Summary Here is a set of simple v-blocks in 3 different sizes very handy for drilling holes in round objects. The hole in the middle is for clearance when the drill breaks through. The screen capture pictures shows a sample of use If you place the block on its end you can drill down the axis of your job also. You still need to centre pop the position of the hole as the drill will wonder on the curved surface. Print Settings Rafts: Doesn't MatterSupports: Doesn't MatterResolution: 0.1mm to 0.2mm Notes: These are best printed in the orientation they are found in the stl files as the surface in the v is flatter and not made of steps because of the angle when printed with these surfaces at 45 degrees. they still need to be cleaned up after printing