Make a Bicycle License Plate With Laser Engraving

I periodically ride in various bicycle tours, such as Pedalers Jamboree, the Big BAM, and RAGBRAI. These are not races. They are more like parties on wheels. Some riders put license plates on their bikes to identify the group they are with, especially on RAGBRAI, where teams have humorous names. You can, of course, make plates with identifying information or whatever you desire. I put together this instructable to demonstrate how to make a bicycle license plate. Its' quick and easy.

Tools

Laser engraver

Ruler

Pen

Hole punch

Diagonal pliers

Materials

Anodized aluminum business cards: very inexpensive; available from aliexpress.com in various quantities and colors.

Zip ties

Paper towel

Water

Use whatever design and layout software you are familiar with. MS Publisher is good, but you could use Word or even PowerPoint. I confess to using PowerPoint, mostly because of the ease and familiarity developed from having used it at work for many years. The aluminum business card is 86 mm long and 54 mm high. This approximates a 1.6 aspect ratio (length/height). The default 10" x 7.5" slide in PowerPoint is already perfectly proportioned. The graphic will be shrunk to fit the plate before engraving, so the size during design is not important, only the proportions. You will probably want a border on your image, so first drop in a rectangle with rounded corners. Adjust the size until it has the minimum margin without touching the edges of the slide. Before you go further, put markers for mounting holes 1.4" from the sides and 0.75" from the top of the slide. On the plate, the holes will end up 12 mm (1/2") from the sides and 8mm (1/4") from the top. Make the markers by inserting a circle shape 0.5" (which will end up 4 mm after shrinkage) in diameter. Place it in position by right clicking on the circle and selecting Format autoshape. Click on the position tab to set the location. Copy and paste the circle. Move the new copy into position for the other hole. Drop in a graphic if you have one, and add text, avoiding the mounting holes. See images for examples. Save the graphic in a suitable format, such as JPG or PNG.

If you have a laser engraver, I assume you know how to use it and can make appropriate modifications to these instructions. I have the Atomstack A5 and I use the freeware app LaserGRBL to drive it, so that is what I will describe. For clarity, I will put the LaserGRBL commands in italics. Load the graphic into LaserGRBL (FILE/OPEN FILE). Click the Autosize button to crop out extra white space around the graphic, though there should be very little. Choose the conversion tool appropriate to your graphic. I used Vectorize! with Horizontal Filling and 3 lines/mm for the Team Beer Legs plate. This engraving will be akin to a black and white image, as you only have two colors to work with: the anodized color and the bare aluminum (exposed by the laser). If you have an image with a lot of shading, you might need to use dithering (instead of vectorization) to make a half-tone. Click Next. I've found that LaserGRBL distorts the original aspect ratio, so you might need to tweak the dimensions a bit. It took me three tries to get it just right. Unlock aspect ratio and adjust size to 80 mm width and 51 mm height. This will give you a small margin around the edges of your round-cornered rectangle. Click Create! Choose the Grbl menu and Material DB. Select your engraver or a similar one and Aluminum Alloy/Engrave.

Find the center of the plate: Place a ruler diagonally across the plate from corner to corner and make a small mark with a pen near the center. Do the same across the other corners and make a second mark that intersects the first to make an X. Place the plate under the laser engraver, X side up. Adjust the height of the laser to the correct focal length. Turn on the engraver and click the Center then Focus buttons. The laser should be shining faintly. Move the laser or the plate so that the laser is shining directly on the X mark. Make sure the plate is square relative to the engraver. Click the Frame button and watch the laser outline the rectangle that will encompass the graphic. Watch the distance between the laser beam and the edge, which will indicate whether the plate is square and centered. If it does not fall on the plate exactly as you desire, move the plate to where you think it should be and hit Frame again. Repeat until you have the position of the plate precisely where you want it. Now, the moment of truth: Click the Play button to start the engraving. The video shows the engraver carving one plate. The recording has been sped up 6x to make it play in about a minute because I find watching videos of engraving REALLY BORING.

Wipe off the soot with a moist paper towel. Don't like how it turned out? Redesign and make another. The plates are cheap and the process is fast. Use an office-type paper punch to make the mounting holes where marked. These business cards are thin enough that the punch goes right through, but they are still remarkably tough. Handle carefully while punching though, to avoid distorting the metal. You can purchase thicker ones, but they will cost more, of course, and you might have to drill the holes. Use small zip ties to attach the plate to the seat rails or rear rack, and trim them with diagonal pliers. Bike on!

Final note: I've heard it said that one should not put name plates on children's bicycles because creepers can then call the child by name and pretend they know them. Although the story may be apocryphal, you've now been made aware.