Category Archives: CNC Machine

What do the CNC, Laser and a Light Switch Plate Have in Common?

You can make a light switch plate with a CNC machine, and then engrave a decoration on the plate with a laser.  I was inspired by Kenbo Studio’s YouTube channel A Cut Above,  when he used a scroll saw to cut out a switch plate in the shape of  Star Wars droid R2D2.  My grandchildren love Star Wars, so I searched the internet for Star Wars images and landed on a cartoon image of R2D2, a good test image for my project.

Before I post the details of the project, let me digress into the history of the light switch, which is so cleverly hidden by this switch plate. Wikipedia gives a brief history:

“The first light switch employing “quick-break technology” was invented by John Henry Holmes in 1884 in the Shieldfield district of Newcastle upon Tyne.  The “quick-break” switch overcame the problem of a switch’s contacts developing electric arcing whenever the circuit was opened or closed. Arcing would cause pitting on one contact and the build-up of residue on the other, and the switch’s useful life would be diminished. Holmes’ invention ensured that the contacts would separate or come together very quickly, however much or little pressure was exerted by the user on the switch actuator. The action of this “quick break” mechanism meant that there was insufficient time for an arc to form, and the switch would thus have a long working life. This “quick break” technology is still in use in almost every ordinary light switch in the world today, numbering in the billions, as well as in many other forms of electric switch.

The toggle light switch was invented in 1917 by William J. Newton.

“As a component of a building wiring system, the installation of light switches will be regulated by some authority concerned with safety and standards. In different countries the standard dimensions of the wall mounting hardware (boxes, plates etc.) may differ. Since the face-plates used must cover this hardware, these standards determine the minimum sizes of all wall mounted equipment. Hence, the shape and size of the boxes and face-plates, as well as what is integrated, varies from country to country.

The dimensions, mechanical designs, and even the general appearance of light switches changes but slowly with time. They frequently remain in service for many decades, often being changed only when a portion of a house is rewired. It is not extremely unusual to see century-old light switches still in functional use. Manufacturers introduce various new forms and styles, but for the most part decoration and fashion concerns are limited to the face-plates or wall-plates. Even the “modern” dimmer switch with knob is at least four decades old, and in even the newest construction the familiar toggle and rocker switch appearances predominate.”

This brought to mind a two-button light switch that I saw at my grandmother’s house when I was a child.  At the time, I didn’t realize the historical significance of this type of switch!  Today,  a light switch takes on many shapes and types. We can control our lights remotely with our smart phones. I have a lamp in my house that has a built-in speaker to play audio files, that can be controlled with my smart phone.  We have light switches with built-in occupancy sensors to control the lights. I have even worked with light switches that provided a binary input to a microprocessor to control the air conditioning system at a laboratory.   But enough digressing… back to the project.

Using Vectric software and the dimensions of a single switch cover plate,  tap files were generated for the plate outline and the switch plate hole. The Shark CNC machine was fired up and a wall plate cut from1/4 inch thick Baltic plywood. After separating the wall plate from the tabs holding it in place, I set the plate under a store- bought switch plate, which was used as a template to drill the screw holes.  I could have used the CNC machine to do this, but it would have meant a bit change.  If I was making a number of these at one time, it may have been worth the extra step to change the bit. The wall plate was then given a quick sand, and then painted with a high gloss white primer, followed up with a clear coat of lacquer. 

Next, I moved the plate over to the Full Spectrum 40-watt laser to engrave a cartoon image of R2D2.  I’m still working out the details on how to line up the laser image on a project, so it took a couple of test runs to finally get the image centered on the wall plate. With the white paint and clear coat on the plate, it only took one pass with the laser to get a satisfactory image. I did reduce the speed to 80% and left the power setting at 100%.

I’m going to continue to experiment with this project using different types of wood.  I may also try to not only engrave the piece with the laser, but also to cut out the shape using the laser. I also want to try to improve on the use of the CNC, to provide a profile on the border of the switch plate. I think for the time being the grandkids will be happy with an image of their favorite cartoon figure. I might make some switch plates with a feel-good motif for the parents, too… maybe a plate engraved with the words  “When In Doubt, Turn It Out!”

light switch plate craftsbyjennyskip.com
light switch plate

Christmas Projects: Wooden Tic-tac-toe Game

Looking for CNC projects to do for Christmas, I came across the Vectric Labs Blog where several ideas for Christmas projects were posted. One of the projects that caught my attention was a Tic-tac-toe game by Beki Jeremy in a 2014 blog post. This looked like something I could handle. I could use some ½ inch Baltic birch plywood and a couple of bit changes on the CNC machine and produce one, maybe even two or three.
Tic-tac-toe has always been a fun and often spontaneous game for children and adults alike. Children want to challenge adults to a game; that is, adults who can figure out how to lose, to make the children look good!

According to Wikipedia, a form of Tic-tac-toe may have been played during the time of the Roman Empire, first century BC. The game played at this time went by the name of Terni Lapilli. It is reported that the grid for this game were found chalked all over Rome.
In Claudia Zaslavsky’s book Tic Tac Toe: And Other Three-In-A Row Games from Ancient Egypt to the Modern Computer it is indicated that Tic-tac-toe may have had its origins in ancient Egypt. More recently, the game has taken on several different names including Noughts and Crosses, of British fame (1864) and Tick-tack-toe (1884). The American name of Tic-tac-toe didn’t come about until the 20th century. Wikipedia also reports that “In 1952, OXO (or Noughts and Crosses) for the EDSAC computer became one of the first known video games. The computer player could play perfect games of Tic-tac-toe against a human opponent.” By 1975, MIT students used Tic-tac-toe to demonstrate how a computer made almost entirely out of Tinkertoys could play the game.

Often the best outcome for two good players is a draw. If you really want your head to spin on your shoulders, delve into the combinatorial of Tic-tac-toe, the possible board layouts and game combinations. Look at the strategy of winning or obtaining a draw by choosing the first available move from a list in Newell and Simon’s 1972 Tic-tac-toe program. See more Newell and Simon here. But if advanced calculus is not your thing, get Newell and Simon’s list and challenge some unsuspecting five year old to a game of Tic-tac-toe. Or if you want to engage in an experiment to use Tic-tac-toe as a pedagogical tool to teach this five year old good sportsmanship, you could just cheat and beat the five year old.

For this project, I mounted a 2 foot by 2 foot piece of ½ inch Baltic birch plywood on the CNC machine’s sacrificial board. I pulled up the Tic-tac-toe file and checked the various tool paths to make sure it would work with my plywood. I did have to change the cutting depths to 0.51 inches to insure that I could cut all the way through the plywood. As it turned out, it would have been better to set this at 0.53 inches for my set up since the 0.51 inch setting was a hair short of cutting completely through my plywood sample. Other than this change, I used the original settings.

I loaded up the g-code for the profile cuts first and used a 1/4 inch shank 90 degree engraving router bit to make these cuts. Following all the profile cuts, I changed the bit to a ¼ inch shank 0.25 inch spiral up cut end mill to make the pocket cuts. Following the pocket cuts, I loaded up the various g-codes for cutting out the game board and X’s and O’s. These cuts provided tabs to keep the parts together until the parts could be separated with a sharp chisel.

All that remained then was to sand, seal and paint. Oh, and then to challenge my wife to a Tic-tac-toe game. Of course I would go first. 

 

a Wooden Root Beer Tote

As we experiment with 21st century technology, we find that unless we put a lot of our 50-year plus brain cells to work, this new technology will often move us backward, in lieu of forward, with our craft. In keeping with our blog’s theme, we decided to take a 19th century brew and apply a 21st century twist to it.

We love root beer. One of our children really loves root beer (at one time he actually placed 99 bottles of root beer on a ledge in our kitchen). Another son spent 2 years in the UK, where there’s not much root beer for sale. We bought some 2-liter plastic bottles of Mug Root Beer from Wal-Mart and spent about 10 times the price of the soda to ship it over to him. While my wife set out to explore the history of our favorite root beer, IBC root beer, I set out to construct a beer-of-the-root tote.

Many of my favorite You Tube woodworkers have designed and produced beer totes on their channels. Not being a beer drinker, in the purist sense, I’m not sure why you really need a beer tote. From what I have seen, beer bottles usually come from the store in a nice cardboard tote. In fact, even our IBC root beer comes in a nice cardboard tote. But I digress… on to the application of 21st technology to construct a wooden root beer tote.

As luck would have it, I found a CNC model of a beer tote on the Vectic web site. The model was complete and provided the g-code to run our Shark 3.0HD CNC machine. The model called for a 24-inch x 24-inch board, in my case a piece of 0.45 inch thick Baltic plywood. I anchored the board to a sacrificial board on the CNC machine, loaded the g-code and pressed go.

Shark CNC making beer tote jenny skip
ready to be cut out

As a side note, I did check out the tool paths to make sure I had the correct router bit installed, a ¼-inch end mill, and that I had the right cutting depth set for the plywood used. When the CNC machine had done its job, I separated the pieces and performed a dry fit.

beer tote parts cut out by CNC
parts and pieces cut out

This is where my lack of close attention to details caught up with me. First, I had somehow neglected to include the cutouts for the wedges that were designed to hold the tote together. This problem could be overcome with some strategically placed glue. So after a dry fit , I added a little glue, sanded the tote and applied a coat of white primer in preparation for my wife’s 19th century enhancements.

parts of beer tote
parts prepped for assembly

However (the eraser word) another synapse short-circuit became apparent when I tested the fit of the IBC root beer bottles. They didn’t fit!!! Evidently they are larger in diameter than an average beer bottle. After some serious hammer applications and some significant trial and error with the oscillating spindle sander, the bottles fit. The tote was reassembled and a coat of red, white and blue paint was applied. My wife added the finishing touches.

CVC root beer tote jenny skip
the tote

Root beer was popular in 19th Century North America. A tourist back then could find root beer throughout the country, but it wouldn’t necessarily be the same drink from town to town. The root used to make the concoction might be sarsaparilla, burdock, dandelion, or sassafras (real sassafras roots and bark were banned by the FDA in 1960 so now artificial sassafras flavoring is used). A foaming agent could be added, along with spices such as hops, anise, ginger, or many other choices or combinations (see Wikipedia’s article for the whole story).

We remember having homemade root beer at Halloween parties in the days of our youth, made memorable with the addition of dry ice, so it looked like a smoky, spooky potion! If you’re feeling adventurous, you might want to try Dr. Fankhouser’s Homemade Root Beer tutorial. It’s powerful stuff, so take care!

Root beer? Check. Root beer tote? Check. Now we have to figure out where to tote the root beer.