oil filter tightness

[embee]

Oil filter cans are "usually" designed with a metal-to-metal stopper feature which bottoms out when the seal or O-ring is compressed the correct amount. Compressing O-rings beyond this will very often cause failure and leakage.
You can generally get them to that point by hand, you'll feel when it bottoms out. There is absolutely no point tightening it any further.
Sometimes space constraints prevent you getting a good hand grip on the can, in which case a filter cap tool is the ideal solution, generally filter cans have a multi-facet end for this purpose. You will feel the bottoming out point if you are gentle with it.