Diamond Sharpening Stones for Wood Carving Knives
Diamonds are forever.
Who doesn't remember that James Bond title?
Don't worry. I'm not going to start the old argument over who made the best James Bond.
At least not yet.
We're going to talk about a different kind of diamond—the kind you'll find on a diamond sharpening stone.
I've used several different sharpening systems over the years, and diamond plates have become one of the tools I like having around the shop.
They're flat.
They cut efficiently.
They don't need to be soaked.
And if I happen to drop one on the concrete floor, there's a pretty good chance I'll still have one sharpening stone instead of two broken pieces.
That last part matters more to me than I'd like to admit.
But durability isn't the main reason diamond sharpening stones work well for wood carving knives.
It's the flat, consistent sharpening surface they provide.
What Is a Diamond Sharpening Stone?
A diamond sharpening stone—or diamond plate—is usually a flat metal plate with industrial diamonds bonded to the sharpening surface.
Those tiny diamond particles are the abrasive.
As you move the knife across the plate, they remove steel from the blade and reshape the cutting edge.
The principle isn't much different from any other sharpening stone.
The abrasive does the cutting.
What makes diamond different is how hard and aggressive that abrasive is.
Diamond plates can remove steel efficiently while maintaining a very flat sharpening surface.
For certain carving tools, that's a useful combination.
Why Flatness Matters
One of the biggest advantages of a diamond sharpening plate is that it stays flat.
Traditional sharpening stones can gradually wear unevenly and develop a hollow or "dish" in the middle.
That doesn't mean traditional stones are bad.
It simply means they occasionally need to be flattened.
A quality diamond plate doesn't dish in the same way.
For carving tools with flat bevels, that can be especially useful.
Think about:
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Scandi-ground carving knives
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Flat-ground carving knives
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Chisels
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Skew chisels
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Other straight-edged carving tools
If you're trying to maintain a flat bevel, it helps to have a flat surface underneath it.
Pretty simple.
Deepwoods Tip
This is one of those areas where sharpening equipment can actually change the geometry of your tool without you realizing it.
If you're trying to maintain a flat bevel on a stone that's badly dished, eventually you're going to change that bevel.
The flatter the sharpening surface, the easier it is to maintain the geometry that was originally put into the blade.
Diamond Plates Can Also Flatten Other Stones
There's another advantage to having a flat diamond plate in the shop.
It can be used to flatten some traditional water and oil stones.
As those softer stones wear and become dished, a sufficiently coarse, suitable diamond plate can provide a reference surface for bringing them back to flat.
So even if diamond isn't your primary sharpening system, a diamond plate can still earn its place on the sharpening bench.
Just make sure the particular plate you're using is suitable for stone flattening according to its manufacturer.
Continuous vs. Interrupted Diamond Plates
If you start shopping for diamond sharpening stones, you'll probably notice two basic surface designs.
Some have a continuous diamond surface.
Others have holes, recesses, or an interrupted pattern across the plate.
There's a reason for that.
When you sharpen a knife, the abrasive removes tiny particles of steel. That mixture of metal and sharpening residue is often called swarf.
Recesses in an interrupted plate give some of that material somewhere to go instead of leaving all of it between the blade and the abrasive.
That can work very well for larger blades.
But there is a tradeoff.
If you're sharpening very small carving tools, narrow chisels, or other fine edges, those holes can get in the way.
The edge of a tiny tool can catch or drop into the interrupted areas instead of staying on a continuous sharpening surface.
For that reason, I generally prefer a continuous diamond surface for small carving tools.
It gives the entire edge something to ride on.
What Grit Diamond Stone Should You Use?
This is where sharpening can become more complicated than it needs to be.
There are a lot of grit choices.
You don't need all of them.
For most carving knives, I think in terms of what I'm trying to accomplish rather than trying to build a collection of every grit available.
Coarse Diamond Stones
A coarse plate removes steel quickly.
That's useful when:
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Repairing a damaged edge
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Removing small chips
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Correcting a bevel
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Reshaping an edge
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Working on a particularly dull tool
I don't use a coarse stone for routine maintenance unless there's a reason.
It removes steel quickly.
That's its job.
Medium Diamond Stones
A medium plate is useful for establishing or restoring an edge that has become too dull for stropping.
For a carving knife that simply needs sharpening rather than repair, this may be all the stone you need before moving to something finer.
Fine Diamond Stones
Fine diamond plates refine the scratches left by the previous sharpening step and prepare the edge for stropping.
If your knife isn't badly dull, a fine plate may be enough to restore it without starting with anything coarser.
That's why I don't automatically start sharpening with the coarsest stone on the bench.
Start with the finest abrasive that will actually do the job.
You'll remove less steel and spend less time correcting scratches you didn't need to create in the first place.
Do You Need Three or Four Diamond Stones?
Probably not.
For a wood carving knife, I like keeping the sharpening process simple.
If you're maintaining the knife regularly with a strop, you shouldn't need to work through a long progression of stones every time the edge needs attention.
A couple of useful grits can handle most sharpening situations.
Then let the strop do the final refinement.
That's an important distinction.
The diamond plate and the strop aren't competing with one another.
They're doing different jobs.
The Stone Creates the Edge. The Strop Refines It.
This is the same principle I use throughout my sharpening routine.
A sharpening stone removes steel and restores the cutting edge.
A strop maintains, deburrs, and refines that edge.
Before I put a carving knife on a diamond stone, I normally try stropping it first.
If the strop brings the knife back, I'm finished.
There's no reason to remove steel from an edge that doesn't need to be rebuilt.
Eventually, however, stropping stops being enough.
Maybe the knife doesn't bite into the wood the way it used to.
Maybe it requires more pressure.
Maybe you've developed a small nick.
That's when the diamond plate comes out.
Use the stone only long enough to restore the edge.
Then go back to the strop.
Deepwoods Tip
Every pass across a sharpening stone removes steel.
That's exactly what it's supposed to do.
But once the edge is restored, continuing to grind doesn't make the knife "more sharp."
It just removes more steel.
Strop often.
Sharpen when necessary.
That simple routine will keep a carving knife working for a very long time.
Should You Use Water on a Diamond Sharpening Stone?
I use water.
Not because the plate necessarily requires it.
I just find that a little water helps keep the sharpening surface clean and carries away some of the swarf as I'm working.
Some diamond stones are designed to be used dry.
Others can be used with water.
Follow the manufacturer's instructions for the particular diamond plate you own.
One thing I would avoid is assuming every sharpening product works exactly the same way.
It doesn't.
Do Diamond Stones Need Oil?
Usually, I wouldn't reach for traditional honing oil unless the manufacturer specifically recommends it.
One of the advantages of many diamond sharpening systems is their simplicity.
A little water—or sometimes nothing at all—is enough.
Again, follow the instructions that came with the plate.
What About Diamond Stones for Gouges?
A flat diamond plate is great for a flat or straight edge.
A gouge is another matter.
The curved cutting edge of a gouge doesn't naturally match a flat sharpening surface.
There are curved and shaped diamond sharpeners made specifically for gouges and other concave tools.
That's really the same lesson we see throughout sharpening:
The sharpening surface needs to match the geometry of the tool.
A flat plate works beautifully for a flat bevel.
A curved tool may require a curved sharpening surface.
Diamond vs. Ceramic Sharpening Stones
I've used both.
I don't think one automatically wins.
Diamond plates have several advantages.
They cut efficiently, stay flat, require very little preparation, and they're durable.
Ceramic stones can also produce an excellent, refined edge and work very well toward the finer end of the sharpening process.
If you're wondering which one you should buy, I'd ask a different question:
Which sharpening system are you most likely to learn and use consistently?
That's more important.
A carver who knows how to use one good ceramic stone will get better results than someone with six diamond plates who hasn't learned how to sharpen.
And the reverse is equally true.
The equipment helps.
Technique matters more.
Advantages of Diamond Sharpening Stones
There are several reasons I like diamond plates for carving tools.
They stay flat.
That's particularly useful for Scandi grinds, flat bevels, chisels, and straight cutting edges.
They cut efficiently.
Diamond abrasive removes steel quickly compared with many traditional sharpening stones.
They don't need soaking.
You can pick one up and start sharpening.
They're durable.
There's no traditional stone to crack or break if the sharpening plate takes an occasional knock around the shop.
They're available in different grits.
You can choose an abrasive appropriate for anything from edge repair to fine sharpening.
They require very little maintenance.
Keep them clean and use them according to the manufacturer's directions.
Disadvantages of Diamond Sharpening Stones
Diamond isn't perfect.
Coarse plates can remove steel very quickly.
That's useful when you need it and unnecessary when you don't.
New diamond plates can feel especially aggressive.
Many plates settle into their normal cutting character after some initial use.
Interrupted surfaces aren't ideal for every tool.
Very small carving tools may be easier to sharpen on a continuous surface.
They don't replace a strop.
Even after fine diamond sharpening, I still finish my carving knives on leather.
They aren't ideal for every tool shape.
Flat plates are designed primarily around flat or straight sharpening surfaces. Gouges and other curved tools may require something different.
How I Use a Diamond Stone on a Carving Knife
My sharpening routine is pretty simple.
First, I strop the knife.
If that restores the edge, I go back to carving.
If it doesn't, I choose the finest diamond plate aggressive enough to restore the edge.
I maintain the existing bevel rather than trying to create a new one.
I sharpen only until the edge has been re-established.
Then I return to the strop.
That's it.
I don't work through five stones just because I own them.
The goal isn't to spend the afternoon sharpening.
The goal is to get the knife cutting properly so I can spend the afternoon carving.
How Do You Know When the Knife Is Sharp?
Test it on wood.
That's what the knife was made to cut.
A properly sharpened carving knife should:
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Enter the wood without excessive pressure
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Produce smooth, controlled shavings
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Slice rather than wedge
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Leave a clean surface behind
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Follow the cut without feeling like you have to force it
You can shave arm hair or slice paper if you enjoy doing that.
But I'm making a wood carving knife.
The test I care about is wood.
Don't Overcomplicate Sharpening
Spend enough time around woodcarvers and eventually you'll hear some pretty serious sharpening discussions.
Diamond. Ceramic. Water stones. Oil stones.
Sandpaper. Microns. Grit ratings. Polishing compounds.
There is plenty to learn if you're interested.
But you don't need a laboratory on your workbench to keep a carving knife sharp.
You need a flat sharpening surface, an appropriate abrasive, a good strop, and enough practice to maintain the geometry of the knife.
That's really it. Learn your equipment.
Pay attention to what the edge is telling you.
And remove only as much steel as necessary.
My Advice
If someone asked me whether diamond sharpening stones are worth having for wood carving knives, I'd say yes.
They're simple.
They're flat.
They cut efficiently.
And they'll handle everything from repairing an edge to routine sharpening depending on the grit you choose.
But I wouldn't tell you to throw away a sharpening system that's already working for you.
If your ceramic stones, water stones, oil stones, or sandpaper give you the edge you want, keep using them.
There isn't a prize for owning the most expensive sharpening equipment.
The only thing that matters is the edge you put on the knife.
And since I brought it up at the beginning, I suppose I should settle the other question too.
Pierce Brosnan was a good James Bond.
But Sean Connery will always be the best.
There.
I got my two cents in.
Keep carving.
Frequently Asked Questions
Are diamond sharpening stones good for wood carving knives?
Yes. Diamond stones cut efficiently and maintain a very flat sharpening surface, making them particularly useful for carving knives with flat bevels, Scandi grinds, and straight cutting edges.
What grit diamond stone should I use for a carving knife?
Use the finest grit that will efficiently correct the condition of the edge. Coarse stones are useful for damage and reshaping, while medium and fine stones are more appropriate for ordinary sharpening and refinement. Regular stropping can greatly reduce how often coarse sharpening is necessary.
Do you use a diamond stone or strop first?
I strop first. If stropping restores the cutting edge, there's no reason to remove steel with a sharpening stone. If stropping no longer works, I sharpen the knife and then finish by returning to the strop.
Should you use water with a diamond sharpening stone?
I prefer using a little water because it helps keep the sharpening surface clean. However, diamond plates vary, so follow the manufacturer's directions for your particular stone.
Do diamond sharpening stones need to be flattened?
One of the main advantages of a diamond plate is that it maintains a flat sharpening surface and doesn't dish like many traditional stones. Some diamond plates can actually be used to flatten other sharpening stones.
Is a continuous or interrupted diamond plate better for carving tools?
For very small carving tools and narrow edges, I prefer a continuous surface because the entire tool remains supported. Interrupted plates can work very well for larger knives because the recesses provide somewhere for sharpening residue to collect.
Are diamond stones better than ceramic stones?
Not necessarily. Diamond plates cut efficiently and maintain a flat surface, while fine ceramic stones can produce an excellent refined edge. Both can work very well for carving knives. Consistent technique matters more than choosing one material over the other.
Do you need to strop after using a diamond stone?
Yes. I finish sharpening a carving knife on a leather strop. The diamond stone establishes the edge, while the strop removes the remaining burr and refines the cutting edge before the knife goes back into the wood.
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