Threadlocker
Is threadlocker a replacement for proper torque?
No. It supplements correct preload; the fastener still must be tightened to spec so clamp force, friction, and adhesive retention work together.
Does threadlocker cure on all metals the same way?
No. Cure is anaerobic and influenced by metal contact and oxygen deprivation; practical cure speed and reliability depend on gap size, surface condition, and assembly environment.
When should a machine shop avoid using threadlocker?
Avoid it where the joint requires frequent disassembly without heat, where the material or temperature environment is incompatible with the product, or where thread contamination or poor fit would prevent reliable cure; in those cases a mechanical locking method or a different retention strategy is often more appropriate.
Threadlocker is an anaerobic adhesive applied to threaded fasteners to prevent loosening, seal joints, and reduce vibration-induced back-off. It cures in the absence of air and in contact with metal, forming a tough thermoset plastic between threads. Used on bolts, screws, studs, and set screws, it fills thread clearance and locks assemblies against shock and cyclic service.
On the shop floor, threadlocker is a routine part of CNC setup and millwork assembly. It is applied to engagement areas of bolts, studs, set screws, fixture hardware, machine guards, toolholding accessories, brackets, jigs, and adjustment screws, where cyclic vibration, shock, or repeated service access can loosen fasteners. The standard sequence is clean the threads, let the solvent fully evaporate, apply a small amount to the engagement zone, assemble to final torque, and allow full cure—commonly about 24 hours. Strength selection matters: low-strength products suit small screws needing hand removal, medium-strength products work for general nuts and bolts, and permanent-strength grades handle heavy-duty fasteners and harsh service. In blind holes, the root must be filled so the adhesive wicks through the full thread path. When applied correctly, threadlocker supplements preload, seals against leakage and corrosion, and keeps critical joints locked throughout production runs.
Contaminated threads: Oil, coolant, cutting fluid, or solvent residue on CNC parts can prevent proper cure or reduce bond strength, leaving fasteners that feel tight at assembly but loosen later under vibration.
Wrong product strength: Using a permanent-grade threadlocker where serviceable access is needed can force destructive removal, while a low-strength product on a vibrating fixture can allow screw back-out and positional drift.
Blind-hole under-application: A drop on the screw tip alone leaves most engaged threads dry in a tapped blind hole; unless the hole root is filled, the adhesive cannot wick through full engagement, so holding power drops.