I am quite new to CNC machining and want to design two parts which should be accurately aligned with each other. I searched online and many people suggest the use of two dowel pins to align the parts, rather then using the screw holes directly. For the 1,5x5 mm, m6 tolerance pins (spaced 20 mm apart) which would fit my application, H7 tolerance holes are suggested for a "typical" transition fit. However, I failed to find any information on the required positional tolerance of the holes to ensure the parts can be assembled properly.
Can anybody provide me with a pointer or some explanation on how I would go about figuring out the position tolerance for the holes? Any help would be highly appreciated, thank you!
Thank you for all the suggestions so far. I added a simplified drawing to better clarify my design intent. I want to ensure that when the two parts are assembled (by lightly pressing two pins into the left part, sliding the right part over those pin -- preferably by hand --, and fixing the parts together using M2 screws) the distance between the 4mm H7 hole on the left part and the 12mm H7 hole on the right part is within 11mm +/- 0,05mm (considering the position tolerances of those holes as well as the position tolerances for the alignment pins).