Sharpening trouble ~ help

[Michael Hartery]

Hello I have the NL standard block plane. After sharpening the edge of the blade comes out convex so the out side edges are higher that the middle of the blade edge. Shouldn't it be the opposite? The blade only catches the wood towards the out sides of the blade.
I have leveled all 4 of my water stones and I am using the Veritas honing guide,.
IS there any thing I am doing wrong? Any thing I should check for? This has been frustrating.
Any feed back will be great.
michael

[Simon Frez-Albrecht]

Are you pressing the blade harder in the middle? The LN blades are pretty thick, and shouldn't flex that much, but that could impact it enough to be giving you trouble. Any chance we could get a short video of you sharpening? That could help assess issues with your technique.

[David Weaver]

If you are using the honing guide and not allowing the iron to drape off the edge, the only answer is either that you're planing cupped wood, or you have stones that have a crown, even after you've flattened them.

Presumably you're planing down the edge of something that you know is flat, so that the cupped wood thing isn't a factor?

[John Coloccia]

Are you sure your test piece of wood isn't cupped? It's remarkably difficult to make a concave blade, IMHO. I don't even know that I could reliably do it if I wanted to. Your stones could still be crowned side to side. Those are the two things I can think of off the top of my head.

If you put a sharpie mark on the bevel and then go back to your stones, you can tell immediately where the stone is working. If it comes off evenly, then everything is flat and you have good technique.

[Tri Hoang]

It's hard to say what you did wrong. For a block plane, I'd like just a straight edge across.

I'd fix it by jointing the edge - position it 80-85* vertical on the 1000 stone (bevel down) and move it back/forth to get a straight edge. (start out with light pressure or you may have corners dig into the stone). Check it with a thick rule or against a known flat surface such as the sole of the plane.

Once the edge is straight across, look at the edge under reflecting light..you should see light reflecting off it, more so at the corners than the middle.

Put it back in the honing guide and put a bit more pressure on the left corner, do 10 strokes. Do the same to the right corner. Take a look at the reflecting light off the edge again. Repeat until you see a UNIFORM reflection across the entire edge.

Last, proceed with your honing process normally and use even pressure. Feel for the wire edge. It should be consistent across the entire edge. The biggest mistake I used to make in sharpening is not constantly checking/looking for feedback and altering my technique as required. It is especially very true when I was using a honing guide.

[Michael Hartery]

OK Thanks for responding so fast. When I put a steel square of the edge of the blade I see light in the middle but it makes contact on the sides. Perhaps Ill try leaning on the left and the right next time I sharpen on my water stone. I use 8000,1200,6000, then a white stone with a nagura.

[John Coloccia]

OK Thanks for responding so fast. When I put a steel square of the edge of the blade I see light in the middle but it makes contact on the sides. Perhaps Ill try leaning on the left and the right next time I sharpen on my water stone. I use 8000,1200,6000, then a white stone with a nagura.

If you have a crowned stone, that will just make it worse. Put that straight edge on the stone and see what you get. Removing the crown from a stone is difficult but it's very easy to think you've removed a crown because you can hit every part of the stone (removing your pencil marks, for example) while actually making a crown worse.

[Jim Koepke]

Michael,

Your profile doesn't show your location.

If you are in my area, send me a PM and maybe we can get together to solve this.

If not, you may live close to another member who will be happy to spend some time one to one on this problem.

jtk

[David Weaver]

Use your straight edge to check your stones, they must be crowned.

We definitely don't hear from people who have inadvertently turned their iron into a large beader too often.

[Dale Cruea]

I have the same problem and I have it on all of my plane irons. Hock, LV, LN and Stanley irons. I started getting convex cutting edges when I used diamond stones.
I changed to ceramic water stones and a diamond flattening plate. Still does it.
I look at my first pass over each stone to make sure that the center of the cutting edge is not hitting first. They appear to be hitting all the way across.
A straight edge shows that the center of the blade is down about .0015 or maybe .002".
The blades are flat across the back and straight across the cutting edge when I start. When finished the blades have a convex cutting edge.
I have checked my stones. all are flat. I even tried sand paper on my granite plate. Same thing.

[Jim Foster]

Are you making a hollow bevel before honing, or is there any other steps in your process before honing on your stones?

[Russell Sansom]

MIchael,
Even if it's a block plane a very slight crown on the leading edge works well, especially when you're starting out. As John said, it's pretty hard to get a hollow on a plane iron. I don't remember ever having done it. But take Tri's advice: joint the leading edge before you do anything else. Go just far enough to remove all the abnormalities from curve to nicks. Then sharpen down until the blunt flat leading edge disappears and becomes a bevel. If you leave yourself an almost microscopic flat on the front you can take it off with a small secondary bevel and all the geometry should come out with parallel-sided flats.
Are you sure the back isn't curved? If not, I'd guess there's something amiss with your technique. Send one of the experts a video and they can probably tell if that's the case. I'll volunteer if you want.

[Mark Roderick]

When I started I had the same problem, and after much angst I realized my stones weren't flat.

These are the possibilities:

--- Your wood isn't flat. You can test that with a straightedge, or winding sticks.

--- Your sharpening stone isn't flat. You can test that with a straightedge. To be sure, use sandpaper on glass to start with, not waterstones.

--- The back of your plane blade isn't flat. You can test that with a straightedge. The backs of plane blades have to be flattened, even those from Lie-Nielsen, in my experience.

--- The bottom of your plane isn't flat (this shouldn't matter if the back of the plane blade is flat, but still). You can test that with a straightedge.

Those are all the possibilities. You can't make a plane blade concave in the middle while honing, so this is one instance where poor technique doesn't explain the problem.

Please let us know when you find the culprit.

[Jessica Pierce-LaRose]

I've had this problem once - I was levelling my waterstones on a large sheet of sandpaper on granite, and had used a sort of figure eight motion to level them to use more of the paper. Things seemed flat when I was done - turns out it's easier to rock the stones than you might realize, and put a crown along them. I only flatten my stones front the back now, moving parallel to the long edge. A little out of flat this way might slightly change the bevel angle, but it's much better than ending up with a concave edge.

the other issue I had was my thinner Superstones kind of changed shape ever so slightly going from dry to wet - so I always make sure I get them as wet as I'm going to use them before I flatten.

[jamie shard]

+1 on stone flattening technique. When a stone is rubbed on an abrasive, the edges of the stone "see" the abrasive first. By the time the middle of the stone sees the abrasive, the abrasive has more slurry on it. As a result, the edges can wear down faster than the rest of the stone.

[Michael Hartery]

Thanks for all the great feed back guys.. I am going to digest all of this and ill post back with some of the results. This ended up being a great discussion.
michael

[Eddie Darby]

Hello I have the NL standard block plane.
michael
By 'NL', do you mean LN which is short for Lie-Nielsen?

[Jim Matthews]

What is used to flatten the stones?

Norton (http://www.amazon.com/s/?ie=UTF8&keywords=norton+flattening+stone&tag=googhydr-20&index=aps&hvadid=4274281795&ref=pd_sl_9gjg1pu7to_b) makes a simple, inexpensive silicon carbide gizmo to get them flat.
If you're using a Veritas guide, you might want to make sure the thumbscrew isn't deflecting the plane iron.
*Which I doubt*

Run a series of pencil lines across the stones and go through your flattening steps. If there are lines remaining toward the sides of the stone - Eureka.

Lastly, you can avoid some of this by sharpening sideways (laterally) to establish the secondary bevel, and stropping with your guide as normal to finish.
I do this with sandpaper on a granite substrate (cut out to fit a sink in a countertop).

[Mike Davis NC]

Could this be from the honing guide? Possibly bending the blade and putting a dip in the end? even on a flat stone...

Maybe try a different guide or sharpen freehand and see if there is a difference.

[Tony Shea]

Ah ha, Mike Davis finally nailed what I believe the issue to be. Surprised no one suggested this before. I started out free hand honing and have gradually moved more towards honing guides. I bought the inexpensive eclipse side clamping style honing guide and get repeatable results. But after all the rave I decided to check out the Veritas MKII honing guide just because I need another tool like I need another hole in the head.

I chucked my LN #7 iron in the Veritas MKII and went to town trying as hard as I could to get a perfectly straight edge (this is how I like to keep my LN #7). I was surprised to find out when I first started on the stones that the blade acted as though it had a slight camber, only producing metal filings in the center of the stone. But kept on sharpening.

I slipped the blade back into the plane thinking all was well. Hit a couple edges to test the sharpness and put the plane away. Next time I took out the #7 I needed to joint the faces of some boards. Low and behold I was getting shavings on both corners of the blade and whispy shavings in the middle (a concave edge). Took out the blade and checked it under a straight edge and proved the same thing.

Put it back into the Veritas honing guide and ended up with the same results. So just out of curiosity i put the blade in the eclipse guide and sure enough the edges of the blade were all that was being sharpended until things leveled out. Tried another Stanley blade in the Veritas and got the exact same results but a tad more extreme due to thinner blade.

Moral of the story is.... I believe your issue to be the Veritas MKII honing guide. Where the blade is being clamped from above and below, with a decent amount of pressure to keep the blade from moving, the faces of the two clamps NEED to perfectly flat or else your thinner and wide blades will follow the shape. And I have personally proved that the LN blades are thin enough to do this. I have yet to contact LV about my issue as I use the eclipse guide more often anyways unless dealling with akward bevels which are usually narrow enough to not be affected by the issue.

I appologize for the length of the post but I do know where your coming from as I personally struggled with the same exact issue before I actually figured it out.

[Jessica Pierce-LaRose]

Tony's example can happen with the eclipse guide as well, btw - I had one where when clamping, the play in it sort of flexed up the middle, bowing the blade. Made a few adjustments to it as shown in the recent Lie Nielsen video and on Chris Schwarz's blog and it fixed things.