Penny Tolerance Test -- No Calipers

Penny Tolerance Test -- No Calipers

Determine your printer tolerance with a United States penny. If the penny fits, then you've achieved the tested tolerance. If the penny doesn't fit, then your printer is printing too large or small.

This is useful if you don't have digital calipers, but still want a rough idea of how accurately you can print. 

This file should print very fast, with little wasted plastic, so it's easier to iterate your adjustments quickly.

Instructions

Print out these tests in your desired material. Use your most accurate slicer settings. Print and try the largest size first (+0.10mm). If the penny fits, then try printing the next smaller size down (+0.05mm), etc. 

The penny should fit exactly in the circle, and vertically in the slot. The penny should be exactly as thick as the print, too. 

Use multiple, new and undamaged pennies. Old pennies won't work because they have slightly different dimensions than new ones.

If your penny doesn't fit, then you need to:

•  calibrate your printer (mechanical, e-steps, z-offset, pressure advance, etc.);
•  and adjust your slicer settings (flow, temp, expansion/contraction settings, speed, etc.).  

Dimension Info

Penny size is based on the US Mint's info, not my own measurements.

• Diameter: 19.05 mm
• Thickness: 1.52 mm

Each model has a +0.XX in the filename and text – this means that the listed dimensions have been enlarged by that amount. For example, the ‘+0.02mm’ model has a hole of 19.07mm, and thickness of 1.54mm. 

The text size is very small, since if you're going for these accurate dimensions, then you should be able to print the text, too. The text thickness is about 0.6mm in most places.

Notes

The Fusion360 and .step files are available, so others can make this model for other coins/sizes.

Be aware of slicer settings that could impact the print dimensions, such as layer thickness, wall partial merging, etc. 

The thickness of the models overall 1.52mm. Only the circle and slot change dimensions.