Sharpening causes steel to fold over.

[David Vanvorst]

I have been using hand tools for a few years, but I am still a beginner at sharpening.

I got by for a few years using diamond stones, stopping with the extra fine stone (.9 micron, around 1200 grit). A few months ago I got a variable speed bench grinder and a Norton 4000/8000 combination waterstone. I took a lot of time to flatten and polish the backs of my blades, used the grinder to remove some chips, and polished the blades to a beautiful shine on the 8000 stone.

Now, I am having trouble with my blades. After sharpening, they work great for a short while, then the steel folds over. It is a significant fold, much larger than my scraper burrs. It is a very ugly fold that is not even. On a hand plane, the plane just stops working. The fold does not happen suddenly, it usually grows over a dozen or more strokes.

This even happens on my LN blades and Ashley Isles chisel, so I don't think it is the quality of the steel. I never put the Ashley Isles chisel on the grinder, so it must be my technique on the stones (or the stones themselves).

I've tried using the cheap honing jig and the Veritas MK II jig. I've tried following the Norton instructions of never bothering to remove the wire edge (sufficient polishing at 8000 is supposed to remove the wire edge), I've tried flipping the blade back and forth polishing the bevel and back, and I've tried Charlesworth's ruler trick on the back.

I've had the best luck when I make only a single very light pass on the back of the blade with the ruler trick. The best solution has been to sharpen, and when the steel just starts to fold, I make a few light passes on the 8000 stone to remove the fold, but it is difficult to get a clean edge this way.

After spending hours flattening the backs of my blades, I am loath to scratch them up, so I usually only use the 8000 stone on the backs.

What could be causing my problem?

Thanks,
-David

[george wilson]

You don't mention how thin a bevel you are putting on your tools. It sounds like you are grinding them to too acute an angle if good quality blades like LN and the other are folding over.

There is endless discussion here about sharpening,and angles to use.

[Tri Hoang]

It could likely be that the fold is the wire edge that you have not removed. 8000 grit stone will leave a wire edge under normal sharpening pressure. The pressure at the edge of the blade is an important factor to consider, especially if you utilize the micro bevel feature on the MK II.

If you have not done so, I suggest looking at the finished edge under magnification to verify that you actually removed the wire edge.

[David Vanvorst]

I was putting 25 degrees on my LN low angle block plane. A few days ago, I resharpened this one 4 times in one afternoon before giving up. I used a microbevel, so it would have been more like 26.

For the Ashley Isles chisel, I kept the primary bevel that came with the chisel when I bought it.

I had 30 degrees or higher on my bench planes. I don't think I had as much trouble with them. Sometimes the blades are fine, and sometimes they fold.

[David Vanvorst]

Do you mean that if I push down too hard on the 8000 stone, I will get a larger wire edge?

[Tri Hoang]

Do you mean that if I push down too hard on the 8000 stone, I will get a larger wire edge?

Yes...when you use micro bevel with a jig, the sharpening pressure is applied to a very small area at the tip of the blade. One usually needs to use very light pressure in those cases.

[David Vanvorst]

Thanks, I did not know that. Hopefully I will have some shop time this weekend to try this out.

[Andrew Pitonyak]

Thanks, I did not know that. Hopefully I will have some shop time this weekend to try this out.
Be certain to post your results.... Please....

[Jim Koepke]

Thanks, I did not know that. Hopefully I will have some shop time this weekend to try this out.

David,

Welcome to the Cave by the Creek. You do not list your location in your profile. There may be a member who lives close by willing to offer help on a one to one basis.

Please do come back and let us know how things go.

One of my chisels seems to fold a little more than the others. It has seemed to get better with a few sharpenings. It may have gotten too hot while being sharpened previous to my owning it. This one was bought off ebay so there is really no way to know what happen to it before it became mine.

jim

[Stanley Covington]

David:

Can't blame the steel or the stone. I believe the problem is the natural tendency of careful people to unconsciously lay back the angle during sharpening, so that the angle gets minutely, almost immeasurably shallower, and instead of each stroke making the wire/burr gradually thinner until it is abraded away entirely, the wire maintains its thickness and strength, flopping back and forth in the breeze. :o

To fix this, I suggest that, when you get a good thin wire, switch to your finest stone and focus on working the extreme edge of the blade and making the wire thinner with each stroke, but without increasing force. Also, keeping the stone well lubed helps to make the wire better behaved.

Cheers

[David Vanvorst]

In case anyone stumbles across this thread in the future, I thought I would give an update.

I never really solved the problem, but I learned how to work around it.

At a Lie-Nielsen weekend workshop last summer, I replaced my chisels with a set of their O1 chisels. I think the metal in the Sorbys and Ashley Isles chisels wasn't as good.

I think the biggest difference was when I added stropping to my sharpening. I know that the 8000 grit water stone can sharpen as well as most any strop, but I needed it. I got some .5 micron compound with horse-butt leather, and it seems to have fixed my problem. If there was any wire left after the sones, the strop removes it. I don't have the leather attached to any backing, and I use the fuzzy side of the leather. Scientifically, I know this rounds over the edge, but I think of it as a micro-bevel. It cuts as well as any edge I've used. Maybe I will try attaching the leather to a backing some day.

The best part of the strop, is that I leave it on my bench and will strop multiple times throughout the day. Water stones are a pain, and I would avoid sharpening longer than necessary. With the strop, I can keep the edge sharp before it gets dull. It seems to work well on A2 and O1 steel. In an effort to make sharpening more convenient, I recently got some oil stones. With these, I am more likely to keep an edge sharp. I will keep the water stones and grinder for times when I really need them, because I know I will go back to them when I need to take of some metal.

With the strop, I don't have to worry about re-oiling a chisel, so I can make a few passes over the strop quite frequently without slowing down my work.

Adam Cherubini's recent articles in Popular Woodworking helped me stop worrying about having the perfectly engineered edge.

There are many different sharpening methods that work, but I think I finally found the one that works for me.

-David

[Jeff L Miller]

David

You mention a vs bench grinder in your opening post. I've read (and learned) that its very important not to turn the steel blue while grinding, you remove the temper and the hardness of the steel which could contribute to your issue. I quench my tools inn cool water frequently during sharpening on the grinder to avoid getting the steel too hot. There are those that argue against quenching; something about micro fractures in the steel due to the rapid temp change. I'm not a metal smith, only some guy in the shop. Quenching works for me.

Jeff

[David Vanvorst]

Jeff,

I might have over-heated a blade or two when I first started, but I am overly cautious when grinding. I quench frequently, and I don't grind up to the edge.

Thanks for pointing it out, though.

-David

[Stuart Tierney]

Just quickly, since it seems you've fixed the problem, or worked around it.


You never got rid of the wire edge, and that's what was folding over.

It was as simple as that, and the fix would have been simple, and you'd have not needed to buy anything.

The strop is taking that very small wire edge off, as they tend to do, so problem solved.


Stu.