I am making a plinth (base) for a quick-change tool post. The plinth has a16.05mm vertical hole in the center. Through this hole, I will press a post (threaded at the top) for locking down the QCTP. There is a lip on the bottom of the post that fits into a recess in the bottom of the plinth to prevent the post from being pulled out of the hole (the post will be pressed through the hole from the bottom of the plinth). But I need an interference fit to prevent the post from rotating as I torque down the nut that clamps the QCTP. The length of engagement (the axial length of the hole) is 22mm.
Question: What should be the diameter of the post for a proper interference fit?
I thought it would be easier to fit if I heated the plinth and then pressed the post in. However, I still needed to know the proper diameter to make the post. So I tried heating the plinth in the oven to 400deg F and then measuring the diameter of the hole. But I could not get an accurate measurement (I suspect that the telescopic gage was expanding during measurement, due to the brief contact with the hot plinth, and then cooling and contracting by the time I got it in the micrometer). So I think I will have to rely on the cold diameter measurement of 16.05mm.
Thanks in advance for any assistance!