The detent ball is the only place I ever put grease in any of my 10 CRKS, or any knives for that matter. I lube the washers and pivot with W10 NanoOil and put a dab of Finish Line Extreme Fluoro on the detent which smooths everything out and makes my CRKs all flickable. I do like my 'Zaan (WC StarTac) though it is the fussiest of all my Reeve knives to open and close. CRK mentions that the thumb opening action should be forward, not out, which does indeed work best.
So...I just got my StarTac out while writing and it was kinda stiff as it's been sitting awhile, I figured to tune it up and take it apart, thinking I could unscrew the over-travel stop and bend the lock bar a little, as it is pretty damn stiff. I soon learned that the OTS is press fit, putting the kibosh on that idea.
The knife was clean inside so I just re-lubed the washers and pivot, got that dab of Finish Line on the ceramic ball interface, and left the pivot screw just a little loose, which doesn't result in any play or centering issues. The opening action is flicakbly great again, but even properly lubed the 'Zaan is definitely not the easiest knife to close. With my arthritic old carpenter's mitts I've adopted the habit of moving my pinky to the show side of frame- and liner locks for better leverage and to get my thumb to more of a right angle to the lock bar which helps a lot, especially with stubborn closers like the Umnumzaan. Even one closing leaves a depression in the end of my thumb--it's definitely not a fidget toy....