Friday, September 26, 2014

KN7-2 CHEF'S KNIFE COMPOSITE HANDLE PT. 1

With the second KN7 I wanted to lighten things up a lot. The first KN7 weighed in at a whopping 300 grams which is going to be tiring to wield for hours on end. With this build I envisioned G10 and stabilized burl wood, but I wanted more than the basic bolster handle scheme. Having thought about it some, I come up with an interesting idea that will take some planning to execute.

I made an oval pattern about 115 x 65mm. See the Ovals Pattern PDF file here. I printed on paper and glued onto some lightweight plywood.
Moving the pattern around I found a sweet spot where the curves look good and the pin holes will work for a three piece scale.
 I placed the oval on and trace the lines for reference.
I cut some 1/4" black G10 on the band saw. Four pieces are needed. Two for the front bolsters and two for the rear bolsters. I will start with the rear bolster pieces.

It's very important to wear goggles and a respirator when working with G10. The glass in it is irritating.
These start as about 1-1/4" squares and get shaped using the oval as a guide. Band saw and belt sander until the shape is a good match.







With two pieces shaped, they are checked against each other. An easy way to do this is get them close, then clamp them together with vise grips and finish the shaping on the belt sander while they are together.

Clamp on piece to the tang and drill to 3/16". Pin with a wooden dowel and clamp the second one to match. Remove the dowel and drill right through the first piece and the tang into the second piece. I use this same technique for matching scales. 

Once the two rear bolster pieces are temporarily pinned with wooden doweling, clamp and start shaping the wood section to match the curve. Disk sander works good here. Keep checking fit and adjusting.
Now you can use the oval to mark the bolster side of the wood scale piece to create the ellipse. Pin with dowel and repeat for the other side.






See Part 2 for more.


KN7-2 CHEF'S KNIFE COMPOSITE HANDLE PT. 2

Part 2: Continuing with the multipart scales for the KN7-2.


Using dowel as pins I fit the second Amboyna burl scale to the rear bolster piece.
 Once drilled I remove from the tang and shape the fronts to match on the disk sander.
Now it's on to rough shaping the bolster, also black G10 and drilling and temporarily pinning. Testing the fit here is critical as the next fitting will be with epoxy and there is little room for error when the clock is ticking.
Removed from the tang, the two bolster pieces are pinned and sanded while a single unit. Focus here is on the fronts as these are extremely difficult to sand and polish while on the knife.
 
I cut and sanded all the pins about 3/4" long. These are brass 3/16" and brass 1/8". It's prudent to sand the ends a little bit so they go in easier and don't tear out when moving through the other side.   


Being frugal, I used a syringe and mixed a right-sized batch of Acraglas for this application. This amounted to about 4 ml of epoxy, which is about a teaspoon.




First the bolsters get pinned on, then the mid-section and finally the rear bolster pieces.
All gooped up and clamped with vise grips. Note I used some wipes to pad the clamps. Once cured the Acraglas will rip the leathers off my grips.




KN7-2 CHEF'S KNIFE HANDLE FINISHING

I left the Acraglass overnight to cure. Once set, it was a job to sand everything back to some basic shape where the sides are parallel and the shape matches the tang..

This is quite crude at this stage. I am using the 4x36 belt sander with 80 grit belt/
To get inside the curves, a half-round file is handy. This moves material quickly, but we have to be careful when getting close to the steel as it will scratch heavily.
The profile is done. Now for some 150 grit sand paper.
 Moving over to 220 grit with some window cleaner as lubricant.
 Some more mild shaping and work with the 340 grit.











Tuesday, September 23, 2014

KN7 CHEF'S KNIFE - STACK SHEATH

As one of the big chef's knives was for a culinary arts student who would be taking it to school and home and occasional catering work, a need for some protection was in order. I basic stack sheath seemed like a logical solution. Here is how I went about making it.


I started with a piece of 9-10 oz. vegetable tanned leather and traced the basic blade shape on to the rough side. I trace outside the blade by about 5/16" or about 9mm. This will be enough for a welt and stitching.
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I extended a strap off about 45° that will have a snap to keep the blade secure. This strap is about 3 inches long. Longer is better at this point as you can always cut it shorter later, but it's really hard to extend!

I use a brand new utility blade in the knife and it cuts leather very well.
Trace the blade portion of the back onto the smooth side of a piece of the same leather. This will be smooth side up remember.
Cut out with the utility knife.
Now to make the welt. I traced the back piece onto a scrap piece of 7 oz. leather. This leather will determine the fit of the blade inside, so try and match the leather thickness to the blade thickness. About 1/8" for this knife.
The welt is also about 5/16" wide and follows the shape of the blade.
Now apply contact cement (or barge cement) to the back and welt.
I did some very basic edge using my custom branch leather stamps that I made in the DIY Leather Stamps page. I think here we don't want anything too fancy as we want this easy to clean.
The welt is attached to the base. I test fitted the snap. Once happy with the location I used a leather punch and pressed the snap pieces together.





On the inside of the top I put some contact cement and prepared a small piece of felt. This will prevent the snap from scratching the blade in its way in and out of the sheath. I also put some contact cement around all the edges but the opening.




 
 Once the cement has set, carefully place the top on. The cement will stick right away and you don't have much opportunity to move the piece. I started at the tip and worked back until full contact was made.


Walk around the outside with a compass and very lightly pencil a mark about 3/16" in from the edge. This will be where the stitching goes.
With a guide line in place, I use the over-stitch wheel to mark the holes. I think my wheel is a 4mm and I end up using every other mark as a hole.
This is the slow part. With the drill press and 1/16" bit, drill each hole. Do this slowly and carefully. Do not force the bit, let it drill its own hole.
Some people reverse this and the above step, but I find it's easier to make the holes nice and straight before grooving. The groover takes a millimetre of leather off so the stitches have a place to sit nice and low profile.





I spool off 8 times the length of edging in synthetic sinew. In the stitching pony I go around alternating every other hole.







Hopefully this stitch diagram illustrates how the hand stitch looks from a profile view.

First pass of stitching is done.
Adding medium brown stain. I mixed a little bit of USMC black and walked around the edges to give it a sunburst effect.
Once dried a few hours, I popped a hole for the button part of the snap in the strap. As the leather is pretty thick here I had to press it down to get a good bite with the rivet.
This is the basic product. I will run the second stitch with black artificial sinew through every other hole to create a light/dark stitch pattern.

An application of antique finish and some burnishing on the edges will really add to that worn in look and feel.



 Nice and snug in its new home!