Friday, July 24, 2015

KN16 PETTY 160mm - LAYOUT & PROFILE

I am going to make a smaller Japanese kitchen knife called a Petty. It will have a traditional handle "wa" and be about 11 inches (270mm) long overall. The steel is my old standby AEB-L stainless from Uddeholm in Sweden. My stock is 0.130" x 1-1/2" x 9 inches long.
After tracing the KN16 pattern on the steel I cut with the band saw.
Cutting just outside the line. In the curve here I make a series of cuts to get the curve close. These slots will be cut or ground out after.
On to the grinder with a 60 grit to bring the shape back to the lines.
Checking the shoulder for squareness to the spine of the blade. This will present the wa handle in a line straight to the spine.
After some rough grinding on the primary bevel I will tidy this up for heat treatment.











Lakeside hand sanding. This is what lawn chairs are made for!









KN16 PETTY 160mm - WA HANDLE

For this Petty I am making a wa. I like the geometry and balance of the octagonal wa. Here I have assembled the materials and drilled pilot holes in their centres.
The pieces are 1/4" copper, ebony, white turquoise gemstone composite, black fibre space and stabilized maple burl. All of the pieces except the copper are drilled for 7/16" wooden dowel.

The copper will hopefully add a little bit of weight to the centre of the knife.
Once the dowel is cut to length (short is better than too long) I epoxied and clamped all the pieces together.
Once the epoxy is set, I start to shape the handle on the belt sander. The large flat area is easy to work on. I am using an 80 grit aluminum oxide belt here.
After the block is square, that is right angled corners, I scribbed markings to make it easier to see the 45° angles that will be ground next.
Here I am taking the points off at 45°. Dipping in water frequently as the copper can really heat up. Even pressure and steady hands make this part look good. I do the front ferrule part, then the back of the handle. Then I feather them together in the middle.

Here is the wa after about 30 minutes of sanding on the belt sander.






My second wa!

KN16 PETTY 160mm - HEAT TREATMENT

A little bit if finish sanding to remove any obvious scratches.
Here I am going to apply the Condursal Z1100 protective paint.
This prevents oxygen from reacting with the surface of the steel at high temperatures/
Hang to dry for an hour or so.
I put the blade in the oven at 650°C and ramped up to 1060°C for a 15 minute soak.
Out of the oven and quickly going from bright yellow to red in colour.
Sandwiched between two copper plates and a little blow of compressed air.
I had the tempering oven preheated to 185°C (365°F). Two hours and cooled to room temperature. Then another two hour run at the same temperature. This should be close to Rockwell 60C hardness.

KN16 PETTY 160mm - FINISHING & HANDLE WORK

Here I am doing some wet sanding at 220 grit. The strokes are even and all move the direction, away from the tang. This is to avoid those little Js and loops from stroking back and forth.
This is a satin 400 grit rub. Ready for maker's mark and wrapping up.
My stencil goes on with regular blue masking tape. I applied electrolyte to the pad and etched for 25 seconds and marked for 15 seconds.
I also have added the steel type to the right side neck.
Ready for taping up.
Marking the tang on to the ferrule. Centred and centred.
Using the long aircraft style bits to drill into the handle.
Making a series of holes with a 7/64" bit in the drill press.
When it comes to jigging out the holes, this comes in really handy. It's a good old jig saw blade installed into a small set of locking pliers.
Here the fitting is almost complete. Just a little needle file work left to do.
Mixing up a batch of Acraglas. 10 ml for this one as the interior of the handle needs to be full. After, I realized that 5 ml would have worked as I had a lot of extra squeeze out.
Note I also taped off the ferrule area. You don't to be getting epoxy on there if you don't have to. It means more clean up. Waiting until tomorrow to see how it all cleans up!

KN16 PETTY 160mm - SAYA



For the saya I found some pieces of Eastern maple from an old pallet. It had a little section of interesting grain so I planed it with the thickness planer.
I set the fence on the table saw to rip about 3 mm (1/8").
Three pieces are needed. One centre and the two outsides. I traced the blade shape on to the centre lamination and cut out on the band saw.
Now to glue the centre to the right. Here I used indoor/outdoor carpenter's glue. Even pressure is required. Extra glue can squeeze out, that's not a problem. Just wipe it off with a damp cloth.
Once dried, I trace a line about 5 mm (3/16") outside of the pocket. Then cut this shape with the band saw.
Now to glue the cut out to the left panel. Same glue is used here. After this dries well, cut the left panel to match. Now we have all three laminations the same basic shape. Sand a little and drill the saya pin hole. I went with 3/16" dowel.
Rubbed some mineral oil in for deep protection.
After an application of tung oil. The tung oil hardens and is buffed with some fine steel wool.


Tuesday, July 7, 2015

KN12 PETTY 205mm - LAYOUT & INITIAL GRIND

I am going to make a kitchen knife style in the Japanese gyuto (chef's knife) style. It will feature a wa, the traditional handle. 

For this knife I used the KN12 pattern, which is an 8" gyuto wa. I glued the printed paper on to a piece of 1/4" plywood with carpenter's glue.
Cut the shape out on the bandsaw and cleaned up the edges with a belt sander.
I will be applying this to a 1-1/2" piece of  154CM steel, so this is more of a petty knife than a proper gyuto.
With the bandsaw, I cut close to the line.

In a few minutes the rough profile is done.
On the belt grinder with a 60 grit ceramic belt I take the shape back to the line.


Now the shape is very close, I'll clean up the faces. It's super convenient to use the 4"x"36" belt sander with an 80 grit aluminum oxide belt.
You can see the shape is similar, but the petty knife is not as deep as the gyuto.