Hand Jewelry Holder With Copper Clad Circuit Board Inlay

Have you ever tried to embed pieces of metal into wood in order to give the piece a spectacular appearance? I tried it some time ago, but the results I obtained were disappointing. Cutting solid sheets of copper or aluminum on my little, underpowered CNC has, in certain cases, given me some problems. The edges of some pieces that I have cut have not been perfectly defined. I have filed them by hand trying to correct the visible defects and they have lost details, which means that afterwards they did not perfectly fit in the wood. I have also broken several bits by incorrectly setting the cutting parameters for these metal pieces. To prevent the bits from breaking up, I have used thicker ones, but I have found they work really difficult in narrow and small designs. In short, these were aspects that stopped me from applying this technique.

On the other hand, I am used to easily cutting circuit prototypes on my CNC machine. All of my circuit prototypes are first made on blank PCB boards and cutting these types of boards with my CNC machine, even in the most complicated ways, is not a problem. I always get the expected outcome! Bearing this in mind and not giving up the previous desire, the following idea came to me: Will it be possible to insert cut pieces of copper clad Circuit Boards into the wood and obtain a very similar effect to embedding solid copper? This Project is a proof that it is possible. Some of the advantages of using this material are the following: --- Appearance similar to using solid copper sheets --- Feasibility of using very thin bits --- Less machining time as the travel speeds can be increased --- Possibility of making narrow cuts and complicated designs --- The cost of production is decreased as the PCB boards are cheaper --- Possibility of using less powerful CNC machines.

---CNC Machine, I used this one (https://amzn.to/3l63ujM)

--- Drill Polishing Pad Kit (Optional) (https://amzn.to/3euVZl2)

---Rubbing Compound (Optional), I used this one (https://amzn.to/3rHZ5WB)

---CAD-CAM Software, FUSION 360 is a great choice

---Copper Clad PCB FR4 Double side: (1.5mm thick) Watch and Ring (W55mm*H50mm) , Base (W130mm*H130mm) Amazon: https://amzn.to/3bE17RZ

---Wood Sheets of your preference (10mm thick) Hand (H230mm*W130mm), Base (W130mm*H130mm)

---CNC bits: EndMill 1/16inch, EndMill 3/32inch and EndMill 1.15mm

---Abrasive Paper: Wood (120-400), Copper Clad PCB (1500-3000) Grit (Optional)

---Double Sided Tape: https://amzn.to/3cjGObI

--- Wood finish of your preference, I used this one: https://amzn.to/3ljbcao

Note: As an Amazon Associate I earn from qualifying purchases.

When I thought about developing this Project I considered the shape of a hand as the most natural way to hold rings and other relatively small jewelry. I thought it would be a good choice if I cut it from a board of some kind of wood with a dark brown hue. At first, I considered its base having a diamond-shape, but when the CNC machine cut it, I just didn't like it and had to redesign it. I finally opted for a pattern in the shape of flower petals that I created from ovals in a circular pattern.

One aspect I wanted to achieve in this Project was the metal inlays, previously described in the introduction. What motivated me to insert them this way, was that when there were no jewels hanging on the hand holder, this piece seemed naked, looking like a setting object from a horror movie ( hahaha just kidding)! Small embedded details such as a simulation of a ring and wristwatch, as well as discreet copper outlines at the base, I believe would make it really attractive.

I thought that maybe it would be useful for some of you to also offer the STL files, in case you decide to get this stand in a 3D printer and not in a CNC machine with natural wood. Perhaps, you can get other interesting results if you choose to use some combination of plastic filaments. They are also attached below.

Once you download the DXF / SVG files you will need to import them into your CAD-CAM software. Here are some suggestions:

G-Code for the machining of the wooden hand: I suggest you use a thin bit like the 1/16 inch to make the pocket of the parts of the watch. Since the ring pieces are quite small, they were programmed with a 1.15mm bit. In the image of the hand that I attached in this step, the areas of the watch and the ring that must be slotted are shown in purple. I recommend slotting down to a depth of 1.7mm leaving a 0.2mm margin that should be occupied by the double contact tape that will be used to glue the PCB pieces to the wood. I programmed the outer cut of the hand with the 3/32 inch bit. If possible, program some taps to hold the piece during the final cut. With this you guarantee that the piece does not come loose and you cannot damage its finish. I suggest making the slot in 1 or 2 passes and the external cut in 3 passes.

G-Code for the machining of the wooden base for the hand: Here you must make the pocket of the outer edges of this piece, as well as the pocket of the edge of the central hole. These areas are also shown in purple in the attached image above. The 1/16 endmill was used for these pockets. The depth as in the previous step is 1.7mm. Once the pockets have been made, you must also program the cut of the inner and outer pockets of this piece. For this, I used the endmill 3/32 inch. I suggest making the slot in 1 or 2 passes and the external cut in 3 passes.

Note: LEAVE AN ADDITIONAL 0.15MM CLEARANCE IN THE POCKETS OF ALL WOODEN PIECES. THIS WILL FACILITATE THE CORRECT INSERTION OF THE PCB PIECES INTO THE WOODEN PIECES.

G-Code for the machining of the PCB parts: In the attached image above the contours to be cut on the PCB boards are shown, they are also marked in purple. Something very important here is to use the same cutter with which the holes were made for the wooden pieces (hand and base). I remind you that it is the endmill 1/16 inch for all except the endmill 1.15 mm that should be used to make the ring parts. You could use another bit, but it guarantees that it is the same in both materials respectively. Cuts can be made in this material perfectly in one pass.

If you want to save the process of creating the G-Codes, I am attaching the ones I used so that you can import them directly into your CNC machine. Take into account all the tools that I used and be consistent with using them in your machining. Also check that the material you have to cut is of the dimensions declared in the list of materials.

The (0,0) of the X, Y coordinates of the trajectories were fixed in the center of the material.

This is an optional step and will depend on your preferences for how you want the copper to stand out in this holder. I preferred a glossy finish. The PCB boards that I used had already been stored beforehand and had corroded a bit. To give them a lustrous appearance again, I first decided to sand them with a 1500 sandpaper and later with a number 3000. After this sanding, even with the 3000, micro-scratches prevail, to remove them use the 3M Rubbing Compound and the polishing kit declared in the material's list. It is common that when you are doing this process a kind of dark residue is created, which if you are not careful will spread throughout your work place, so keep that in mind. After you are satisfied with the result, rinse the piece with water and some detergent and then dry it with a cloth.

You must first fix the table on your CNC machine. Keep in mind that the hand will be cut through the entire thickness of the board, so you can damage the CNC bed if you don't have scrap material placed underneath. Put the Spindle/Router in the position where you set the coordinate (0,0) run your machine and make the pocket cuts of the clock (1/16 inch bit) and the ring (1.15mm bit). Once finished, change the bit and put the 3/32 inch one and execute the external cut of the entire hand piece. Turn off the CNC machine and remove the part. If you used taps you must cut them. Lightly sand any imperfections from the piece.

You must first fix the PCB onto your CNC machine. Keep in mind that this piece will be also cut through the full thickness of the board, so you can damage the CNC bed if you don't have scrap material placed underneath. Put the Spindle/Router in the position where you set the coordinate (0,0) and place the bit for the pocket cuts of the outer and inner edges of this base (1/16 inch bit) and start cutting. Once finished, change the bit and put the 3/32 inch one and first execute the cut of the internal hole and then the external cut of this entire piece. Turn off the CNC machine and remove the parts. If you used taps you must cut them. Lightly sand any imperfections from the pieces.

You need to fix the PCB on your CNC machine first. It is important that you use double contact tape for this operation since the pieces you are cutting can come off and be ruined if they collide with the Router bit or Spindle while cutting neighboring pieces. They are very small pieces and it is a very light material so they can jump easily. Keep in mind that these parts will also be cut through the entire thickness of the PCB (1.5mm), so you can damage the CNC bed if you don't have scrap material placed underneath. Put the Spindle/Router in the position where you set the coordinate (0,0), place the bit for the cuts (1,15mm) in the Router or Spindle and start cutting. Once the cut is finished, turn off the CNC and remove the cut pieces. Lightly sand any imperfections from the pieces. It is a material that you must treat with great care during this sanding process, you should not go over with the sandpaper otherwise the pieces will not fit correctly in the pockets made in the wooden pieces.

You need to fix the PCB on your CNC machine first. It is important that you use double contact tape for this operation since the pieces you are cutting can come off and be ruined if they collide with the router bit or Spindle while cutting neighboring pieces. It is a very light material so they can jump easily. Keep in mind that these parts will also cut through the entire thickness of the PCB (1.5mm), so you can damage the CNC bed if you don't have scrap material placed underneath. Put the Spindle/Router in the position where you set the coordinate (0,0), place the bit for the cuts (1/16 inch) in the Router or Spindle and start cutting. Once the cut is finished, turn off the CNC and remove the cut pieces. Lightly sand any imperfections on the pieces. It is a material that you must treat very carefully during this sanding process. You should not go over with the sandpaper otherwise the pieces will not fit correctly in the pockets made in the wooden pieces.

Glue pieces of double-sided tape to the back of the PCB cut pieces. With a cutter cut the surplus. You must be careful in this operation and try not to protrude pieces of double contact tape since they make it difficult to embed. Carefully glue each piece of PCB into position on the wood.

To provide protection to these pieces and highlight the beauty of the wood, it is advisable to apply some type of protection. In my case I put a little on these and spread them with a cloth. This protection will also offer protection to the copper clad of the PCB parts, avoiding their corrosion and loss of gloss. Remove the excess with another cloth if necessary.

It only remains to insert the hand into its base and with that you will have finished this jewelry stand. You can use some glue if you prefer, but I think that if you don't apply it, you can take it off and carry it with you easily, which in certain cases can be helpful.

From what I have been able to experience when embedding this material into wood, I can tell you that the results that can be obtained are amazing. The ease of machining of PCB boards is very advantageous and offers a spectacular appearance when combined with wood.

Last but not least, I gave this project as a gift to my wife. She immediately filled it with her jewelry and outlined that it is also a beautiful furniture piece that is worth to be in a visible house spot.

I hope that this Project awakens in you new ideas for its application. Do not forget to share them! Good luck!