Wednesday, January 21, 2015

DH1 - 8" TWINS - THE SEPARATION

My first knife project of 2015 will be two little DH1s. I have a piece of 1/8" 154CM that's 2" by 8" long. I can cleave the one piece into two knives if I am very careful. If all works well, these will be third and fourth DH1s I've made.

Here's a sneak peek of what they turned out like:







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I traced the shape on the steel with the DH1 7.875" pattern. You'll see there is little room for error. The blade will take up about 1/16" if I am right between the lines.
Sporting a 1/16" cobalt bit I drill a series of holes between the shapes.
Now connect the dots with a hacksaw. Note that the blade needs to be turned 90° as we get into the middle region.
 Not pretty, but separated. Now to clean them up.
 On the grinder with a 60 grit belt. Remove excess stock back to the lines. This is why it's called 'stock removal'!
 One done. Repeat the process for the other brother.
 Two done.
I used a spindle sander with a 1/2" drum to get the inside curve looking smooth.
Once they are profiled close to the pattern, I mark them A and B.
On to the sander for some surface smoothing.









 Now that they are separate, I will work on them one at a time up to heat treatment.

DH1 - 3 & 4 SHAPING

After the separation, the twins were ground and finished as individuals. This is the during the rough grinding on the belt grinder.
Cleaning up the bevel with some wet sanding.

  This is what it looks like after hand sanding.







Now we need to lay out where the handle components will go so we know where to put the pin holes in the tang. Here I'll be using three 1/8" pins and one 3/16" pin in the middle of the scale with two 1/8" pins off that middle pin on an angular line.

Once the pin holes are in, some mass removal holes to lighten up the back end of the knife.
Looks like Swiss cheese at this point, but it's feeling a little heave on the blade side. When the scales are attached it should be very close to balanced.

Foil wrapping. I create an envelope out of stainless steel.
The envelope is sealed by folding and pressing the edges.
Ready to take out of the oven after 20 minutes of 1065°C.
Tiny bit hot in there. I used good fire gloves and set of long nose pliers.
This is the first knife after coming out. You can see it's still very hot. The outline is visible through the foil wrap.
Pressing the knife between two 1/2" thick copper plates. This sucks the heat out the steel in a hurry. In less than a minute it's cool enough to handle with bare hands.
This is what the DH1-3 looks like when opening the foil.


The two are together again and will go into the tempering oven at 200°C (~400°F) for two hours. Then cooled, then another two hours at 200°C.








DH1 - 3 COMPOSITE SCALES


To layout the scales, again I used the oval as I did on the knife itself.  I've put some marks at various places around the oval to allow me to align it in a repeatable fashion.

I'll use some scraps of African Blackwood for the bolster pieces.
Once I have one shaped close to the line, I clamp a second piece and shape them together. Identify the pieces as L or R with pencil so you don't get them mixed up.
The stabilized yellow birch scale pieces are shaped to fit inside the bolster curve. To do this, place the bolster piece on the scale and mark the curve. Shape close to the line on the disc sander, then clamp it to the bench and use a file or some 220 grit sandpaper and a block. Try to keep the block perpendicular to the scale face.
Here they are fairly closely matched. 
I am going to rough up some 0.02" aluminum with 60 grit sandpaper and cut oversize with tin snips. I will join these with epoxy and grind off the excess.
Here is a simple clamping jig to hold the pieces while the epoxy sets. I lined the bed with waxed paper. Epoxy has a hard time sticking to waxed paper.
I have clamped the scale piece in and I am applying the epoxy. Apply epoxy to every mating surface, wood and aluminum.
With a few clamps, apply slight end pressure. You don't want to squeeze all the epoxy out.
This is what it looks like after popping one out of the jig. Epoxy doesn't stick to the waxed paper. Ya!
Grind off any excess aluminum and epoxy. Repeat the process for the other scale. These will be pinned and epoxied to the tang after we shape the fronts of the bolster area.

Tuesday, January 20, 2015

DH1 - 3 SCALE WORK PART 1


On most builds the scales get drilled and roughed pretty quickly and don't get much attention. In this build, I wanted to step you through the process. This is how I do scales that need to line up very closely.

Start by laying out the L & R scales and finding that sweet placement. For this knife, I have the aluminum strip to act as a guide as it stands out between the two woods.
After marking the line of the aluminum strip or bolster-scale curve on to the knife, use this mark to align the scale pieces. Trace the tang shape and leave an extra 1/8" or so around the outside so we can sand it down perfectly later.
Over on the band saw, cut close to, but just outside the line.
Align and clamp the first scale. It doesn't matter if it's L or R. I used some vise-grips and my handy drill press block #3.  Drill to match the tang holes for the pins. For this knife they are 1/8" and 1/4".
Another shot of how the vise-grip and block hold and support the two pieces while drilling. You don't want anything to slip or go off kilter here. Nice and perpendicular holes.
The holes in one scale are drilled.
Now, I cut some 1/8" wooden dowel. Each piece is about 1" long.  Press the wooden pins through the scale and into the tang, but stop there.

Now the big alignment. Make 100% sure the second scale is lined up. In this case the aluminum strips have to perfectly match on the top and bottom sides. Clamp firmly with the vise-grips.
Remove one pin and drill through the first scale, through then tang and then all the way through the second scale. You can press the pin through again if you like, but the clamping force is holding everything together.
Repeat until all the pin holes are drilled. Press the wooden pins all the way through. Lightly tap them in if needed.
Now we can see the scales and how everything is going to line up. Inspect carefully and visualize where the tang sits inside the two scales.
Remove the pins and remove the tang. Using the same wooden pins, fit the two scales together. You can take some material off with the grinder as long as you don't go too far and into the scale where the tang is going to be.
As the two pieces are pinned, we can shape them together and match the fronts. Special care is given to the fronts of the scales as we won't be able to get into that area once it's all together. The ricasso of the blade will be right there.




 Get the fronts of the scales smooth and polished.



From here we'll have to shape the handle when it's all epoxied up.