Investing in Sharpening Stuff

[David Weaver]

Your stones must be crowned one way or another. It's very unusual to have the iron proud at the corners, and only a crowned stone would do it unless you're draping one side of the bevel or back over the edge of the stones the entire time you're sharpening.

You have a nice kit of gear (oilstones and glasstones), when you get this straightened out, it will serve you well.

You may be lamenting that you could get a granite plate instead of a diamond hone, but most people prefer the diamond hone - even one that is worn. Just use it often enough on your stones such that they don't get too far out of flat.

The proud corners on an iron is a puzzling thing, though, and I think when all is said and done, you'll find something concave or loose somewhere such that the center of the stone is allowed to be higher than the sides.

[Harvey Pascoe]

I have a diamond plate, diamond fused to plated steel that is 20 years old, a little dull but still cuts fast enough. Its a low grit used for fast cutting. Looking at those DMT things, its easy to see why they wear out fast: less than half the surface is diamond, the rest is plastic. A diamond plate costs about double but will last 5X longer.

[Bill Moser]

I haven't tried the "scary sharp" method yet. According to Chris Schwarz, that method actually costs more in the long run, since you have to replenish your sandpaper supply quite often. I get by with a 400/1200 diamond stone, and a 4000 grit shapton, and I use the diamond stone to flatten the shapton. This is, for me, a quick, low-mess solution.

[Dale Cruea]

I found the problem.... When I purchased my new stones I also purchased a Dia-Flat. When I was flattening my stones I was pushing and pulling from the long side. I did not feel the stone rock just a small amount. This caused the stone(s) to be crowned down the middle. I now flatten the stones by pushing along the narrow side. No crown. Thanks to all that offered suggestions. It gave me a place to start.

[Bill Nenna]

This is my first post since joining. Sharpening...sigh... I think I have tried about everything. Oil stones, water stones, sand paper and DMT diamond stones. I settled on Diamond stones because I could not figure out how to keep my water stones flat. At the time I did not know you could flatten them on a granite plate and sand paper. I just purchased 4 Shapton glass stones. The appear to be working OK. The problem with diamond stones is that as you use them they start to get dull. The stone is still good but you need to rub more to get anything done.
I also have a question that you may be able to help with.
I have recently started using hand planes a lot. I have several, old and new. All have A-2 blades. I use an angle guide to hold my blades.
I have noticed in the last week or so all of my plane iron cutting edges have a concave in them. Not bowed out or down but bowed up.
I have tried everything I can think of to get rid of the bow but nothing works. It is only about .0015" or so but shows up when I take a very fine cut. I get 2 shavings, one on each side of the blade.
I can understand if it were convex but, concave.
I went back and tried my sand paper on granite and my diamond stones.
I lapped my new stones flat and tried them. Nothing appears to work.

If the back of the blade is flattened then then your problem has to be your technique. If you are exerting pressure on your guide, then your doing it wrong. There should be no pressure put on the wheel of the honing guide. The only pressure should be on the tip of the blade about a third of the way in from each edge evenly. Putting a slight curve on the blade, if you choose, should be a deliberate process of adding a set number of strokes with pressure near the edge of the blade then half as many strokes with pressure put half way between the side and the center of the blade, skip the middle and continue the same process on the other side.

Since you problem is the same using stones or glass I have to believe it has to be incorrectly applied pressure.