Why Some Woods Are Harder on Your Knife Edge
Have you ever sharpened your carving knife, started a new piece of wood, and wondered:
Why is my knife getting dull so fast?
Sometimes it's the knife.
But sometimes it's the wood.
Different woods can be surprisingly different when it comes to edge wear. Hardness matters, but it isn't the only thing working against your cutting edge.
Sometimes the biggest problem isn't even the wood itself.
Harder Wood Usually Means More Work
In general, a denser, harder wood offers more resistance to your knife than something like basswood.
Compare carving dry maple with carving basswood and you'll feel the difference immediately.
You're asking that very fine cutting edge to do more work.
That doesn't mean you shouldn't carve harder woods.
Walnut, cherry, maple, and plenty of other hardwoods can make beautiful carvings.
It just means you may need to pay more attention to your edge.
Hardness Isn't the Whole Story
Here's where it gets interesting.
Two woods that feel similar in hardness don't necessarily treat your knife edge the same way.
Wood contains more than just wood fibers.
Some species can contain mineral deposits, including silica.
Silica is abrasive - think sand.
Instead of your knife simply slicing wood fibers, the edge is encountering tiny amounts of abrasive material along the way.
Some woods—particularly certain tropical species—are well known among woodworkers for dulling cutting tools faster than their apparent hardness would suggest.
Dirt May Be Worse Than the Wood
This is one I think carvers sometimes overlook.
Imagine picking up a nice piece of wood from outside.
Maybe it's been lying on the ground.
There's dirt embedded in the bark.
Maybe there's a little sand.
Then you start cutting through it with your freshly sharpened carving knife.
You may as well be introducing your knife to sandpaper.
Dirt and grit can be extremely abrasive.
That's why I'm careful when working near bark on wood that's been lying outdoors.
Clean it first.
And if necessary, use a saw or another tool to get through the dirty outer material before putting your good carving edge into it.
Bark Can Hide Grit
Bark itself isn't necessarily the problem.
It's what bark can collect.
Dirt.
Sand.
Dust.
Small mineral particles.
A log that's been dragged across the ground can carry quite a bit of abrasive material.
If you're working with freshly harvested spoon wood, take a good look at it before putting your carving knife to work.
A few minutes cleaning the blank can save you a trip back to the strop.
Sanded Wood Is Hard on an Edge
This is another big one.
Don't carve a surface you've already sanded unless you really need to.
Sandpaper leaves abrasive particles and sanding debris around the surface of the wood.
Put your carving knife back into that area and you're asking a very fine edge to cut through material that has just been worked with an abrasive.
My preference is simple:
Do your carving first.
Do your sanding afterward.
Once I've started sanding a carving, I consider the knife work pretty much finished.
Grain Can Make a Wood Feel Harder
Sometimes what feels like a hardness problem is actually a grain problem.
Straight grain may cut beautifully.
Then you reach:
-
A knot
-
Interlocked grain
-
Curly grain
-
A crotch
-
End grain
Suddenly the knife feels like it's working considerably harder.
The wood didn't necessarily become a different species.
The structure changed.
Changing the direction or angle of your cut can sometimes make a bigger difference than pushing harder.
Knots Are Tough on a Carving Edge
Anyone who has carved into a knot knows this one.
The grain changes direction.
The wood may be considerably denser.
And the knife suddenly stops moving the way it did a moment ago.
If the knot isn't important to the carving, I generally prefer avoiding it.
If it is part of the project, slow down.
Use controlled cuts.
And make sure the knife is sharp.
Dry Wood Can Feel Harder on the Knife
Moisture matters too.
The same species can feel very different green and dry.
Green wood generally cuts with less resistance.
Once that wood dries, you'll usually have to work harder to make the same cut.
That's one reason spoon carvers like green wood.
It doesn't mean dry wood is bad for your knife.
It simply means the edge is working against more resistance.
What Does This Mean for Stropping?
If you're carving a wood that's harder or more abrasive than basswood, you may need to strop more frequently.
That's perfectly normal.
Don't wait until the knife is noticeably dull.
When you feel the cutting performance beginning to change, give the edge a few light passes on the strop.
Regular stropping is much easier than allowing the edge to deteriorate until it needs sharpening.
Don't Blame the Steel Too Quickly
If your knife suddenly seems to be losing its edge faster than usual, think about what changed.
Did you switch wood species?
Are you carving dry wood instead of green?
Did you cut through bark?
Is the wood dirty?
Did you carve an area that had already been sanded?
Are you working through knots or difficult grain?
Sometimes the answer has nothing to do with the knife.
That's useful to know before you start changing sharpening angles or blaming the heat treatment.
Frequently Asked Questions
Do harder woods dull carving knives faster?
They can. Harder and denser woods generally require more cutting effort, but hardness isn't the only factor affecting edge wear.
Can wood contain abrasive material?
Yes. Some species contain mineral deposits such as silica that can increase wear on cutting tools.
Does bark dull a carving knife?
Bark can hold dirt, sand, and other abrasive particles that are hard on a fine cutting edge. Clean wood taken from outdoors before carving it.
Should I carve wood after sanding it?
I prefer to finish my knife work before sanding. Abrasive particles and sanding debris can be hard on a finely sharpened carving edge.
Should I sharpen more often when carving hard wood?
Not necessarily. Strop first. Harder or more abrasive woods may require more frequent stropping, but you only need to sharpen when stropping no longer restores the edge.
Continue Reading
Continue exploring Wood & Materials in The Deepwoods Handbook:
And from Sharpening & Knife Care:
