Will it fit? Let's check. With these tools you can see what your printer will make before you add holes to your design. Do you need a loose fit? Snug? Hammer fit? Do you want to make a hole that a bolt will thread into? These test sticks go up by .2 mm per hole. For example the first stick has the holes 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8 and 8mm holes. So you can find any type of fit for any round object from 6 mm to 18 mm with these. Don't bother printing them till you got your printer dialed in though. Write the sizes on them with a marker. This is a tool not a test print.