr will whittle hair after having carved a couple of strokes through wood. Knock off the burr on some wood and see what the edge will do. That's a good test for you.

Thanks. I tried this with my Elmax mule. It would still whittle hair. And four passes per side on the strop and presto even crisper again.