Making a Wood Carving or Marking Knife with Disposable Blade

Swann Morton scalpel blades have become popular for marking knives. They are a high quality, carbon steel, disposable blade available from the U.K. David Barron, among many others, uses them in his marking knives, epoxied solidly into the handle. The carbon steel blades are easy to sharpen and take a keen edge. I ordered some last fall and have considered several ways of making the blades replaceable.

Swann Morton 01 Scalpel

I started with a scrap of Spanish cedar. Cut a slot through the end deep enough for the blade. Drilled and countersunk a screw hole to retain the blade. Then sketched and cut out the handle shape. Full details are in the build video. My apologies for the lack of pictures but this was spontaneous and slotting, drilling, and sketching the handle blank was a less than a five minute minute job.

The blade is secured with pieces of walnut veneer that fit like splines in the kerf above and below the blade. As seen in the video, I did not adequately glue the veneer or didn't allow enough drying time (probably both), and the spline failed. On the second try I used cyanoacrylate glue which is holding up fine so far. There are stronger ways to secure the blade but I wanted to try this first as it's the easiest. If it fails again I will insert a brass pin above the blade. An alternative is an inner frame of metal with a cut out for the blade, then attached wood scales. I might do that in a future video.

I am not a carver and did not make this knife with carving in mind but wanted to see how well it might work for chip carving. The blade is very thin and sharp, and had no issues slicing through poplar. My skills are obviously non-existent and it would be interesting to have an experienced carver's opinion.

Most prefer single bevel blades for marking knives as you can hold the flat of the blade against a straight edge. These are double bevel blades but by holding them at a slight angle you can achieve the same accuracy.

Video

Blades are available from:

scalpelsandblades.co.uk

or

Echo Iron Mongery on ebay

I have no affiliation with either seller.

Viking Chest: Part 3, worst carving ever and jigs are good

Things I learned in this phase of the prototype:

• I need way more carving practice
• A box joint jig would be super helpful for making wood hinges
• A hinge router jig is definitely worth making 

My prototype wood hinge turned out great, the actual hinges not so great. So I reused some cheap metal hinges that I salvaged from some long forgotten box. I scribed around the metal with a layout knife then cut the mortise with a chisel. This worked fine for the most part but that white pine is really soft and one of my mortises came out too deep. A few pieces of heavy paper shimmed it nicely and don't show. The lid still sits a tiny bit askew. I might gumption up and remove the hinges for more tweaking.

Before making more wood hinges I'd like to build a box joint jig. I just need to decide whether it will be Matthias Wandel's, John Heisz', or Stumpy Nubs' new Incra style jig; all have benefits. I'm partial to Stumpy's jig but am hoping to see a few others build it and give some feedback.

The elephant in the room (or blog) is my horrible carving job. The plan was to outline it with a marking knife then chip carve it but the wood was breaking out. So I remove most of the waste with a 1/4" chisel then cleaned out the bottoms with a Dremel router attachment. It was a good plan that I executed terribly. In my defense, the white pine is so soft and brittle that it just wanted to rip, tear, and fly apart. And the lines between the lines were too thin. A better approach would have been a relief carving but I gain some experience. I filled it in with black paint which despite what your eyes tell you, actually made it look better.

Sanding is done, edges are eased, and the first coat of amber shellac has been applied. More about that in the next entry.

Shop made chip carving knife with mahogany handle

Using a french curve I drew this pattern on 1/4" hardboard. 

Cut out and sanded the edges smooth.

The blade is a Dewalt reciprocating saw blade. I removed the yellow paint and cut the shape with a Dremel and cut-off wheel. The funky shape is partly because I had cut a piece off for a marking knife and partly so it would be secure inside the mahogany handle.

 

I carved a mortise out for the blade and secured with epoxy. 

You can see the handle shape traced on the mahogany blanks.

Excess wood was removed with a combination of saws, chisels, and sanding machines.

Handle finish is blonde shellac then buffed with 0000 steel wool and wax.

Blade was polished to 2000 grit using automotive sandpaper. Edge was ground by hand then sharpened with a diamond file and sandpaper.