Hand Forged "Raindrop" Damascus Steel Full Tang Knife

Hello all and welcome to my very first Instructable.

I recently started forging knife blades and decided to share with you all a small part of my journey. I have forged past quite a few failures and errors to arrive here; at my second attempt at forging my own Damascus steel (My first attempt went.... surprisingly well actually).

I hope that with this Instructable, I can help anyone interested in making their own Damascus knife to bypass the errors and get straight into the fun and enjoyment of creating your very own, one-of-a-kind tool which will hopefully give you many years of practical use and an extreme sense of accomplishment.

NOTE: Throughout this Instructable, there are sections which I don't go into great detail as there simply too much information required to fully explore all options and possibilities (specifically in regard to operating within Fusion 360). I am more than happy to respond to any questions and comments for anyone interested in learning about this project in greater detail. Also note that I am not by any means an accomplished writer and will likely jump from first to third person narratives indiscriminately, use poor grammar, and occasionally misspell words throughout the following paragraphs. For all that are upset by this...I do apologise in advance.

So, without further ado.....

Supplies

Steel - 15N20 (50mm x 50mm x 3.3mm) - 5 off

Steel - 1095 (50mm x 50mm x 4mm) - 5 off

Steel - 52100 (50mm x 80mm x 6mm) - 1 off [Optional]

Steel - Mild (16mm Reinforcing Bar or similar)

PPE (Leather Gloves, Welding Gloves, Welding Face Shield, Safety Glasses, Long Sleeve Shirt, Cotton Drill Pants, Steel Cap Boots, Clear Full Face Helmet, P2 Mask)

Measuring Tape

Scriber

White Marking Pen

Engineers Marking Out Dye

Welders Magnet

Steel cutoff saw (can use angle grinder)

2 hp 2" x 72" Belt Grinder (can use linisher)

Various Grades of Belts (60 grit, 120 grit, 240 grit, 400 grit, 600 grit, 1000 grit)

Bench Vice

Welder (I prefer TIG)

Anvil

4 lb Hammer

Small Gas Forge

Barbecue Lighter

Fully Charged Gas Bottle, Flash Arrestor and Regulator

Hand Steel Wire Brush

Blacksmiths Tongs

Drill Press (can use hand drill)

10mm Drill Bit (cobalt preferred)

Ferric Chloride Solution

CNC Router (Optional but recommended)

PC

Step 1: Designing Knife Within Fusion 360

To design my knives, I first model them up within Fusion 360. This allows me to get a 3-dimensional idea of what the finished product will be without having to use up costly materials. Fusion 360 supplies me with all the tools I could ever need (and then some) to enable me to come up with the perfect knife design. I can play with the shape and colours of the blade, texture, materials and scale. Then when the design is complete, I can output rendered images for printing and uploading to the web.

For this knife design, I primarily used the spline sketch toolset to ensure the blade profile had nice clean smooth lines. I then extruded the blade and handle sections out. For the handle scales, I extruded additional cuts off the top of the from multiple Planes to produce a smooth handle shape which I have learned (by trial and error) feels good in my hand, then I finished them off using the radius tool to round off all the edges and angles.

For this design, I also went back in with a logo design I am currently playing with as a potential 'makers mark' and cut into one of the handle scales as an embossed indentation. The idea with this one was to cut & shape the handle scales on my homemade CNC router (check out the Instructables community for instructions on how to make your own CNC router if you are up for the challenge).

Step 2: Generating G-Code for Use on CNC Router

Perhaps the number one benefit to me in using Fusion 360 is the Manufacture view (change from the Design view to the Manufacture view easily by selecting it from the dropdown box near the top left of the screen). Within this view, I can design the manufacturing process I will be using (in this case CNC milling). It allows me to design the raw material stock, the router tools, the toolpaths and the speeds and feeds, then it will generate the G-Code required for your particular CNC controller so that you can simply open up the code within your CNC machine and run it (with a few additional steps which are a little out of scope for this particular Instructable).

Once in the Manufacture view, I created a Setup which defined the actual dimensions of the raw material I was going to use for the handle scales (recycled thermoplastic sheet in this case) and then defined the particulars of my CNC machine. I also setup the origin of the part at the front/left/top of the stock material (I find it easiest to set up on the CNC). There are many other options within the setup which can be defined but for this project, I will leave them out.

From here I began to generate milling operations. I first generated a 2D Profile operation to cut out the profile of the blade on my CNC router (an MDF template for sizing and marking out). The profile operation, as with almost all the milling operations within Fusion 360, has A LOT of options to allow you to define the exact cutting parameters you need. In this case, I really needed only to ensure I selected the correct tool (4mm flat upcut mill), the correct profile line of the part, and the correct speeds and feeds for the task. I also added in a Drilling operation to drill out the holes for the handle pins.

The handle scales were modeled in Fusion 360 manufacture view in a similar fashion as the blade (of course with a different setup, however with these I required different cutting operations. For the handle scales I used a 3D Adaptive roughing operation with a 6mm round mill to first clear the bulk of the stock material, ensuring that within the Stock to Leave option there was 1mm of stock in both Radial and Axial remaining. I then followed up with a 3D Parallel finishingoperation using a 0.75mm round taper mill which picked up both the handle scale surface and the embossed logo for me. Like the blade profile template, I also added drilling and profile operations to complete the manufacturing design of the handle scales.

The second-to-final step within the manufacture view I use is the Simulation command which allows me to view the cutting operation virtually, in real time. Taking the time to use the simulation option in Fusion 360 has saved me A LOT of errors over the years due to it showing me a what would have been a major problem in real life such as a machine crash or an incorrect toolpath. I STRONGLY recommend using it.

The last step was to Post Process the toolpaths which generated the G-Code that was used by my CNC software (I still use MACH3 but there are a lot of options out there).

Step 3: Cut Knife Handle Scales on CNC Router

The details of this step (machine build, stock choice and hold-down, tool selection, machine operation, etc.) are generally outside the scope of this Instructable. Some hints I will note here however; SAFETY FIRST, so ensure you are wearing PPE and have easy unobstructed access to an e-stop, use a vacuum and dust boot for ease of cleaning, try not to be enthralled by the beauty that is staring mindlessly at a CNC machine as it performs the task, don't forget SAFETY.

The toolpaths which were designed and output as G-code using Fusion 360 were uploaded into my CNC machine and run......I was enthralled....

I removed the parts once they were complete and put them aside for later use.

Step 4: Preparing Raw Steel

And so we get to the blade...

If at all possible, I would recommend you move through steps 4 - 6 as quickly as possible to minimise the likelihood of oxide forming on the layers and causing forge welding issues. Please DO NOT take this as me suggesting you rush the steps. Just plan your time to ensure that you are able to complete these three steps in a single visit to the workshop.

I selected 1095 and 15N20 grades of steel for this blade. These steels are known to have similar forging and heat treating requirements and, when correctly forge welded together, are known to have good contrast after etching which accentuates the damascus pattern. Both steels are high carbon (hardenable) steels and are good blade steels in their own right but 15N20 has a higher nickel content than 1095 which increases the overall toughness of the damascus steel and resists the acid etch.

For this project, I cut 5 x 50mm long pieces of each of the two selected steels out of 50mm flat bar. All ten of the pieces were "cleaned up" on the belt grinder using some 120 grit belts and a welders magnet to hold them. All of the mill scale, marks, grease, etc. have to be sanded off the surfaces of the pieces on both sides to ensure that they will forge weld successfully. Pro Tip: make sure you DO NOT lose track of which steel is which. In this case, I used different thicknesses of each so it was relatively easy to keep track of.

Once all the pieces were "cleaned", I put some clean gloves on and stacked the pieces together in an alternating sequence (Note: some people clean the pieces in acetone before stacking, but I have not done this and have, so far, not had any issues). Align the edges of all the pieces as best as you can and clamp together TIGHTLY!

Step 5: Welding Prepared Steel Into 10 Layered Billet

Once all the pieces are clamped up in the bench vise, I like to completely weld them together to ensure no forge scale can get in between the layers. I have a TIG welder setup in my home workshop and I love using it for knife making, particularly when preparing damascus billets. Any appropriate welding process will do the trick however.

I fully welded three of the four sides, which actually brings us back to why I like to use the TIG. I use no filler rod at all for the welding process; I simply fuse weld the plates together. This has the benefit of not adding additional grades of steel found in the filler rod/wire which are not high carbon steels and are therefore not hardenable. If you use filler rod/wire, this weld steel must be taken off with a grinder or there is a significant risk you will have "soft" steel pockets within your finished blade which will cause all sorts of sharpening and structural integrity issues.

For the fourth side I fuse welded it but left some small openings across all layers (see pic for reference). The theory is that this allows any air (or flux if used) within the layers to escape when forging so that the forge welds can fully "take".

Once fully welded, I welded a length of 16mm "Rebar" onto the side furthest from the side with the openings. This would become a handle for use during the forging process.

Step 6: Forge Welding & Drawing Out 10 Layered Billet

I will just reiterate at this point....SAFETY FIRST! We are now delving into processes and operations which are potentially very dangerous so ensure you follow all regulations and safety protocols relevant to your area. I made my own gas forge for the purpose of making knives (check out the Instructables community for instructions on how to make your own gas forge if you are, again, up for the challenge) but forge kits and pre-built units can be purchased from many suppliers.

I set up the forge and lit it up. I use LPG as the fuel and run it at around 100-120 kPa with full air. I waited for it to heat up a bit then placed the welded billet into the flames. Some people like to add Borax to the billet as a flux but I have seen great results without, and so in this project I did not use it. After about 8-10 minutes, the billet was hot enough to begin forge welding. Please note that in the case of forge welding, the billet MUST be "Orange/Yellow hot", "Red hot" is insufficient for the forge welding process. I take the billet out of the forge and quickly place it on the anvil, keeping a good grip on the rebar handle then, using a 4 pound flat faced hammer, I start striking the billet. The idea (at this stage) is not to hit it with all your might, but to primarily let the hammer do the work and control where you hit it. I start at the base of the billet, near where the rebar handle is attached, and work my way up. This approach progressively "squeezes" the layers together like a ridiculously hard and stupendously hot tube of toothpaste, pushing all the air out of the opening "vents". The billet cools down rapidly once removed from the forge so move quickly to ensure you are able to hammer the entire billet out while it is still orange/yellow hot. Once done place the billet back into the forge to reheat.

I repeated this process four times to ensure the forge welds were set. After this, I reduced the forging temp a bit so that the billet comes out of the forge at a mid to bright red colour, and started hitting the billet with Thor like blows trying to thin out the steel billet to approximately 20mm thick. I also start to rotate the billet onto its side to ensure the edges are straight and also so that the billet "draws out (lengthens)" evenly.

Once the billet was drawn out approximately 100mm long by 60mm wide by 20mm thick, I allowed it to cool down to prepare for cutting.

Step 7: Cutting/Preparing/Welding for 20 Layer Billet

To enable higher layer damascus to be made, the layers are repeatedly forged down, then cut and restacked. This effectively doubles the layer count each time you cut (in half) and restack the forged billet. You can of course forge the layers out more and cut it into thirds or quarters etc. which reduces the time required to increase layers but comes at the cost of increasing the risk of a forge weld failing, turning all your work into scrap metal.

I chose to cut the billet in half and restack, which would take the layer count to twenty. Once the 10 layer billet was cut (as close to exactly in half as possible) one face of each section was cleaned up on the belt grinder. I used a 60 grit belt for this as getting through the forge scale is sometimes....rough going. I also cleaned the edges adjacent to the cleaned face so that I could run a decent fusion weld with the TIG. Once the sections were cleaned, I again clamped them together tightly in the bench vice and fully welded three of the edges together. The fourth edge I welded, leaving small "vent" openings.

Step 8: Forge Welding & Drawing Out 20 Layered Billet

This step is effectively identical to step 6. In the forge until "Orange/Yellow hot", remove from forge, place on anvil and hit with moderate strength blows from bottom to top, repeat 4 times, in the forge to "Bright Red Hot" then draw-out using heavy blows.

The main difference here is that you are now drawing out a twenty layer billet rather than ten.

Once the billet was drawn out to 120mm long x 50mm wide x 15mm thick, I allowed it to cool down ready for another cut and stack.

Step 9: Repeat Steps 7 & 8 Until Required Layer Count Is Achieved

As the title of this section suggests, you can continue to repeat the previous two steps as many times as you like, each cycle doubling the layer count. It is loosely suggested that a "high layer count damascus" has a minimum of 300 layers. A layer count less than 300 is considered "low layer count damascus". It is generally a matter of design specification, preference, time and/or effort as to how many layers you will go to, it should be noted however that some loss of etched contrast is lost in the pattern when getting into extremely high layer counts as the various layers become microscopically thin. Very low layer counts on the other hand, lack the intricate patterning which is what damascus is generally created for.

In this case, I stopped at 40 layers as I was planning to forge weld a solid, mono-steel core into my blade.

Note: If you are not planning to forge weld a mono-steel core (see steps 12 and 13), it would be my recommendation to go to a layer count of approximately 100 to 200 before moving on to the next step as the contrast of the raindrop damascus pattern layers when etched are (in my opinion) most dramatic within this layer count range.

Once my 40 layer billet was drawn out to approximately 160mm long x 50mm wide x 20mm thick, I allowed the billet to cool, however this time, I allowed it to cool down over a long time period by first heating it up and then leaving it inside the hot forge after turning off the gas. I have found that this is a simple and effective way to anneal the steel (form into a "soft" phase or state) ready for machining. This allowed me to carry out the drilling process without excessive effort and many "cooked" drill bits.

Step 10: Drill in Raindrop Pattern

Once at 40 layers, annealed and cool, I randomly drilled various sized holes, approximately 1/3 (6-7mm) of the way through on one side of the billet. This is the functional process which in turn creates the "raindrop" effect for raindrop damascus.

The holes were never any deeper than just the beveled tip of the drill bit. This is necessary to ensure the holes all have tapered walls so that when forging out the billet after drilling, there is less likelyhood of cold-shuts forming (cold-shut is when a "flap" of steel is folded over another forming an air pocket in the steel).

Note: If you are not planning on forge welding in a mono-steel solid core (see steps 12 and 13), both sides of the billet should be drilled rather than just one.

Step 11: Forge Out Drilled Raindrop Holes

Place the drilled billet back into the forge and get up to "Bright Red Hot" forging temp. Then remove the billet from the forge, place hole-side-up on the anvil and beat it mercillessly untill all of the holes are flattened out leaving a flat billet now at approximately 10mm thick.

I learnt a lesson later in the process that I think is better noted here: From this point, forging on the edges of raindrop Damascus does tend to "muddy" the raindrop Damascus pattern as the circular "raindrops" tend to become elongated and misshapen when forged edge ways. In my opinion, it is best to minimise forging in general at this point for a clean raindrop Damascus pattern. I however didn't realise this at the time, so onwards I forged.

Once the billet was forged flat and straightened, I thought I would do what is generally known in the biz as a "sneaky etch". This is where a billet is acid etched to show the pattern at this stage, knowing full well that there will be additional work carried out which will remove the etch. My etch was done for a 5 minute soak in a solution of Ferric Chloride, there are however multiple options on the web for etchants ranging from vinegar and instant coffee through to Citric and HCL acid; trial and error may come into play for you here. Before soaking in the etchant of choice, the face of the billet must be cleaned on the grinder to remove all forge scale.

The damascus pattern on my billet was looking good I thought, although very low layer for raindrop damascus (see pic).

At this point, I again cleaned the edges and one of the faces of the billet on the belt grinder. I then cut the billet in half and removed the rebar handle, forming two damascus sections approximately 80mm long x 50mm wide by 6mm thick, in preparation for the next step.

Step 12: OPTIONAL - Cutting/Preparing/welding 40-1-40 Solid Core Damascus

For this project, the plan was to forge weld 1095/15N20 low layer raindrop Damascus billets either side of a 52100 mono-steel core creating a "sandwich" with Damascus "bread" and mono-steel "filling". This was simply a self-imposed design specification in aid of practicing the art of forge welding; it is completely optional and can be skipped as required. If you don't want a mono-steel core, you can skip to step 14 of this Instructable.

The 52100 steel core came from a section of the outer race of a 300mm OD roller bearing.

I took the 52100 bearing piece, welded a rebar rod handle onto one end and placed it in the forge. I like to bring 52100 up to a slightly lower temp ("Red Hot") for forging as I think it "burns" or decarburizes easier than other steels. This is just my opinion and may not be scientifically backed. Once up to temp, I removed the billet from the forge, placed it on the anvil and "belted it into submission" (forged it flat). I forged it to a billet slightly longer (approx. 100mm), but roughly the same width and thickness as the Damascus sections from the previous step. the purpose of the additional length was to give me a sacrificial section of carbon steel that I could weld my mild steel rebar handle to for the final forge welding process.

Once forged to shape, I cleaned both faces and all edges of the 52100 billet and removed the rebar handle. At the risk of repeating myself......I then stacked the three billets (two Damascus, one mono-steel) together, ensuring the 52100 billet was in the center and that the cleaned faces were placed in the stack face-to-face. After aligning the edges of the stack, I placed it into the bench vice, tightened it up as much as I could, and fuse welded three of the four edges together. On the fourth edge, yet again, I welded it, leaving some small "vent" openings. I then welded on a rebar handle to the 52100 layer furthest from the "vents" (to the longer section of the layer which was stacked over-length as a sacrificial tab).

Step 13: OPTIONAL - Forge Welding & Drawing Out 40-1-40 Solid Core Damascus

This step is somewhat, yet again, effectively identical to step 6. In the forge until "Orange/Yellow hot", remove from forge, place on anvil and hit with moderate strength blows from bottom to top, repeat 4 times, in the forge to "Mid/Bright Red Hot" then draw-out using heavy blows.

In my case, I decided at this point that I would generate a "richer" raindrop pattern by re-drilling the holes either side of the forge welded billet. This, although ultimately producing a nice damascus pattern, did not have the desired effect due to the forging I did to forge out the blade shape in step 14 which "muddied" the raindrop pattern and made it somewhat of a random pattern damascus instead....you live and learn!

I randomly drilled through each side of the billet, only on 2/3 of the faces to save time as the bottom third would either be sacrificed or otherwise hidden by the handle scales anyway. I forged out the holes and ended up with a flattened piece of (40-1-40) layered steel approximately 200mm long x 55mm wide by 5mm thick.

Step 14: Forging Blade to Required Size & Shape

At this stage, I changed out my 4 pound hammer for a much lighter hammer with a rounder face. This allowed me to better control my shaping and forming process.

All of the shaping was done from a "Mid Red Hot" temp.

As I progressed through the shaping process, I regularly checked the blade against the MDF template I had cut out on the CNC earlier to verify that I was moving the steel to the correct places. Slow and steady wins the race here.

Note: While hammering my blade tip down, I actually created a cold-shut (see pic). In this case, the issue was easy to grind out and so caused no problems, but it is important to note that this does happen and that if you miss it, you could potentially be creating a knife blade with a MAJOR structural issue. Ensure you keep checking your steel for defects throughout the whole process.

I forged the blade shape to close, but larger in all directions, than the MDF template. This is known as near-net-shape manufacturing and is summed up in the game as forge thick, grind thin. It is far easier to grind steel with precision than it is to hammer it with precision, although this does come with additional cost of consumables and material wastage so it is best to forge to as close to the final shape as possible.

I again left the heated steel in the forge to cool down and annealed the steel to make the final grinding and drilling processes easier.

Step 15: Finishing Blade 1 (clean, Grind, Drill)

With the blade forged to near-net-shape, and flattened, it was time to make the actual knife.

I first cleaned the faces of the billet on the belt grinder using a 60 grit ceramic belt. Once clean and ground flat, I traced around the MDF template onto the blade with a tungsten tipped scriber. In my case I didn't need to first dye the faces with engineers marking dye, but it does make the profile mark stand out far better, making it easier to grind closely to the lines if required. I placed the blade flat onto the horizontal rest of my belt grinder and closely ground the shape of the blade out, still using 60 grit.

I now used engineers dye on the faces and cutting edge so that I could mark out my bevel lines, plunge line, and the cutting edge centerline. These lines are critical to the quality of the finished blade and so a bit of time should be taken to ensure they are correctly placed.

I now ground my bevels into the blade. There are multiple ways to achieve this using jigs and systems of all kinds and costs, but I generally just freehand grind it on the belt grinder. A lot of care needs to be taken not to go outside the bevel lines, deeper than the cutting edge line, or further than the plunge line. I begin with 60 grit and take a roughly 45 degree grind down to close to the cutting edge line (approx. 0.3mm away), then slowly and gradually rotate the steel, pushing the bevel grind out to the marked line without taking more off towards the cutting edge. Once the grind is close to the lines, I change to a 120 grit belt and grind all surfaces and bevels, refining the roughness and edging closer to the lines (maintain 0.2-0.3mm away from the cutting edge line). Once completed, I now change to a 240 grit belt and repeat. At this stage, the basic bevels should be complete, surfaces should be reasonably smooth (satin finish) and flat.

All that remains before the heat treat is to drill the holes for the handle pins and the lanyard hole as required. Ensure you get the pin hole aligned with the holes in the handle scales as if these are misaligned, you will have issues inserting your pins and will likely not have a clean, refined handle look due to poorly fitted pins.

Step 16: Heat Treatment (Grain Refinement, Quench & Temper)

This step is perhaps the most crucial aspect of a finished knife. Without going into the materials science, crystalline structure and phase changes of steel, this step hardens the steel allowing it to maintain an edge but also ensures that it has the toughness required to survive some impact (dropping, chopping, etc.) without snapping.

To heat treat these steels I placed them in the forge and heated to over the Critical Temperature. The Critical Temp is generally (in my case with 1095, 15N20, 52100) just above 800 degrees Celsius. There are various ways to ensure correct temps ranging from expensive thermostatically controlled ovens to salt piles (salt melting temp is just above 800 deg C); I find it is easiest to check the steel regularly against a magnet. Once the steel is no longer magnetic, it has reached or passed the critical temperature. At this stage I take it out of the forge and place in front of a fan to force it to cool down to a point where you can touch it with your hands without it burning you. I repeat this Grain Refining cycle three times. I find it generally makes a stronger and tougher blade and dramatically decreases the likelihood of the steel warping during the quench.

Once three cycles are completed I prepare a tub of quenching oil by placing a heated piece of scrap steel into the oil to bring the oil up to about 60 degrees Celsius. Again, there are many types of quenching oil but I use a generic brand canola oil and have never had any issues with the steels I work with.

I place the steel into the forge and move it around to ensure the entire blade section is evenly heated to above the critical temperature. I try to leave the tang of the blade "cold" to maintain additional toughness. Once up to temperature, I quickly remove the blade from the forge and place immediately into the oil for 10-15 seconds which hardens the steel. Remove the steel from the oil and check that it is straight. If there is a warp in the blade, you have the option of either re-heating and quenching again (I don't recommend this approach if it can be avoided) or what I do is I place the steel on a slab of hardwood and clamp a thick steel angle section down onto the blade while it is still hot. I leave the blade clamped until it has cooled to ambient temperature (a minimum of 30 mins). This method has proved effective in all but one of the warp situations I have had the pleasure of dealing with.

Once quenched, I straight away grind a section of the face of the steel back to bare metal and place it into a preheated oven at 200 degrees Celsius. I keep the blade in the oven for two hours and then remove it and cool under cold tap water. Once cooled, I place it back into the oven at 200 degrees Celsius for another two hours then remove and cool under tap water again. These cycles temper the steel, decreasing the hardness a little in favour of a large increase in toughness. You will know the temper is good if the raw steel colour has changed to a straw/tan colour. If the colour is a blue or purple colour, you have over tempered it (FAIL! the blade will need re-quenching). If the colour has not changed, you have under tempered it (FAIL! but repairable with a repeat temper cycle at a higher temp).

With the heat treatment complete, we can now go onto the final fit & finish of the knife.

Step 17: Finishing Blade 2 (Clean, Polish, Etch, Mask)

This step is somewhat, yet again, again, effectively identical to step 15 with the difference being in the grits of belt used.

In this step I start at 240 grit and sequentially move through 400 grit, 600 and 1000 grit. This is dependant on the finish you are going for but I find a 1000 grit finish is ideal for the etch process.

Once all surfaces are refined to 1000 grit on the belt grinder, and the blade shape is perfected, I place the blade into the Ferric Chloride solution for 15 minutes. After 15 minutes I removed it from the solution and immediately sprayed Windex onto the blade to counteract the acid, stopping the etching process. I then run it under some boiled water to set the etched pattern in.

Following this, I VERY LIGHTLY sanded the blade using 2000 grit paper on a sanding block. This accentuates the contrast by preferentially sanding only the high, relatively unetched layers, and leaving the lower, darkened layers.

This (thankfully) marks the end of the steel works. I applied a thin layer of blade oil to stop any rust from setting in and prepared to fit my knife together. Note: the oil needs to be removed from the handle area before applying the epoxy to attach the handle scales or the glue will not set correctly.

It is good form to mask up the forward section of the blade at this point to ensure no stray glue from fitting up or accidental scratches are realised at this late stage of the game. I didn't do this step in this case because....I forgot to.

Step 18: Attach Handle Scales to Knife Blade

Because I used the CNC router to pre-form the handle scales to shape, this step was relatively simple. I placed the handle scales against the blade and fed temporary pins through the holes to ensure the shape and alignment was correct. The fit verified, I removed the temporary pins, mixed up some Epoxy (I used West Systems G-Flex in this case but Araldite or any similar epoxy system works just fine).

I applied the epoxy to both the steel and the handle scales, following the epoxy suppliers instructions. I then loosely clamped the scales to the blade and fitted the final pins (In this case I used brass Gulso bolts) and tightened them up.

I left the knife clamped up for approximately 24 hours before removing the clamps.

Step 19: Finish Knife (fine Grit Sand, Sharpen, Oil)

All that was left at this stage was to give the handle a high grit sand, sharpen the cutting edge, and reapply a coat of blade oil.

I used a 400 grit belt on the belt grinder to grind a sharp edge onto the blade (I ground it to approximately a 20 degree angle each side). Take EXTREME care to run the belt slow, quench in cold water often, and to not leave the belt in the same spot for too long. If the blade is heated up too much, it will ruin the temper of the blade causing it to revert to a "soft" phase. This is obvious when it happens as the steel take on a localised blue/purple hue. The knife blade is particularly susceptible to overheating right at the tip of the blade. You have been warned!

I then moved on to sharpening stones at 1000 grit, 3000 grit and finally 8000 grit. Last of all, I ran the cutting edge over a leather strop with polishing compound.

A final hand sand over the handle only with 1000 grit paper and application of a thin coat of blade oil and my first raindrop Damascus knife was complete.

I tested the blade edge first against some paper, which it sliced through with surgical ease, and then on some carrots for dinner. Mission successful!

Step 20: Enjoy Your Creation!

....and that's that.

I have yet to make a sheath for this one; i'm thinking stained leather. When I come up with a design for it, I will create another Instructable showing how this works out.

Thanks for reading and I hope you are successful in making your own knife based on this Instructable. If you do, I would love to see the final product.