Metric Screw Sizer (M2 - M8)

thingiverse

You can use this tool to quickly determine the size of your screws if you sort them by size. The available sizes range from M2 to M8 in increments of 0.5. These numbers are simple to mark with a permanent marker for easy identification. If your screws don't fit perfectly, even though you've confirmed they're the right size with a digital caliper, you may need to adjust your flow rate - possibly because you're over-extruding or perhaps under-extruding instead.