That's a really good tip for getting them flush, going to remember this! Funny enough I'm printing something now that needs M3 inserts, but I recessed them behind another slightly larger radius 🙃 going to see if I can use a metal dowel or a flat-end hex-key to similar effect then!
imbedded nuts have a huge disadvantage because they rely on print tolerance to be perfect or they will spin in place. headsets are much better and just a strong gripping the melted filament on all sides. The heatsets in this video are not structural and only holding on a panel.
Yeah, the fact people build $150 MACHINES TO PUT IN HEAT SETS IS SO CRAZY....Like did you even try first. The if the heart is on a non-square or parallel surface the machine is no use anyway.