This page details our recommended tolerances for metric nuts and bolts when designing for different types of manufacturing, in particular FDM 3D printing and laser cutting.

The nominal values on the page are taken from the standards for metric sized screws and nuts. If you are unsure that your screws and nuts match the standard sizes, or you already know they're non-standard or imperial sizes, then please measure them and adjust your designed tolerances before committing to manufacture.

FDM

All these values were obtained by experimentation on our Stratasys F170 3D printers using ASA print material. These values may differ for different printers and different materials, but are a good starting point.

As the X and Y axes have much more granularity than the fixed layer height of the Z axis, the tolerances required differ depending on the orientation of the hole. These values are a compromise that should work for both, but may result in slightly looser or tighter tolerances depending on orientation.

Laser Cutting

Due to the kerf of the laser, cuts will end up as 0.1mm bigger then how they are specified. This means that often times you can specify the hole as the nominal size, and the kerf of the laser will make it large enough to be tolerant. These values have been determined using 3mm acrylic, values may differ for different materials.