This is a freecad file that includes 3 sketches for adding self tapping screw holes to your documents. Each sketch is constrained geometry of the pattern with the exception that it is not locked down on the plane and can be moved around. There are two versions of the sketches, one makes holes that are 0.2 mm larger than the screw threads, the V2 file has holes that are the same as the screw threads. Most will be fine with the V2 file, but if the holes are too tight, use the other file. There is a tutorial video linked here. https://youtu.be/Ze5fDIan1L0 The way to use these file is as follows. When you are ready to add screw holes to your project, open this file separately. Then, with your project in the active window, click on one of these sketches in the file tree and use the Edit/duplicate menu to copy it into your project. Unselect the x/y plane in the duplicate window, leaving just the sketch selected. Once you have the copy of the sketch in your project, Click on it and in it's data window, click the three dots in the map mode line. In the selection window that opens, select the first reference and click on the surface of your model where you want to add the screw holes to attach the sketch there. Then you can edit the sketch to constrain it's position on the surface. Once it's in place, you simply pocket it the depth you want your screw hole to be. Optionally, you can then add a second circular sketch on top of it and do a 1mm pocket with a -30 degree taper to make a guide for the screw at the top of the hole.