Single Row Pin Header Snapping Tool, 2 pin thru 20 pin, 2.54mm 3D Printer File, FREE Download

Download the STL file to print your own header snapping tool.

This is successfully printed using the Cura 5 slicer with Overture Space Gray PLA on an Ender 3 at 200 degrees nozzle temp and 60 degree bed temp.  10% infill, no support, right side up..

Cura 5 slicer settings:

Layer height 0.20mm, thinner layer heights may cause the header strip to be tighter in the slot

Cura 5.0 experimental setting "Slicing Tolerance" set to "Exclusive".  If this setting isn't available in other slicers then one will need to experiment with other settings in order for the pin header strip not to bind in the slot.