Sharpening - dealing with the wire edge.

[Frederick Skelly]

I have been experimenting with my Aldi's at 22* for several months now, and use them for paring. So far, so good.

To remove the wire edge, I work the back as others suggest. Then I use a trick that I think I got from one of Charles Hayward's articles..... I make 1-2 passes down the length of the bevel, on the corner of a softwood block - like a knife slice, pendicular to the corner. It works for me, anyway.

Fred

[Rob Luter]

Oh, so you're saying your plane iron was made of A2? :-)

Sorry, I couldn't resist. Terms like "large ... grain structure" are of course relative.

IIRC Aldi advertises their steel as Cr-V, which can refer to an extremely wide range of alloys. Some of them take very refined edges, others are veritable chip-fests.

Nope. My A2 stuff sharpens great. This was some form of tool steel I wasn't familiar with (and I used to be a tool and die designer). As I recall it was group M Molybdenum high speed steel.

[ernest dubois]

I wouldn't rely on stroping to remove the burr, here is why. The pressure exerted against the flexible surface is going prematurely cause the burr to break off and leave a serrated edge. For an edge as smooth as possible the burr needs to release of its own accord by being honed off against a flat inflexible surface.p6270569.jpgp6270572.jpgp6270573.jpg So, the quality of the sharpened edge is directly related to the grit of the last stone used to release the burr.

[Andrew Hughes]

You could try jointing the edge it will be stronger edge. Hold the chisel vertically on you finest grit stone and pop that wire off. If it's one long piece you will know that there's no defects in the edge.
You will need to go back to your finest stone in the same manner as before. The new wire should be very small and easily removed.

[Robert Hazelwood]

The advice so far seems good to me. I will add my own method: After I've finished polishing the bevel, on the finish stone I alternate back and bevel strokes, very light pressure with the bevel moving forwards. Perhaps 5-10 strokes; this seems to remove the burr effectively. The typical advice I've heard for woodworking tools is to remove the burr by just working the back on the finish stone. In my opinion that is not quite enough- it tends to just push the burr over to the bevel side. So you have to alternate working from each side, and with each iteration the burr gets smaller/weaker and is eventually gone. I follow up with a bare leather strop to remove any burr remnants....but the edge is almost always good right off of the finish stone. Alternating sides is easier to do while freehand sharpening, but can be awkward with jigs or machines.

I also agree with the other posters who did not like the idea of the diamond hone as a finishing stone for the back. I think you can still get a good enough edge with it (once you manage the burr issue) but they are very harsh for a finish stone in my opinion. If you don't have anything else to use (like a fine oilstone or waterstone, or something like a spyderco UF ceramic) then I would try very fine sandpaper or micromesh (on a flat surface)

[Derek Cohen]

Some steels, such as A2, are more reluctant to "let go" the wire. I think that it is important that one does not let the wire become large, as then it becomes more difficult to remove.

Years ago I would recommend removing the wire between stones, by flipping the blade and working the back as well. Today I feel for the wire and move on to the next stone as soon as it is present (I can feel a wire - or see it - at 13K). I suspect that some work the bevel with the lowest grit (e.g. 1000) more than they need to do, possibly to ensure that they have hones across the bevel face. A fine wire is enough - the bevel will not improve with a larger wire.

I expect that the wire to diminish in size as the stone becomes a progressively higher grit. By the highest grit the wire should be fragile and fall off. If it does not, then be prepared to work the wire back-and-forth on the highest grit until it has worn down and falls off. It must not be forced off (such as dragging the blade through end grain) as this will tear the wire and leave behind a serrated edge.

Regards from Perth

Derek

[Andrew Pitonyak]

Where do you live John? Perhaps you can duplicate the problem with someone from the creek present..... If you live in Ohio, you can swing by my place....

[John C Cox]

It would be a bit of a hike from South Carolina... .

I used to be a member in the Greenville Woodworker's Guild when I lived up that way.. Unfortunately they don't have anything like it down state.

The guys I have met down here hardly even use chisels and hand planes... If it can't be done with a table saw, drill press, or power nailer - they don't do it..

[Stanley Covington]

Pete has it right: Either the bevel angle is too low, or the steel has problems. Or... there might be other factors to consider.

I think many people do not understand just what a “wire” is.

Think about it. Draw yourself a cross sectional diagram of a chisel or plane blade with a "wire." Ask yourself “How does this thing develop?" "What happens when it breaks off?" Does it make my blade cut better?" "My job easier or more enjoyable?" Really think it through.

A “wire” is just a big honking burr: A long, thin flag of steel projecting from the cutting edge and curving out into space. They most often develop when the angle of the blade as it is sharpened on the stone is less than the angle of the blade's existing bevel. Draw these lines on your little diagram and you will see what I mean. Pressure of the blade on the stone causes the steel at the extreme cutting edge to thin, project outward, and bend, even if it is relatively thick.

Repeatedly bending this "wire" from one side of the blade to the other causes its root to work harden, become brittle, and break/ tear off. Work hardening results even if the steel does not heat up, you know. Imagine what the cutting edge looks like after this "wire" breaks off at its root. Not pretty. This damage can be fixed, but why waste the time, effort, steel, and sharpening stones? Best to avoid the whole bloody mess altogether.

When working a blade hard on rough stones to waste a lot of steel, such as when removing a chipped edge, creating a large burr is unavoidable, but it is pointless otherwise. Unless you are intentionally wasting a lot of steel, the burr that develops when using your roughest stone in the process should be invisible to the naked eye, and barely detectable when you drag your fingerprint ridges over it. This is the objective when using your first stone in a normal sharpening session. 1000 grit is where I start for normal sharpening.

Going back to the point I touched on above, it may also be helpful to consider why the bevel angle created during one sharpening session might become less than that made during a previous session, and how to avoid this tendency. Over repeated sharpening sessions, nearly everyone tends to gradually lay the blade down reducing the bevel angle. It simply feels more stable to do so. And at lower angles, the blade seems to cut even better,... until it fails, that is. Be sure to use a gauge of some sort to check your bevel angles when sharpening to confirm you are maintaining an adequate angle. When in doubt, 30 degrees is a good place to start.

Besides regularly checking your blade's bevel angles with a gauge, there are other things you can do to maintain the angle that works best for your tool and the wood you need to cut. First, pay attention and keep the blade’s entire bevel in contact with the stone when sharpening. It serves as a jig. This is more than a little difficult to do if your blades have double bevels or rounded bevels .

Second, and most importantly, at the same time focus your efforts like a laser on keeping the blade’s extreme edge in contact with the stone. Use a marking pen to color the bevel so you can see where it is actually in contact with the stones. You may be surprised with what this reveals. Train your hand to sense when the extreme cutting edge is being abraded.

If you do this properly, a small, barely detectable burr (see "the objective" above) will develop on the rougher stones (e.g. 1000 grit), but will be cut down to nothing on the next stone without work hardening, breaking off, and creating a ragged, jagged edge that needs further repair.

Remember that your rougher stone must do more than just grind away damage at the cutting edge. It must also maintain the bevel angle that best suits the blade and the wood to be cut. In addition, it must also true and flatten the entire bevel, making the sharpening process quicker and surer. If you use your rough sharpening stones well, the rest of the process will be quicker and easier, and your blades will be sharper. I promise.

You can use a kanaban, or other lapping plate, with carborundum grit (or diamond paste, if you can afford it) to true and flatten the bevel. I was reminded of this technique last week by Mr. Nakano, a plane blacksmith, over crackers and tea in his living room. This is the surest and quickest way to achieve the ideal bevel. Hard to argue with 70 years of daily hands-on blade-making experience, and feedback from thousands of customers.

If you are doing all this right and your edge still develops a “wire,” it is very likely the blade’s steel is too soft at the cutting edge, and is being deflected and deformed into a “wire” instead of staying in place and being abraded away to nothing. Perhaps the blade was locally overheated on a grinder and lost its temper, or perhaps the manufacturer intentionally made it soft for his convenience. Maybe he just didn't pay attention. They look good on the website, after all. Such blades have their uses, I suppose, but do not make good woodworking tools IMO. Quality talks and posers walk.

[lowell holmes]

I say stropping cures a lot of ills when sharpening. Try it, if it does not work, do something else.

[Jim Koepke]

Even if my blade has a chip, the burr is worked off as soon as it is noticed. It may be a few removals of burr (wire) before the chip is gone. As Stanley mentions, a big burr is a big mess waiting to happen.

jtk

[Stewie Simpson]

Unless you are intentionally wasting a lot of steel, the burr you first develop on your roughest stone in the process should be invisible to the naked eye, and barely detectable when you drag your fingerprint ridges over it. 1000 grit is where I start for normal sharpening.

(politely) disagree with that comment.

[Derek Cohen]

Stewie, I think that Stanley is saying the same thing as I did, that is, there is no need to create a wire that is any larger than tiny - a larger wire is not a "better" wire. One can feel (with a finger tip) very tiny changes in a surface ... far smaller than one can see. I have no difficulty is detecting an 8000 grit wire with my fingers. If you can feel it, it is large enough.

Regards from Cape Town

Derek

[Stanley Covington]

Stewie, I think that Stanley is saying the same thing as I did, that is, there is no need to create a wire that is any larger than tiny - a larger wire is not a "better" wire. One can feel (with a finger tip) very tiny changes in a surface ... far smaller than one can see. I have no difficulty is detecting an 8000 grit wire with my fingers. If you can feel it, it is large enough.

Regards from Cape Town

Derek

Thanks for clarifying, Derek.

BTW, what are you doing in Cape Town? Can Perth survive your absence

[Derek Cohen]

Hi Stanley

Cape Town? My annual visit to parents, who live here ... well, my mum now. Dad passed away 3 years ago (nearly 101). I've been doing the trip from Oz for 35 years now. Post-Christmas is a quiet time in my practice as it is the long school vacation (I specialise in the child area), and so the best time to be away. We - Lynndy and I - usually use it as the first leg to "somewhere else". Last year it was the UK. This year? ... in a few more days we fly home ... and then I get a couple of weeks in the workshop!

Regards from Cape Town

Derek