Nickel Calibration Test
thingiverse
To verify round holes, create a simple test modeled after an American nickel's dimensions (21.21mm diameter and 1.95mm thickness). The test has an internal diameter of 22.0mm and height of 1.95mm. This test checks "Bottom" settings and solid top layers. Place the nickel in the model to identify any printing issues, then adjust your printer accordingly. For more calibration tips, consult the RepRap wiki (http://www.reprap.org/wiki/Calibration). Typically, it involves changing steps per mm in the firmware. Find 3D printers on Gearbest (https://www.gearbest.com/3d-printers-3d-printer-kits-c_11399/?lkid=13099383), and follow John Ecker on Twitter (@mrjohnecker) or watch his YouTube channel (https://www.youtube.com/geodroidjohn).
With this file you will be able to print Nickel Calibration Test with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Nickel Calibration Test.