Monday, May 1, 2017


KN38 Paring Knife

I scribbled up this idea for a paring knife for the Canadian Knifemaker KITH 2017 on some plywood. I like the kiritsuke style angled tip. This one has a 4" blade and some AEB-L 1/16" fits the bill for a paring knife. The template PDF for KN38 is here.

A dip and drip in Condursal before heat treatment.

After drying the protective Condursal looks like this.

Into the oven at around 860°C (1580°F) and climb to 1060°C (1945°F) for a short soak.

Out of the oven and cooling fast. This is actually almost an orange yellow when first pulled out...

And between the copper plates for a minute.

This is what the blade looks like right out of the plates. A quick check with a file to see that it hardened correctly and it's into the first tempering pronto.

I put the blade into the tempering oven along with the two others I hardened during this session.

For the grind I want a full flat with distal taper. Because this stock is thin to start with there isn't much to take off.

A few dozen light passes on the VSM ceramic 60 grit alternating between long ways and across the blade. Dunking in the water bucket every pass or two.

Getting the symmetry right. Check the primary bevels against the light as they are being ground.

Here we see the distal taper from the handle to the point.

Checking the edge with the caliper. 0.015" is good for a paring knife before cutting the secondary bevel.

I am trying some sandpaper that I haven't used before. It's 3M Pro Grade P180.

I hand sanded the blade a bit with long straight strokes and lubricated with water.

Some light contact with the conditioning belt, being careful not to burn the blade. Cooling in water as usual.

Running the conditioning belt at around 4500 Surface Feet per Minute.

The belt does a really good job.

Here I have tacked on my small stencil and will prepare the electrolytic etcher for putting my mark on the blade.

After applying a few milliliters of stainless steel electrolyte to the pad, I give it two 15 seconds applications on ETCH and one 10 second application on MARK.

After etching I squirt with windex and wipe with a clean rag. A very light buffing with a scratchless blue Scotch-brite pad evens out the mark.

Blade is taped up and ready to start working on the handle.

Next step is the handle work.


Before starting on the handle I like to tape up the blade with 3M 233 masking tape. 

I've had a couple of maple burl scales that have been stabilized with Stick Fast sitting idle for a few years. Time to put them to use. They are a bit on the thick side for a paring knife, but we'll work them into a nimble handle.

Checking the bookmatch pattern I traced them and cut them out on the band saw.

I used some 3/16" wooden dowel to temporarily pin the scales to the tang. This helps keep everything lined up during drilling. 
Viewing the top the grain moves across the handle. I have a feeling this is going to look very good. 
I traced and cut out two pieces of spacer material with scissors and then punched out the holes for the pins with a heavy-duty paper punch. Spacers or liners give a nice visual effect like using a felt pen marker to outline a shape in a drawing. Mechanically it acts as a cushioning border between hard steel and softer wood. 
I took everything and pinned with dowels to shape the fronts.

With everything in place I cut the front close to the final shape with the band saw.

Then sanded in slack belt mode.

And buffed on the clean wheel. 

I cut some 3/16" 304 stainless rod for pins. Chamfered the ends a bit and scuffed them with 150 grit sand paper.

Everything is ready to clean.

After washing with acetone and prepping the glue up zone, I mixed about two teaspoons of G-flex. This should be more than enough to coat all the surfaces, pins and holes. 

Starting with one side and coating the pins and holes, spread a thin coat. Then coat the spacer and sandwich together. 
Repeat the layers coating each surface. More is better here than less. 
Everything is pinned, wipe the excess and clamp with low force about 10 lbs. 
After clamping up, wipe the excess epoxy off and check around the fronts of the scales. It's much easier and cleaner to wipe off epoxy now than it is to be scraping it off tomorrow.


The next day after the G-flex was hard, I went on to flattening and squaring the surfaces. There's a lot of material to remove, so I started with a 60 grit and used the work rest to get things as close to 90° as possible.

By squaring the faces it makes it easier to get a uniform shape.

Using the work rest on the grinder I knock off the corners at 45°.

Here you  can see the shape starting to come together. I repeated this with a 120 grit belt.

Once the shape is close to having the desired hand feel, I'll go on the slack part of the belt and essentially rotate the handle while working across the belt.  The slack belt works great with J weight  belts. Shown is a 320 grit. The speed of the belt is important to the quality of the finish. Fast moving belts make a very fine finish. The tachometer says 3491 RPMs.

Some wet sanding with 600 and 1000 grit sand paper.

Here we are just about done the handle.
Pay attention to the areas around the back and bottom of the handle.
Once the handle is nice a silky smooth I take the tape off the blade and do a little clean up. I brush some acetone on the excess epoxy and let it sit for a minute.

Then with a brass "chisel" I go lightly and scrape and remove the epoxy from the steel. As brass is softer than hardened steel it doesn't leave scratches on the blade.
To put the cutting edge on, I a 220 grit in slack belt mode. Holding the blade about 20° to the belt with the belt moving AWAY from the edge I make a few very light, quick passes.
Repeat on the other side. I stand to the other side of the grinder to do this. The belt is always moving away from the cutting edge and my body is well out of the way.