Saturday, August 31, 2013

BC1 - MAKING A STOUT BUSHCRAFT KNIFE

BUSHCRAFT KNIFE


I've always had a thing for sharp things from kitchen knives to chisels. I have also had a keen interest in bushcraft since going camping with my family as a kid. Combining these two things with some of my famous DIYness, I decided to embark on a self taught lesson in knife making. I hope to make this more of a photo heavy how-to.


Since I do not have a forge made yet, I figured that the stock removal method of would work best for an intial effort. I found Canadian Knifemaker's Supplies here in Alberta and ordered some stock. I chose 154CM (more on this choice later) as it is tough and stainless. I wanted my bushcraft knife, which I have dubbed BC1, to be about 8 or 9 inches long (overall) and possess a thick, indestructable blade.


Above is  my first finished knife.

The steel arrived yesterday. One piece of 3/16" x 1-1/2"x8" and one 5/32"x1-1/2x9". Going forward I will refer to these by their decimal equivalents: 0.187 and 0.156 respectively.

 The 8" piece was actually about .25" longer, so I planned my profile with this in mind. The price of this stock was just over $2 an inch, so about $18 to $19 a slab. Shipping via courier as extra.

PROFILE


Profiling is the art of transferring an idea to the steel. I sketched a basic shape on back of an envelope, then redrew it on some printer paper. Once I had the basic idea together I trued it a little and traced it to another sheet.
After carefully cutting out the profile with scissors, I glued it to a piece of hi-ply 1/4" plywood using regular carpenter's glue. Brush the glue on thinly and walk around the edges to ensure that the paper sticks down good.

I then worked the scroll saw and belt sander to get a shape that was close to what I wanted. It should be noted that the template should be a tiny bit undersized so that when you trace around it, you get very close to the desired size.


A few photos can walk us through the process.











REMOVING STOCK


Once traced out with permanent marker, it's hacksaw time! This steel is incredibly tough. I was lucky to have a new, very good hacksaw blade. This is one thing you don't want to cheap-out on. Clamp it in the vice and give it a go. Slow steady strokes, about 2 per second works best.


 154CM is surprisingly hard to cut.
 This is after almost 10 minutes of sawing.
 Notching out the hard to remove areas.
As you can see this is a bit-by-bit operation. Some sawing this way and that to take triangular pieces out of the stock. Occasionally, I would add a drop of oil to the saw blade. Once close, I used a bench grinder to get the shape closer to the line. Be sure to have some water handy to cool the piece when grinding. Go slow and make many passes.




Rough profile achieved and this puppy is ready for the sander. Total time with hacksaw and grinder, 3 hours. As this stock was 1/4" longer I altered the shape of the handle slightly and used up some of that extra to create a longer handle. If future stock pieces are exactly 8" long, we will follow the template.

Once the stock is exactly how I want it, I will trace this back to paper for the record.



Friday, August 30, 2013

BC1 - HANDLE PINS & LANYARD HOLE

HANDLE PINS & LANYARD HOLE

Before I get to the cutting edge I will explain what I am doing for the brass handle pins. I wanted the lanyard hole to be about the same diameter as the handle pins, yet this hole has to accommodate 550 parachute cord which is typically 0.125 (1/8") in diameter.

An immediate solution is to precisely drill out a small piece of .25 brass rod to 0.187 (3/16"). With a little work from a tiny rat-tail file this should be ample room for a piece of para cord to slip through.



I drilled a hole just a shade under 0.25" into a wooden block and tapped a piece of brass rod in, about 1.25" into the hole. This, along with the drill press would keep the hole as vertical as possible. The bit size for boring out the brass was 0.1875". This seems to have worked better than I thought it would.


Showing brass round stock and drilled lanyard hole liner.
 






Double checking the diameter before committing to the holes.
After checking the stock with a caliper, I then drilled the holes in the knife stock. Recommended steps:
1 - Centre punch
2 - Drill pilot hole
3 - Drill to 0.25".

Set the drill press to the lowest speed and be sure to add a drop of oil to each hole before drilling.



Thursday, August 29, 2013

BC1 - CUTTING EDGE

 CUTTING EDGE

To get the ricasso (the unsharpened part on the bottom of the blade where the cutting edge starts) correct, I started the edge grinding with a file and a piece of wood for a guide, this way when I go to the sander, there will be a good reference to start each pass. Start the edge on both sides of the stock.




All clamped down. With a mill/bastard file I started the edge. Just enough to get a good idea of where it will be. In following the Ray Mear's Woodlore style, the ricasso to edge junction is angled similar to the handle line.





 









The bevel I chose is 15 degrees (each side). This varies from the typical 11 to 12.5 degree "Scandi" bevel, but after viewing what the belly would look like and taking into considering the thickness of the stock, 15 degrees will be fine. It will allow for the BC1 to be a log splitter with suitable baton in hand.


As a guide, a piece of 3/4" ply cut on the mitre saw does the trick.


Some serious slow-going work begins. Keep the water pot handy as the blade will warm. After each pass I cooled the tip.







 


 After some time with 50 grit sanding belt on the machine blade is looking good!

Do not attempt to "sharpen" the edge at this time. There is a risk that a sharpened edge with warp with heat treatment, also it is an unnecessary handling risk. E.g. you don't want to cut yourself! I left the edge about 0.0625" (1/16")

There will be plenty of shaping and honing after heat treatment.








Wednesday, August 28, 2013

BC1 - ROUGH HANDLE

ROUGH HANDLE


This evening I tossed a piece of scrap teak in the thickness planer and spotted some of those "quarter sawn fleks" of light thrown off. This piece came off of an old gas BBQ that sat outside for years. You remember the ones with the little side tables made of wood? 

I ripped the piece and selected two sections for the scales. My initial rip on the bandsaw didn't go too well and I ended up finishing the rip in the tablesaw with a thin kerf blade.

 After ripping, I ran the long pieces through the thickness planer and then shortened with the compound mitre saw.













Out of thickness planer.

In order to align the scales and keep them in place for shaping, I am going to use dowel that I can drill out afterwards.  The trick was to carefully align the front angles as precisely as possible, while only being able to drill one scale at a time. Patience! I trimmed some short pieces of poplar dowel and tapped them in to hold everything together.

I will be drilling these pins out after the shape is ready for fine sanding. Remember the knife has to be heat treated and polished before the handle scales can be attached permanently.

Once the tang was sandwiched, I went to work on the belt and disc sander to bring the scales closer to the shape of the metal.

 Trim saw for getting the pins close.







Belt sander to chow down on the pins.








For the curves I used a small drill type sanding drum in the drill press. 1" drum with 80 grit.
 The shape is close for now, but needs to have the thickness worked out.


A note on the handle shape. I wanted the front of the handle to be similar to the ricasso line, but not exactly parallel. I was looking at the lines on my car the other day and thought of a handle shape.












Next I'll shape the handle with a rasp and sanding papers.

Tuesday, August 27, 2013

BC1 - HANDLE SHAPING & PREVIEW

HANDLE SHAPING & PREVIEW

The handle slabs are course and need some shaping and sanding. I used the 1" sanding drum with 80 grit to work both sides down to the approximate shape. Periodically I gripped the knife to get a feel where my fingers will go and how the knife feels overall.  
 The scales will come to meet the steel edge so starting with the beveling on top and bottom first made sense.
After about 45 minutes on the drum, I hit it with some 150 grit sand paper. If at this stage I don't like it, it's easy enough to abort this handle and start on another one.
 One wipe of tung oil and I knew this was going to look fine!

The flecking shows well with tung oil. I now need to drill out the poplar pins and remove the scales as the blade still needs more work.


 Very carefully drill out the pins. I used a 7/32" bit that was a shade smaller than the pins. On the drill press, precisely centre the bit on the pin and drill in the thickness of the scale only. I did this on one side. The separation was easy and I used some pliers to pull the pins from the other half.
 Scales removed. This is NOT the final finishing on the handle.The handle will be epoxied into place, brass pins inserted, ground and flared. So lots of work left for later.

Monday, August 26, 2013

BC1 - PRE-FORGE POLISHING

PRE-FORGE POLISHING

Before the steel hits the forge, we should polish it as best as possible. Once hardened and tempered it will be much more difficult to work. Starting to polish the blade. Clamp the butt end of the tang down and start with 80 grit sandpaper on a wooden block. Long straight strokes along the blade. Don't worry about the sanding the tang as it will be hidden.

80 grit after a few minutes.
Next step will be 100 grit, then 220 until any mill scale or surface inclusions are nearly gone.












Another reason not to polish the faces of the tang is that the epoxy will need a good place to stick. Typically, before the scales are epoxied and clamped down, it's a good practice to grind some marks or drill additional holes in the steel. This will give some areas for the adhesive to grab on to.

After heat treatment, this blade will be considerably more difficult to polish, so doing more now saves some time later.

In the future I will do this with the belt sander. However rewarding it was a LOT of work. 


 Soon we are going to need to get the forge and quench tank setup. Shopping list: Firebricks, fireproof mortar, oil etc. :-)

See how I made my 

















Sunday, August 25, 2013

BC1 - HARDENING

HARDENING THE KNIFE

Hardening high-carbon knife steel is essentially heating the blade to red hot and quickly cooling it (known as quenching) in water or oil. In some cases salt or air can be the cooling medium. For the particular steel I am using, a 30 minute soak at about 1000°C (yellow hot) then an oil quench is recommended by the manufacturer.

I started by preparing the area; getting the forge and quench tank setup, grabbing my welding gloves, vice-grips, safety glasses and so on. The oil can be vegetable oil, motor oil, olive oil, etc. I happened to have some motor oil kicking around so that is what I used. The smoke from an edible oil will be less offensive than motor oil, so after my first time, I will recommend some el-cheapo cooking oil.

 Inside the forge, I needed to move the blade around and get as much as I could a nice even yellow colour. The magnet is on top of the forge (see picture above) so I can check a carbon steel's magnetic properties before quenching.

When the steel is a pale yellow colour, maintain this colour as best you can for 30 minutes. If this were a carbon steel blade, we'd get it red hot and apply it to the magnet. If it is non-magnetic, give it one more shot of heat, say 10 seconds and then dive it into the quench tank.


When the hot steel is plunged into the oil, it takes a few seconds for the vibrations in the steel to stop. I give it a gentle stir or sway back and forth for about 15 seconds.

Once quenched, the blade will look burnt. That's normal. If you want to repeat the process again you can. I repeated this heating and quenching process three times, each time checking with the magnet before quenching.

The steel is now very hard now, but also very brittle. 


When the blade is cool to touch, we need to clean it up for tempering. Tempering is a softening process that reduces the brittleness and allows for sharpening the cutting edge.

This is the oil that was baked on to the blade during quenches.
 Clean up the faces with 220 grit sand paper.







Clean up of the tang edges with 220 grit.

















Once cleaned up, we need to temper in an oven at 230 to 250°C (450 to 475°F). The heat cycles are 230°C for two hours, then cool to room temperature, then a second soak at 230°C for two hours. The steel should come to a yellow straw colour.

Saturday, August 24, 2013

BC1 - TEMPERING

 TEMPERING



Tempering or "drawing" the steel involves heating it to around  250°C for an hour or two. The steel takes on a yellowish hue. When the tempering is done the blade will be hard yet flexible and fairly easy to sharpen.

For my heat source I used a counter-top oven that I setup outside of my garage. (It was going to be a hot one today and having the big oven in the house on for several hours at near full heat didn't sound appealing.) I placed the over thermometer inside and set the blade on a block of steel.

I heated up the oven to about 250°C (475°F) for two hours, then let it cool. Once cooled to about 25°C, I repeated this cycle. Crucible recommends 2 soaks of 2 hours at 204 to 425°C. This temperature impacts the overall hardness. The aim is to get the steel hardness between 59 and 62 Rockwell C.

Different types of steels have different recommended tempering schemes.
 The blade definitely takes on a yellowish tint, almost golden. Very nice, but I will be polishing that all off shortly.




Tuesday, August 20, 2013

BC1 - POLISHING


POLISHING

Polishing is one of those time consuming tasks where patience pays off.  The process is to start with some 150 grit sand paper work the surface evenly until no scratches are visible. Then move up to 220, then to 320, then 400 and so on, each finer grit is taking out the previous grit's scratches.



Sandpaper sheets are cheap and effective abrasives for polishing a knife. I buy the bulk packs of commonly used sizes ranging from 80 grit to 600 grit. I cut the sheets into 6 pieces like shown. I then have a suitably sized block of wood to hold the paper flat while sanding.


It's not uncommon to use a whole sheet on a blade. You'll feel when the sandpaper stops "cutting"  or "dragging" like a new piece. Toss it out and grab another piece. A squirt bottle with water comes in handy as does a rag so you can check your work.


All of the sand papers use water to remove the debris and keep the metal surface cool. I clamp the blade to the bench and work longways over the blade, adding water periodically.

Note that I am not overly concerned with polishing the area that will be hidden by the handle slabs.



It's still not complete at 600 grit, but the satin finish looks pretty good and there are no noticeable scratches or scars.


Once we make it to 600 grit, we can start with the polishing compounds on the polishing wheel.



Although it sounds like an oxymoron, black rouge is an abrasive with emory particles. It is for course polishing. Follow this with either red rouge or green rouge for stainless steel. Since 154CM is considered a stainless steel, I will move to the green rouge on the buffing wheel.

Word is that Mother's Mag & Aluminum Polish works really well on stainless. I may try some and report back.



Before I get to the final buffing, I want to shape the cutting edge bevel. I used a Gatco honing system, which seems to be hit or miss as far as holding a good angle. It is supposed to hold the angle of the stones consistent, but there is sufficient play in the plastic to cause the stone to rock a degree or two. I may have to develop a proper, sturdy jig for this


I am going to test the etching process today. I will do it on the tang under the handles. I placed a scale on and marked with a pencil to tell me where the handle will start. Then I taped the blade end off on the pencil line.

Next is the mask and etching test.

UPDATE: The knife fell straight, tip down on to the concrete floor in my garage suffering a chip on the tip. I will have to re-grind to get it into shape. Much more work than expected.