The latch bolt of the mortise lockset in a metal security door is stiff. I worry about the long-term effect of slamming the door in order to drive the stiff latch bolt back and allow the door to close in its frame.
There is much discussion of lubricating the pins and the cylinder of the keyway, centering around the pros and cons of graphite and non-greasy lubricants. But there is no discussion of how to lubricate the portions of locksets which are not along the keyway.
I plan to remove the mortise lockset and, hopefully, open the case to expose the latch bolt mechanism. Can I assume that the latch bolt mechanism is simply a moving metal part in a metal housing and lubricating it is unrelated to the controversy over whether graphite or graphite-substitutes are appropriate to keyways?
What to you think of this plan? Disassemble and clean the latch bolt parts. Remove dust and dirt along the moving path of the latch bolt. Lubricate the latch bolt mechanism either with oil, or possibly grease it?