How old is your blue Loctite? As it ages, blue (like 242) does lose some strength. As a rule you should use purple (like 222) an fasteners smaller than 1/4" 20 but I DO use it on the small stuff when purple is not available... sparingly. Technically though I don't recommend it - get a bottle of each, they last for years.
Purple, blue and red all cure into thermoset plastic, filling air space between threads (so they can never rust inside) and using different degrees of "grab" to require different torque to get the fastener apart.
BEWARE: both purple and blue crumble when you break the fastener loose. RED however SHATTERS into tiny glass-hard triangles & shards, and re-embed, digging into the metal walls and getting harder to remove with each turn, until you snap the fastener off. Don't use red liquid Loctite on anything that needs to be removed some day. Green Loctite retaining compound is also brittle and permanent. On fasteners treat it as if it were red.
Also: the presence of metal ions and the absence of oxygen are what kick off the cure process. Threadlocker (TM) excess sitting outside the joint will never cure, the air keeps it liquid. If you lose the bottle cap, the Threadlocker inside stays liquid forever. (Not true for super glues, RTV's, etc.). But... If you touch the tip of your Threadlocker bottle onto a metal surface, then put the cap on, the presence of metal+absence of air will cure the tip. Then, when you use a pointy metal object to ream out the tip, it will cure right up again when you cap it. To open a new or clogged tip cut accross with a blade and you'll be fine.
So remember: Use Loctite Or Kiss Your Nuts Goodbye! (Copyright Mr. B. Studwell)