This adapter helps with screwing brass standoffs for computer cases and electronics. It should fit nicely, but it will be very tight. Slow down the print speeds to 40 mm/s. It's a small part - no need to rush. 

If it doesn't turn it over on the hex part and heat the bed to 60-65 degrees C (for PLA). While it's worm plug over the brass standoff and shake it a bit.

For better results set 80-100% filling and 0.15mm layer with 0.4mm nozzle.