I quickly calculate proper tap-drill diameters using this simple formula. Tap-drill diameter equals nominal diameter minus thread pitch. For example, drill size for a 3/8-16 thread is 0.375 0.0625 ...

Correct tap drill sizes can be selected by following charts or by this formula: Tap drill size. Major (outside or O.D.) diameter of the thread minus 6 (.75 x 1.299) ...

i need one of those charts where you slide the card back and forth until the screw size you want is in a certain window, and then the rest of the windows have pertinent info in them, like ...

Luckily, your 3D printer takes care of almost all these steps. By simply designing your holes to be the tap drill size you can hand tap fairly strong threads in your 3D printed parts.

Luckily, your 3D printer takes care of almost all these steps. By simply designing your holes to be the tap drill size you can hand tap fairly strong threads in your 3D printed parts.