Making Wood Carving Knives and Tools from Everyday Objects
I was looking through my carving bag one day and realized something.
I've made carving knives and small carving tools out of a surprising number of everyday objects.
Old hacksaw blades.
Motorcycle spokes.
Files.
Hex wrenches.
Planer blades.
Even concrete nails.
Some worked better than others.
But that's part of the fun.
There's something satisfying about taking an old piece of steel that has outlived its original purpose and turning it into a tool that cuts wood.
You finish it, put it into a piece of basswood, and think:
Gosh, I made that.
And it actually works.
If you enjoy experimenting with tools, there are quite a few pieces of steel hiding in workshops, garages, and junk drawers that can make interesting little carving tools.
There are just a few things you need to understand before you start grinding.
First, A Word About Mystery Steel
Before getting into my list, there's something I understand better today than when I originally wrote about making tools from everyday objects.
When you pick up an old file, saw blade, spring, or piece of wire, you may not know exactly what steel you're dealing with.
I call that mystery steel.
You may know the object was hardened for its original purpose.
That doesn't necessarily tell you:
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The exact steel alloy
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How it was heat treated
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Its current hardness
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Whether it's hardened throughout
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How brittle it may be
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Whether it will hold a carving edge
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Whether grinding has already affected its temper
That doesn't mean you can't make a tool from it.
I've done it plenty of times.
It just means you're experimenting.
And that's part of what makes this fun.
Why Make Carving Tools from Old Steel?
You certainly don't have to.
If your goal is simply to own a good carving knife, buying one is considerably easier.
But that's missing the point.
Making your own little carving tool teaches you quite a bit about how cutting tools work.
You begin paying attention to:
Blade thickness.
Bevel angles.
Edge geometry.
Hardness.
Handle design.
And how small changes in any of those things affect the way the tool moves through wood.
You also get to make tools that may not be commercially available.
A tiny chisel for one particular cut.
A narrow detail tool.
A miniature gouge.
A little skew.
Sometimes you don't know you need a tool until you're halfway through a carving.
That's when making your own starts getting interesting.
You Don't Always Need a Forge
Many of the little tools I've made from existing objects didn't require forging.
The basic idea is simple.
Start with a piece of steel that already has useful properties.
Then remove material until you have the shape you want.
That's stock removal.
Depending on the size of the tool, you might use:
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A small belt grinder
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Bench grinder
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Dremel-type rotary tool
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Files
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Sharpening stones
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Wet/dry abrasive paper
For very small tools, you can sometimes do nearly everything by hand.
The important part is controlling heat.
Keep the Steel Cool While Grinding
If you're working with steel that is already hardened and tempered, overheating it during grinding can ruin the properties you're trying to preserve.
That's why I grind slowly.
And cool frequently.
Keep a container of water beside the grinder and dunk the steel often.
Don't wait until the piece is too hot to hold.
By then you've already put quite a bit of heat into a very small piece of steel.
Thin carving blades heat up surprisingly fast.
What If the Steel Turns Blue?
One warning sign of excessive heat is a change in the temper color of the steel.
Blue coloration can indicate that you've heated an area considerably.
On a finished cutting edge, that's not something I want to see accidentally.
My old advice was simple:
If you turn the cutting area blue, grind back beyond the affected area and start again.
That's still a reasonable shop rule when working with unknown hardened steel, but remember that color alone doesn't tell you everything about the underlying heat treatment.
The better approach is not getting it that hot in the first place.
Cool frequently and take your time.
Mechanical Hacksaw Blades
Old mechanical hacksaw blades were one of my favorites.
I'm not talking about Sawzall blades.
I'm talking about the big, heavy blades used in older power hacksaws.
Some are around a foot long and provide quite a bit of material for experimenting.
Depending on the particular blade construction, you may be able to cut several small carving tools from one blade.
I've used this type of material for small knives and other carving tools.
Just remember our mystery-steel rule.
Not every hacksaw blade is made from the same material or constructed the same way.
Experiment and test the finished edge.
Motorcycle Spokes
Motorcycle spokes can make interesting little tools.
They're particularly useful when you need a very small cross section.
I think of these as microtool material rather than something I'd use for a conventional carving knife.
A small piece of steel like this can become a:
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Tiny chisel
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Micro skew
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Small scraper
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Detail tool
The fun is deciding what shape would help with the carving you're working on.
Music Wire
Music wire is another material I've used for very small carving tools.
It's readily available in different diameters and gives you a convenient starting shape.
With small sections, you may not even need powered grinding equipment.
You can sometimes shape the working end progressively with stones or abrasives and then finish by stropping.
Again, we're talking about small specialty tools rather than a full-size carving knife.
For that purpose, it can be pretty handy material to experiment with.
Old Straight Razors
Remember those old straight razors Grandpa used?
I've experimented with those too.
An old straight razor gives you thin hardened steel that was already intended to take a very fine cutting edge.
But be careful here.
Straight razors are thin.
Very thin.
That can make them useful for experimentation, but it also means you need to think carefully about what kind of carving tool you're making.
A carving knife experiences different forces than a razor shaving hair.
Don't assume that because the steel takes a razor edge, it's automatically appropriate for every carving knife design.
And if the razor has any collectible or historical value, leave it alone.
There are plenty of other pieces of steel to experiment with.
Hex Wrenches
Yep.
Those L-shaped hex wrenches.
The ones that seem to multiply in the junk drawer every time you assemble a piece of furniture.
I've used them too.
The small cross section can lend itself to miniature carving tools.
Depending on the wrench, you may be able to grind one end into a little chisel, scraper, or other specialty shape.
Are all hex wrenches made from the same steel?
No.
That's why this is experimentation rather than a recipe.
Make the tool.
Sharpen it.
Test it.
See what the edge does.
Chainsaw Files
Old chainsaw files can provide another source of hardened steel.
The round cross section naturally lends itself to certain small tool shapes.
Once the file is no longer useful for sharpening a chain, there may still be enough material there to make a small carving tool.
Just remember that files can be quite hard.
Hard isn't always the same thing as tough.
Don't make assumptions about how much bending or side loading a small homemade tool can tolerate.
Needle Files
I used to buy little needle files at our local surplus store for about a quarter apiece.
Those days may be gone.
But I made quite a few small tools out of them.
Needle files are particularly interesting because the starting shapes are already useful for making miniature tools.
Flat.
Round.
Triangular.
Half-round.
Square.
With a little imagination, you can turn those shapes into some pretty useful little carving tools.
And when I was paying a quarter apiece, experimenting wasn't exactly a major financial decision.
If one didn't work?
I was out a quarter.
Surface Planer Blades
My dad used to give me old surface planer blades after he'd been planing ash planks.
Those gave me quite a bit of steel to work with.
Planer knives are interesting because they're already designed around cutting wood.
But that doesn't mean the original blade geometry is appropriate for a handheld carving knife.
You're starting with material.
You're still responsible for creating the tool.
And planer knives can have sharp edges on more than one side, so handle them carefully while you're cutting and grinding the material.
Concrete Nails
Yes.
Concrete nails.
I still have a flat-palm chisel I made from one.
That's the sort of tool I really enjoy making from found steel.
Not necessarily a conventional carving knife.
A little specialty tool.
Something that solves one particular problem.
Concrete nails provide a convenient piece of steel in a shape that's easy to experiment with.
Whether a particular nail has the properties you need is another matter.
Make it.
Test it.
Let the edge tell you.
Large Clock Springs
Old clock springs can provide long sections of thin spring steel.
The problem these days may be finding them.
The heavier ones are the interesting ones for tool making.
I've had some that would unroll into several feet of material.
Spring steel can be useful, but once again, you're dealing with unknown material unless you know exactly where the spring came from and what it was made from.
Treat it accordingly.
Large Bulldog Clips
This one usually gets people's attention.
You know those big black clips that hold stacks of paper together?
I've used the corners to make little gouge-like tools.
That's a perfect example of why I enjoy experimenting with everyday objects.
You look at something most people would throw in a desk drawer and start wondering:
What kind of carving tool could I make out of that?
Sometimes the answer is surprisingly useful.
Not Every Piece of Steel Is Knife Steel
This is worth repeating.
Just because something is steel doesn't mean it will make a good cutting tool.
A piece of mild steel can be ground razor sharp.
For a little while.
Then the edge may fold over almost immediately when it goes into wood.
For a carving tool, we need steel capable of taking and maintaining an appropriate hardened edge.
That's why objects originally designed as cutting tools, springs, files, and similar hardened components can be interesting starting points.
But even then, you don't always know exactly what you've got.
How Do You Know If Your Homemade Tool Worked?
Carve with it.
That's the fun part.
Sharpen the tool.
Strop it.
Put it into wood.
Pay attention to the edge.
Does it cut cleanly?
Does it require excessive pressure?
Does the edge roll?
Does it chip?
Does it stay sharp?
Can you strop the edge back easily?
You can learn quite a bit about a piece of steel simply by making a small tool and using it.
That doesn't tell you the exact alloy or Rockwell hardness.
But it does tell you something very practical:
Whether the tool works.
Edge Geometry Still Matters
Here's something making your own tools teaches very quickly.
Good steel doesn't guarantee a good carving tool.
You can have perfectly good hardened steel and still make a lousy knife.
If the blade is too thick behind the edge, it wedges through the wood.
If the bevel angle is wrong, it may not cut the way you want.
If the tool is too thick for the cut you're trying to make, it won't reach the work.
That's why I think making little carving tools is such a good education.
You start understanding that the cutting edge is only one part of the tool.
Geometry matters.
Put a Handle on It
Don't forget to leave enough material for attaching the tool to a handle.
I've made that mistake.
You get focused on creating the perfect little cutting edge and suddenly realize you didn't leave yourself much to hold onto.
For a small carving tool, the handle doesn't need to be complicated.
A simple wooden handle with an appropriately fitted tang may be all you need.
But make sure the tool is securely mounted.
A sharp piece of homemade steel coming loose from its handle isn't something you want to discover halfway through a cut.
This Is Experimenting, Not Production Knife Making
There's an important distinction between making a fun little carving tool from a discarded file and making a carving knife that you're going to sell to somebody.
If I'm making a Deepwoods carving knife, I want to know what steel I'm working with.
I want control over the heat treatment.
I want repeatable hardness.
I want repeatable blade geometry.
I want to know that the knife leaving my shop performs the way I expect it to perform.
Mystery steel doesn't give me that level of control.
That's why I look at these homemade tools differently.
They're experiments.
They're learning opportunities.
And they're fun.
Sometimes that's enough.
Want to Go Further? Learn About Heat Treating
Once you start making tools from known annealed steel rather than already-hardened objects, you've entered another part of knifemaking.
Now you need to understand:
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Hardening
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Quenching
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Tempering
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Steel selection
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Temperature control
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Rockwell hardness
That's where things get considerably more interesting.
You're no longer simply preserving the heat treatment somebody else put into the steel.
You're creating it yourself.
And that's an entirely different subject.
My Advice
Look around your shop.
You probably have potential little carving tools hiding everywhere.
Old files.
Saw blades.
Springs.
Wire.
Planer knives.
Things that have been sitting in a drawer for twenty years because you knew you'd need them someday.
Well, today's the day.
Pick something.
Keep the design simple.
Grind slowly.
Keep it cool.
Sharpen it.
Put a handle on it.
Then try it on a piece of wood.
Maybe it works beautifully.
Maybe it doesn't.
Either way, you'll probably learn something.
And if it does work, you'll have one of those little tools that stays in your carving bag for the next twenty years.
Not because it's the prettiest tool you own.
But because you made it.
That's worth something.
Frequently Asked Questions
Can you make a carving knife from an old file?
Possibly. Files are commonly made from hardenable steels, but the exact alloy and heat treatment vary. An old file can be useful for experimenting, but unless you know its composition and condition, treat it as mystery steel rather than assuming it will make a good carving knife.
Can you make carving tools without a forge?
Yes. Small carving tools can be made by stock removal from suitable steel. If you're working with already-hardened steel, controlling grinding heat is particularly important because overheating can affect the existing heat treatment.
Why do you cool the steel while grinding?
Grinding generates heat. On an already hardened and tempered piece of steel, excessive heat near the cutting edge can alter the properties you're trying to preserve. Frequent cooling helps control the temperature.
Can I use any piece of steel to make a carving knife?
You can grind almost any steel into a knife shape, but that doesn't mean it will hold a useful cutting edge. A carving knife needs steel with appropriate hardness, toughness, edge retention, and geometry.
How do I know what kind of steel an old tool is made from?
Unless you can identify the manufacturer, specification, or original material, you may not know. That's why salvaged steel is often called mystery steel. You can experiment with it, but you shouldn't assume its exact alloy or heat treatment.
Are homemade carving tools as good as commercially made tools?
They can work surprisingly well, especially for specialized little cuts. However, making tools from unknown salvaged steel doesn't provide the material and heat-treatment control that a knifemaker gets from using known steel.
What can I make from salvaged steel besides a carving knife?
Small chisels, skews, scrapers, microtools, detail tools, and small gouge-like tools can all be interesting projects. Sometimes salvaged steel makes more sense for a small specialty tool than for a full-size carving knife.
Do I need to heat treat a tool made from an old file or saw blade?
Not necessarily if you're deliberately preserving an existing suitable heat treatment while using stock removal. The difficulty is that with salvaged material, you may not know exactly what steel or heat treatment you started with. If you anneal or significantly alter the steel, proper hardening and tempering become a separate part of the project.
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