I've done a couple of measurements with the Mitutoyo bore gauge, and it seems that the surface is actually conical (at least on my part), and not super precise. The cone could be a result of deformations after the seal replacements in the past (it was replaced at least 2 times).Yeah, that's a datum I'm looking for as well. 0.2mm interference (~0.008") seems like an awful lot. In our design exercise, I used .0025" (~.06mm) as the interference fit. But this particular metals engineering is something I don't do; I've merely watched engineers I've worked with spec this stuff.
The inner diameter on the bottom of the groove is anywhere between 54.86 and 54.9 mm. And at the top of the groove 54.97-55.0 mm.
It is quite simple and mainly depends on the material and the temperature difference. I usually calculate the thermal expansion of the material.I also don't have any expertise in interference fit. But there are many online metal interference fit tables, I'm just not experienced enough to know how to interpret them or know any assumptions / caveats
For 55mm OD aluminum cap the temperature difference of 100 degrees gives you the expansion of approx. 0.1-0.12 mm.
So if you want to squeeze the 55.12mm cap to the 55.0mm hole one will need to heat up the hole (or cool down the cap/shaft) by 100 degrees.