I used the standard extruder settings and sized the hole for the bolt head to match in Solidworks.

The size of the through hole is drawn in SW at .35"

The size of the bolt head, flat to flat, is drawn in SW at .495" and .27" deep.

If you use a textured PEI plate , the texture it leaves will match the fuzzy skin settings here. Settings for the larger knob has fuzzy skin turned on and uses the contour option. 

I have the knurled knob set to print with fuzzy skin off.