Feeling adventurous? This is a trick bolt you can give to someone. It threads in the middle to allow you to put the nut on, then thread it back together and the seam will disappear, as if it was printed right onto the bolt. My friend used to make them on his lathe, I thought it would be cool to print. The overall height is 58mm and the thread is 2mm on the outside with a 0.2mm clearance, and the thread on the inside is 1.5 with 0.2mm clearance. I have not printed this yet. Open to suggestions!