Help a Newbie - Planes and Waterstones

[Dave Warner]

Hi All,

I have a question about the results of my sharpening efforts. I'm pretty new to all this, but I have read Lee's Guide To Sharpening and feel I have pretty good idea of what to expect.

Here's the deal. Using the Lee Valley Low Angle Jack Plane and the blade in question has a 25* main bevel. To sharpen I'm using 1200 and 4000 grit waterstones and the LV Mk2 honing guide. I'm not using the camber roller assembly. The plane seems to be working as expected and even a newbie like me is getting some nice thin shavings with little effort.

In terms of sharpening what I see is the cutting marks, left by the water stones, have a distinct curve. My related question is, is this expected? See the photo below ... I would have thought the cut from the stones would be parallel to the edge. As of this photo I've touched up the edge twice so far.



Is this just the nature of the LV Blade?

Does this cut pattern indicate a problem with my technique?

Seems to cut ok, so maybe I just should not sweat it?

I'm also seeing something similar though less pronounced when sharpening a smaller 38* blade for the LV LA Block Plane.

I'm using a flattening stone to keep the cutting surfaces of the stones flat and according to some decent straight edges everything should be flat.

So that's about it. I'd love to hear some comments/suggestions from the neander community ... you guys are great and SMC is proving to be a wonderful resource for me.

Have Fun!
Dave

[Robert Rozaieski]

That looks like the result of a dished stone. Another possibility is that you are putting more pressure on the corners than the middle of the iron when you hone. Waterstones, especially the 1000 are very soft and will wear very fast.

[Bill Moser]

Dave -- it has to be that your stones are convex. As Robert said, waterstones wear fast, like in 3 seconds if you're bearing down hard in the center of the blade. I don't think a straightedge will pick up the apparent dish you're seeing, but i could be wrong. What are you using to true the stones? float glass, or some other good reference surface?

[Mike Henderson]

I agree with Robert that your stone is probably dished. But when you sharpen an iron you usually want the edge to curve some amount. But we're talking a really small amount for most applications. You can usually get the amount of curve necessary just by pushing hard on each side of the iron for a couple of strokes on a fine stone (4000 in your case).

I use to think that you only had sharpen to a curve on smoothers but a real expert demonstrated to me recently the advantages of having a slight curve even on a jointer.

BTW, there are many ways to flatten a stone but the best I've found is to use a DMT extra coarse diamond plate. They're not cheap (about $100) and that's why I used other techniques early in my woodworking career. But once I had the money and bought one, I really appreciated it. In the meanwhile, wet-or-dry sandpaper on a flat surface - like a piece of glass or stone - will work fine.

You'll find that you'll flatten a lot. Before I start any sharpening session I flatten and if I even think the stone is going out of flat, I flatten again.

Mike

[And since I'm spending your money, eventually you'll want to get a finer stone, probably an 8000 stone. But for now, you'll do fine with what you have.]

[Mike Henderson]

Oops, I just noticed you said you're using a flattening stone. Those things are useless. VERY quickly they get out of flat and then you're just transferring the shape to the working stone.

The most common occurrence is that the flattening stone becomes convex. Here's the reason. As you use your working stone, you wear the center more than the sides. No matter what you do - even if you try really hard - you wind up using the center of the working stone more and it becomes concave.

Then when you put the flattening stone on your working stone to flatten it, the two stones make contact around the edges and not in the middle. So as you rub them together the outside of the flattening stone wears but not the middle - your flattening stone is becoming convex.

As you continue to use it, it gets worse. Eventually, it's convex to the point that it "fits" your worn working stone (which is worn more in the middle) so when you rub them together, the working stone is worn all over into a concave shape. By rubbing those two stones together you're guaranteeing that your working stone will have a hollow in the middle.

So throw that flattening stone away, or only use it to do coarse work (after you flatten it, of course). ONLY flatten a working stone on something that is guaranteed to be flat, like sandpaper on glass or a diamond stone.

Mike

[Bill Moser]

You'll find that you'll flatten a lot. Before I start any sharpening session I flatten and if I even think the stone is going out of flat, I flatten again.

I have pretty much every non-powered sharpening implement known to mankind. King waterstones go out of true very quickly (in sub-minutes for the coarse stones), but have a good feel. nortons last longer between lappings. i bought a set of shaptons about a year ago (1000, 5000, 8000), along with the basic lapping plate, and I'm amazed at how long they can go without going out of true. I can sharpen a dozen blades off the grinder, and they take only a few strokes on the lapping plate to true up again. And, there's almost no mess -- no need to soak the stones before use, just spray the surface right before use. and by the way, I'm in no way affiliated with the company!

[Mike Henderson]

I have the same Shaptons as Bill (1000, 5000, and 8000) and I still flatten often, as I mentioned above. The Shaptons are good stones, however.

Mike

[Shannon Vincent]

Sorry about the slight hijack...but Mike and Bill,do you have the Shapton glass/ceramic stones or the professional series?Do you feel that they produce a better or faster edge than the "scary sharp" method?(I am currently using the "scary sharp" with the LV mkII).

[Wilbur Pan]

The plane seems to be working as expected and even a newbie like me is getting some nice thin shavings with little effort.

I think this is the most important point -- your plane is working as you expected. If that's the case, I wouldn't sweat the curve you have too much.

I have the Shapton pro series. I think that using Shaptons is much nicer than Scary Sharp -- they cut more quickly than sandpaper, I'll take flattening over having to switch out sandpaper any day, and since I built a box that catches the water and serves as a platform to hold the stone, using waterstones is a lot less messy than Scary Sharp. But even though you have to flatten your waterstones, the Shaptons stay so flat that many times I've had to add more camber than I thought I had.

[Bill Moser]

Sorry about the slight hijack...but Mike and Bill,do you have the Shapton glass/ceramic stones or the professional series?Do you feel that they produce a better or faster edge than the "scary sharp" method?(I am currently using the "scary sharp" with the LV mkII).

Shannon - I have the professionals. I find them to be very fast, even with A2 steel, which seems to take longer to sharpen on other stones (not that I've done a rigorous comparison). And the shapton "compact" lapping plate works fast. Faster than glass I think (I don't have experience with large diamond plates). I only tried the scary sharp method once, it wasn't for me. If I remember correctly, I was tearing the paper often, undoubtedly due to bearing down too hard, which I tend to do with the initial stone. But I'm an impatient sharpener -- I just go for edges that produce shavings/cuts I'm satisfied with, not perfection.

Which reminds me (to get back on track) -- David Charlesworth also has a good section on sharpening in one of his books, and has recently made a DVD devoted to the subject. His "ruler technique" works great as a substitute for more laborious flattening of plane blade backs (it puts a microbevel on the back of the blade, so it's not for chisels). In the dvd, he makes a point of emphasizing stone flattening early and often as an integral part of the sharpening process, and even draws a grid on the stone with a pencil so that he can tell when he can stop flattening it. He's using Kings in the video, and its a great demonstration of technique, as well as showing just how quickly a stone can get dished.

[John Dykes]

I'll give a strong endorsement to the Charlesworth DVDs...

- Dykes

[Mike Henderson]

I have the professional series, also. I haven't used the glass backed stones but I hear good things about them. A teacher of mine has the set and likes them. I think the life will be about the same because you can only wear the professional down so far - then it gets too thin and fragile - so you can't use all of a professional stone.

They don't wear too fast, though. I've had mine for a couple of years and I've only worn about 1/8" off the 1000 stone (which gets the most wear).

Mike

[Tom Henderson2]

Hi Mike-

What is your technique for flattening your waterstones? I presume it is wet/dry sandpaper on glass or other flat surface? If so, what grit do you use, and how often do you do the flattening process?

Thanks in advance...

-TH

[David DeCristoforo]

Maybe it's just my eyes or the perspective in the pic but the edge does not look like it's curved. The curve you see appears to be more a result of an uneven hollow grind than a cupped stone.

[Mike Henderson]

Hi Mike-

What is your technique for flattening your waterstones? I presume it is wet/dry sandpaper on glass or other flat surface? If so, what grit do you use, and how often do you do the flattening process?

Thanks in advance...

-TH

I use a DMT diamond stone (or plate). I like the one that has one side extra coarse and one side coarse. It's somewhat expensive, about $100, but for me it's worth it.

Prior to getting the DMT, I used wet-or-dry sandpaper on glass. That works okay also but is just a bit less convenient - and you have to keep buying the sandpaper.

Mike