Penny Weight Fidget Spinners

thingiverse

These are fidget spinners that utilize pennies as weights in the spinner's arms. The print pauses to insert the pennies, then they're sealed in by subsequent layers. There are six variants of this model included. Three of these variants feature a 608 bearing inserted into the center. The other three models have a bearing outer ring at their center and are designed for insertion of 4.5 mm steel BBs and a printed inner bearing ring along with a printed bearing BB spacer. The penny cavities come in different sizes, each suitable for a specific type of Canadian penny. The first size is 4.68 mm, allowing for three pennies minted in the year 2000 or later to fit inside. To accommodate this, the print needs to be paused at a height greater than 5.84 mm. The second size is 4.92 mm, designed for pennies minted in 1979 or earlier. In this case, the print should be paused at a height of more than 5.96 mm. Lastly, there's a 6.00 mm penny cavity that can fit four Canadian pennies minted in the year 2000 or later. The pause height for this model is greater than 6.5 mm. These three variants without built-in bearing outer rings spin well but rattle and shake slightly due to their design. They don't offer the same smooth spinning experience as steel bearings, which can be inserted into these models. To maximize strength in the inner bearing ring and spacer, I print them at 100% infill. If you're printing any of these models, be prepared for post-print cleanup. All my prints had a small bump on the bottom layer of the bearing parts, which I removed with a file. You may need to scale down the finger pads by 3-4% so they fit snugly into the printed bearings. For better results, I print mine with four perimeter shells, making the twisted pin parts solid. Before inserting the finger pads into the bearing, I apply a small amount of SuperLube Synthetic Grease to each BB. American pennies have the same diameter as Canadian ones, so they can be used in place of them if needed. The most weight-efficient fidget spinner will use 1979 or earlier pennies since they weigh 3.24 grams each, compared to the newer pennies' 2.35 grams. The next best option would be a model that has four pennies in each arm. Since the older pennies are thicker (1.53 mm) than the newer ones (1.43 mm), only new pennies can fit. Depending on your printer's quality and filament type, the layer printed over the pennies might appear messy. The 4-penny model leaves little room for subsequent layers to cover up any flaws, resulting in a slightly rippled surface. If you want a completely smooth top, consider printing one of the 3-penny models. The prints won't tolerate warping or else the pennies may not fit properly. To ensure proper cooling during this critical layer, I turn off my fan for the first layer and then switch it on for the rest of the print. Since my printer doesn't support pausing via G-code, I manually pause the print and insert the pennies when the perimeters have been printed and the infill starts. To simplify this process, I include a tab file that correctly positions these pauses for all three variants of the model. If you're using this tab file, immediately pause the print and insert the pennies once the tab layer's infill begins. This design is a remix of Tri Fidget Spinner Toy by 2ROBOTGUY, scaled up to 101% in X and Y dimensions for better bearing fit. The bearing parts themselves are a remix of 608 bearing (4.5mm steel BBs) by SiberK. For optimal results, I recommend printing these models with first-layer heights set at 0.2 mm and other layers at 0.12 mm. While the importance of layer heights is unclear, this was my chosen setting for all prints. Tip: When printing these fidget spinners, use 3M General Purpose Masking Tape High Adhesion for maximum adhesion and to prevent warping. I previously used 3M Scotch-Blue Painters Tape but found it didn't stick well to the build plate, causing spinner arms to lift slightly. The general-purpose tape works better as it sticks both to the build plate and the prints very well.