【转帖】mating cylinders

yang686526

mating cylinders
hello, i have a question regarding two parts that thread together.  each part contains a cylinder in which a shaft must be able to slide in and out of through both parts.  am i correct in that you cannot use the male/female threads as datums?  if so, what is the best way to control the position of the cylinders in relation to the threads for each part?
you can control the pitch circle, minor dia or major dia to a datum (the cylinder).
ewh is correct. you can spell out "major dia" or "minor dia" below the feature control frame (fcf). some shops/inspectors prefer it.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05
i appreciate the responses, one more question.  i'm essentially trying to get a virtual condition for the two cylinders.  am i able to use the threads as the datums instead of the cylinders to better control this?  the reason for this is that the threads will dictate the orientation of the two cylinders.  keep in mind that the cylinders are considerably longer than the threaded features of each part.  i hope i'm not making this too complicated.
yes. thds can be datums.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05