Attaching Scales (The handle)
Caveat - This guide has been put together to show the fundamentals of fitting handles to full tang knives.
Part 1 - Preparation and fitting
First and foremost, lets lay out our components and check all is present, note I have scored the pins and lanyard tube, this is to ensure the glue keys well.
Note: The blade is taped up to prevent scratching during the handle fitting process.
Next we need to prepare, preparation as with most things in life is the secret to success, this is no exception, good preparation will determine if the outcome is successful.
Tip: Check the scales (Handles) are flat, on the side to be fitted to the blade, if in doubt sand the inner surface gently on sandpaper which in turn is resting on a flat surface. Here I have used the band-saw deck.
Note: It is important if using a drill stand to drill the pin / lanyard holes that the sides on the material used for the handles are both flat AND parallel to 'each other', or the drill holes will be at an angle.
Next we need to roughen up all surfaces to be glued, I use 38 grit (The coarsest I could find)
Tip: Did you know roughening up the surface can double the surface area, a real benefit when gluing anything.
Ensure all pins and tube has the leading edge chamfered, this will aid assembly.
Note: Example below is of a brass pin, as it shows up the chamfer more clearly, than the fibre pins we are using for this handle.
All surfaces roughened we now need to select the correct position for the knife and handles in order to mark the holes.
Tip: If you have some nice patterned wood take you time to orient the handle in such a way that the pattern is best utilized. Here I have placed the most patterned area at the back of the handle as the front of the handle on this particular knife is quite thin.
Once the holes are marked on one handle only it is time to drill the holes
Ensure you use the correct size drill, do not use drill sizes too small you may crack the handles driving the pins through.
Tip: 1/4" (Quarter inch) diameter at a glance looks like 6mm, if you drive 1/4" pins into a 6mm hole there is a likelehood the handle material will crack, in any case, it will make assemble using this method very difficult.
It sounds obvious but! Ensure you use a 1/4" drill bit for 1/4" pins and 6mm drill bit for 6mm pins.
Crosscut wood is inherantly weak, until it is bonded to the knife handle.
When using crosscut wood or indeed ANY wood which is cut so the grain length is short (i.e. anglecut) do a dry test assembly and ensure the pins can be pushed in by hand, all the way through the entire assembly, there should be little resistance.
There is no requirement to drive the pins in tight, their needs to be a little room for the glue AND there is a very good chance the wood will split if the pins are driven in.
Whenever possible use a vertical drill set up, it ensures the holes are true.
Drill only one handle at this time.
Now for the clever bit!
Clamp both handles together with the liners (If being used) sandwiched between the handles.
Tip: When using wood or other material with a pattern ensure you orientate both handles the same way round....the wood used for this guide was a matched pair, it would be a shame to get one side reversed and spoil the effect.
With all four layers securely clamped, using the handle already drilled as a pilot hole, drill through all four layers.
Tip: Never attempt to drill through in one motion, back out the drill piece several times to ensure swarf is cleared. If not is can begin to cause excessive heat and burn the holes bigger than the drill.
Tip2: Where possible have a flat sheet of wood or similar under the last layer of the work piece, this will ensure the drill does not split the material upon exit.
Now here is another clever bit....
If you think about it, what is the one place you will not be able to reach easily on knife handles, after they are fitted?
Answer The very front / leading edge!
The front must be ground to shape, sanded and polished, indeed be in a finished state prior to fitting the handles.
To accomplish this we utilize the drills we have just used, to keep the four layers of material we have just drilled in alignment whilst we work the front edge of the handles.
This also allows for the handles to be offered up to the knife precisely so the cut off point for the leading edge can be marked with confidence.
Now the excess material can be ground or cut then ground away.
Tip: Always clamp the pieces together near the front when grinding the leading edge, this will prevent the layers opening slightly and crud getting in-between which will not leave a crisp finish to the edges of each layer.
Now the sides
Tip: move the smaller drill from the front hole to the middle hole, this allows for the sides of the leading edge to be ground to shape without snagging the drill.
And again with a finer grit belt
Once the leading edge has been cut / ground to size it is sanded and polished.
When completed you will nearly be ready for assembly, just one more preparation item and that is to clean all surfaces to be glued.
Note: Manually handling the handles and liners even the pins will leave dirt, even oil from skin on the surfaces, this will impair the glues ability to secure the layers and could allow water or dirt to ingress later.
Wipe all surfaces with a clean cloth and Isopropyl alcohol or meths or acetone or a similar grease removing petroleum based liquid (Ensure you are in a well ventilated area).
Leave to thoroughly dry.
Now you have all your components laid out, clean prepared and ready to fit.
Have a spatula or similar glue spreading implement to hand and also a clean nail, small enough to easily fit into the drill holes in the handles.
Next the glue.
In this example we are using epoxy resin with a 30 minute cure time, in other words it will cure in appro x 30 minutes which form experience means we have around 15 minutes assembly time (pot life).
Measure out the resin in accordance with manufacturer's instructions and mix thoroughly, spend a minute or so mixing, it is critical.
The glue we use dries crystal clear however I am adding a little black colouring to the glue.
Tip: Only use colourings suitable for the glue you are using.
First, using the nail (I am using a trimmed spatula) smear glue 'inside' each of the three holes in both handles.
This ensures the pins / lanyard tube have the best possible chance of being glued all over.
Next coat the pins in glue and insert them into the first handle.
Note: Only push the pins in, flush with the inside surface...not beyond as it will hinder the glue spreading.
Spread glue over the inside surface of the first handle.
Push the pins and lanyard tube in a little further (A few mm only).
This is required so you can push the next layer into place.
Tip: Pushing the pins in too far will only hinder progress as pushing the liner on fully one end only will cause the other holes to be misaligned.
Then spread glue on the INSIDE surface of the liner, (The side being attached to the knife handle) if you get the liner the wrong way around you will have two glue covered surfaces coming together and none between the liner and knife metal.
Push the pins in further and offer up the knife blade against the liner.
Then the next liner, ensuring the glued surface is on the inside and the liner is the correct way around...(Better to re-check)
Then finally attach and press home the last layer, the second handle.
Carefully tap the pins and lanyard tube fully home until they protrude both sides.
Do not use excessive force or the handle may break at this point.
Tip: If the pin or lanyard tube will not drive into place check alignment of the handle material and liners and knife handle, if it is ok extract the pin and try again.
Now we secure the assembly in place with either a vise and clamps or just a few clamps.
Here we are gently clamping the bottom of the handle then attaching clamps along the top.
Tip: do not tighten the vise or clamps too tightly, you are only securing the assembly not trying to compress the assembly, their needs to be a layer of glue in place to successfully secure each layer, squeezing out too much glue will leave a potentially weak assembly.
The next step is important, wipe away any excess glue from the leading edge of the handle.
Tip: slice a wooden spatula / coffee stirrer and wrap with a cloth, this will get right into the corners of the leading edge.
Leave for at least the curing time, if possible leave for twice the curing period to ensure the assembly is firmly glued when the clamps are removed and the assembly is removed from the vise.
Tip: Loosen the clamps AND the vise evenly and a little at a time, if not taking off all the clamps without loosening the vise may put uneven pressure on the assembly causing it to crack.
See Part 2 for shaping and finishing the handle.