how to sharpen a really long blade?

[James Baker SD]

I have a 300mm long Japanese Machete for chopping plants in the garden. It is laminated in the Samurai sword tradition. It is still extremely sharp, but I know the day will come when it begins to dull. I have never sharpened this type of tool, one where the entire cutting edge cannot fit against the stone (Shapton ceramic stones) at once. Also it is a double bevel, different than my plane blades and chisels.

I want it as razor sharp as it is now because in a crowded area even a short stroke swing is enough to cut through most plants given the mass of the blade, but without damage to nearby plants I don't want to touch.

Any suggestions?

[David Bassett]

I suggest you look at knife sharpening information. (Basically, you do a section at a time. But saying that oversimplifies it.)

Jon at Japanese Knife Imports has a whole series on sharpening Japanese knives, both the traditional single-bevel ones and the western style double-bevel ones. I've always found his instruction very easy to follow (though I am very far from mastering the art.)

[Pat Barry]

I assume you already googled "sword sharpening" and that didn't help you?

[Derek Cohen]

Hi James

Have you tried an Eclipse honing guide? I am teasing

This is an occasion when you take the stone to the blade, rather than the blade to the stone. Hold the machete firmly on a table top and work away from the edge (never towards one). Check out exampes of sharpening drawknives.

On a train to London

Derek

[george wilson]

The stones must be held in the hand and honed in a circular motion up and down the blade. Take special care to keep the tips of your fingers from protruding over the side of the stone. You might want to start off with a circular "axe" stone. Some have grooves around their edges for the fingers. They are about the size of a hockey puck. They are also good for starting a good edge on long jointer or planer blades by hand.They will take care of any little nicks and begin getting your blade sharp,but you will need finer stones to get a really sharp edge.

When I was in college our class went to a tour of a veneer factory. We saw an old guy sharpening a 10 foot veneer machine blade. He used 2 circular stones. One on the angle of the bevel. The other held flat against the flat side of the blade. He moved the stones up and down the blade with very rapid circular motions,which gave me the willies! He said that he never cut himself. These blades had to be very sharp in order to cut thin veneer slices across the grain of all kinds of tropical wood logs.

[Bob Glenn]

This sounds like a job for the Drawsharp tool developed by Peter Galbert. It is a device that is held in one hand with the blade to be sharpened in the other, then moved along the bevel of the blade. An adjustable stop locks in the bevel angle to be sharpened while the abrasive is moved back and forth along the length of the blade at the desired angle. I'm not one for gadgets and have always sharpened my draw while held in a vise while moving silicone carbide paper wrapped around a block along the blade. However, I finally purchased a Drawsharp, less the 100 dollars, and I am impressed with the results. BTW, no connection with Galbert or the manufacturer. Bob

[Andrew Gold]

I think you're overthinking this issue- do you know how to sharpen a kitchen knife?

It's relatively easy in my experience, as needs much flatter bevels than a plane blade or large chisel needs.

Not trying to dismiss the question, but with a stone and some time you'll have no trouble.

[Jim Koepke]

My machete gets sharpened on bench stones not much different than a kitchen knife.

This thread reminds me of a couple seconds from a scene in an old move, Paint Your Wagon, where a person is sharpening a Bowie knife on a hand held stone. He pushes the blade up the stone on one side, flips the knife and pushes the other side up the stone.

jtk

[Tim Atkins]

I sharpen my machete with a mill bastard file. I have hit too many rocks in the ground and fence post to have a samurai garden tool.

[Ryan Mooney]

Take special care to keep the tips of your fingers from protruding over the side of the stone.

And the heal of your hand as well

Quite a few years back I had sharpened a friends machete to perhaps and excessive degree of sharpness for such a tool and was teaching him how to maintain the edge. After a description of how to hold and move the stone and the usual warnings about keeping your fingers above it (this was a smaller square stone so more difficult that an axe stone would be) he proceeded to take a circular swipe and shaved the pad of skin right below his thumb off. Looking at the silver dollar sized hole the response was "well I guess its sharp anyway". Subsequent post-healing attempts were a bit more cautious on his part

[Pat Barry]

I assume you already googled "sword sharpening" and that didn't help you?

Ok -
Sword sharpening video. Watch this one and the next one that comes up

[Brian Holcombe]

There is something to consider, that Machete is probably sharpened with a 'Hamaguri' style bevel. You'll want to research this a bit more before damaging the profile with another method.

There is a book titled 'Japanese Sword Polishing' which is very helpful for this sort of thing.

I sharpen a sushi knife with a Hamaguri bevel on one side, it takes some getting used to.



You may not be able to make it out in this photo, but the bevel is actually slightly rounded and the extreme edge is finished with a different stone than the remainder of the bevel.

The extreme edge is finished with a Nakayama asagi, which is a very hard and fine stone. The remainder of the bevel is finished with a Uchigumori stone, which can become hollow after some use and therefore more suitable to creating an even finish on the blade.

[Curt Putnam]

I use a 1" x 42" belt grinder with a leather belt and green compound for all my knife shaped objects. Superb edges in seconds. A 1 x 30" would work just as well. The ideal is probably a 2" horizontal grinder with a belt SFPM of less than 1000.

[James Baker SD]

Lots of good tips and leads, thanks guys.

Brian, it is not a really high quality blade like your knife, think I spent under $100 on it. I can see the lamination layers and bevel looks (with just eyeball) to have a micro bevel on it. I will research the Hamaguri if only for my education.

However, I do want to keep it sharp. I am not strong, my wife has over-planted our garden (things too close together so a long swing to accelerate the blade is not possible) and right now I can take down a 3 or 4" giant bird of paradise seedling with only the force my arm can develop in about 6" of swing. Given my strength and the crowded garden, that is very useful to me. I keep my other hand and my feet out of the way

[Jim Koepke]

Lots of good tips and leads, thanks guys.

Brian, it is not a really high quality blade like your knife, think I spent under $100 on it. I can see the lamination layers and bevel looks (with just eyeball) to have a micro bevel on it. I will research the Hamaguri if only for my education.

However, I do want to keep it sharp. I am not strong, my wife has over-planted our garden (things too close together so a long swing to accelerate the blade is not possible) and right now I can take down a 3 or 4" giant bird of paradise seedling with only the force my arm can develop in about 6" of swing. Given my strength and the crowded garden, that is very useful to me. I keep my other hand and my feet out of the way

Sharp tools are a great help and pleasure in the garden.

It has taken a lot of work, but my older scythe, with an ~24" 'brush' blade, has finally been honed enough to work efficiently. The last time it was sharpened the blade was removed from the snath (scythe speak for handle) and held in a vise. It still has room for improvement. It works best with a motion that swings and pulls through the vegetation. From the trade mark on the blade it appears to be made before 1860.

My newer scythe has a 36" blade. It is not well suited for the weeds and ferns that grow in my yard and pasture.

jtk