Making Custom Wooden Scales for 91mm Victorinox SAK, Using a CNC Router

This is the first project that I documented in the form of a video and published on my YouTube channel and fter more than two years, I can say that making the scales for a SAK myself was a great move, they are much more durable than the original ones (tested on many falls), the knife seems more solid and looks totally awesome!

I received the Victorinox as a gift from my wife and immediately became the most important element of my EDC, I used it and I still use it several times a day. Frequent use causes equally frequent falls, and these cause damage, the scales take up most of the hits, and the original ones, made of plastic, quickly began to get loose and crack. Problems with the store where I ordered new scales caused that I decided to make them myself from wood and learn something.

Materials:

• piece of hard and solid wood
• boiled linseed oil
• hard varnish for wood or CA glue

Tools:

• CNC milling machine
• 3,175 mm (1/8 in) and 1,4 mm milling bit
• belt sander or sandpaper and a lot of patience
• precision knife
• small files and sandpaper (various gradations)
• rotary tool with sanding drum and felt wheel or very much patience
• polishing compound

The video will show the most, I will try to describe the rest below.

First, I removed the old scales, the operation is very simple, after pulling the tweezers and a toothpick, I put a small spatula in their place, the scales came off without much resistance.

I placed the covers side by side on the scanner and scanned in high resolution (720 dpi) to see all the details. You will probably ask why I used the scanner instead of the camera that everyone has today, even on a smartphone. Well, the reason is very simple, the scanner will give me a reproduction scale of 1: 1 no matter what resolution I use and additionally it is free of distortions introduced by the camera's optics. Thanks to this, I have a file to be processed based on which I will determine not only the shape but also the exact dimensions of the final product.

The rest of this step could be done in full, e.g. in Fusion 360, but I did not know any software of this type at the time and I was able to help with what I had.

I imported a file from the scanner into a vector graphics program, I use CorelDraw, but Adobe Illustrator or free Inkscape will work as well. I processed all the elements that affected the shape and functionality of the tool... and a few unnecessary... but they look cool ;)

Now the biggest disadvantages of the method that I have used are revealed. When I had all the necessary lines drawn, I had to draw the exact path of the milling bit based on them, including the offset and the depth of each passage. If you have CorelDraw, you can view the effect of my torment in the attached victorinox.cdr file. Drawings made separately for milling bit with two diameters were exported and converted to g-code.

Today I could do this work on makercam.com based on my basic drawing saved in the .svg file, which I highly recommend if you want to do something with my method. This method is actually nothing but cnc work in so-called 2.5D instead of full 3D.

If you want to take advantage of the effects of my work, you can use ready-made files for the CNC milling machine that I uploaded:

victorinox-01.ngc for 3,175 mm (1/8 in)

victorinox-02.ngc for 1.4 mm

The beginnings of the bits must be zeroed at the same Z axis height.

I set the zero of the Z axis gently below the surface of the wood, thanks to which the bit will sink gently and level the surfaces during processing. After finishing the first file, I had cut out the shape of the scales and an even surface. After changing the bit to a thinner one and loading the second file, I carefully set the zero of the Z axis (bit end) at the same height as before. It remained only to admire the slowly emerging shapes of inlets and pockets! A very satisfying process...

After finishing work on the CNC, I had to free the semi-finished products from a piece of mahogany, the easiest way would be to do it on a band saw or table saw, but I did not have any of them at that time, so I cut off the scales with a hand saw.

I brought the scales to the final thickness using a belt grinder. The next step was to make inlets for tweezer and toothpick holders with a needle file.

The next step was to round the top of the scales, I started working with files, but quite quickly switched to a rotary tool. Of course, this can be done with files and sandpaper, but with hard woods you need patience.

The pin pocket was not milled on CNC because the 1.4 mm bit was too thick for this operation, so I made it with a precision knife.

I decided to strengthen the pockets (which are supposed to keep the covers in place) with CA glue. I gently let a drop of glue into one and drained the excess with a paper towel, so that the wood was soaked with glue but the hole size did not change.

I finish the external sides with CA glue, I did it for the first time, so the coating did not come out too usmooth, this technique requires some practice and I recommend working on some waste. In general, the principle of making such coatings is simple. We apply a layer of glue, after drying lightly sand and apply the next one.

Thinner glue and thinner layers = nicer finish.

More layers = greater depth of finish.

When I reached the desired thickness of the coating, I sanded everything for smoothing and polished using a rotary tool once again, this time with a felt tip.

I covered the rest of the inside of the scales with linseed oil.

This is the moment when, unfortunately, my camera died.

I placed the covers on the sides of the SAK and put it in a vice secured with thick fabric, closed the vice and... THE END

All that is left is to put the tweezers, toothpick and pin in their place and enjoy the splendor!

Where you can find me:

YouTube: https://www.youtube.com/catlighting

Instagram: https://www.instagram.com/catlighting

Facebook: https://www.instagram.com/catlighting