Bolt thread anti-loosening is one of those problems that stays invisible until a machine shakes itself apart on a customer site. Fasteners under vibration lose preload gradually, and once a joint moves, fretting corrosion finishes the job. Anaerobic threadlocker chemistry solves bolt thread anti-loosening by filling the thread gap with a liquid that cures only where air is excluded and metal ions are present, forming a tough cross-linked polymer matrix that eliminates clearance friction and blocks moisture, cutting fluids and corrosive salts.
How bolt thread anti-loosening chemistry actually cures
Bolt thread anti-loosening with anaerobic adhesives depends on two conditions working together. The adhesive stays liquid in the bottle because oxygen keeps polymerisation inhibited; inside the metal thread gap, oxygen is absent and the metal surface supplies ions that trigger the cure. The result is a solid that fills every microscopic valley of the thread form. That full contact is what separates a threadlocker from tape or a spring washer, both of which rely on mechanical tension that vibration can relax.
Bolt thread anti-loosening selection then becomes a question of strength class, and JOME grades the choice by colour, matching disassembly force to service reality. Getting this wrong in either direction causes complaints: too weak and the joint backs off, too strong and field service destroys the housing. The four grades below cover the practical range, from delicate instrument screws to permanent chassis locks, and each one trades vibration resistance against the cost of future disassembly.
Bolt thread anti-loosening also replaces a stack of mechanical devices. Spring washers, lock washers and nylon-insert nuts all add parts, add weight and add assembly time, and none of them seals the thread against corrosion. A single drop of anaerobic compound does the locking and the sealing at once, which is why high-volume lines moved to threadlocker chemistry years ago.
Purple / low strength for precision and micro fasteners
Bolt thread anti-loosening work on small machine screws starts with the purple low-strength grade, formulated for fasteners below M6 in power tool housings, camera modules and delicate hardware. It provides vibration protection while permitting manual disassembly with hand tools, and it will not damage threads in light-alloy housings such as aluminium or zinc, which gall easily when a high-strength compound is forced apart. The grade cures at room temperature and serves from -40℃ to 120℃, and for instrument makers that combination of removable strength and alloy safety is the whole requirement.
Bolt thread anti-loosening at this scale is often applied on automated lines, where low viscosity helps wetting and fast fixture times keep takt stable. For electronics and instrument assemblies where screws may be adjusted during commissioning, the purple grade is the forgiving option and pairs well with the sealant range on fluid-facing screws. JOME supplies it with TDS documentation and free samples so line trials can confirm dispense volume before a production commitment, and the pre-coated threadlocker grades extend this to factory-applied patch systems.
Blue / medium strength for general assembly
Bolt thread anti-loosening on general machinery bolts from M6 to M20 is the job of the blue medium-strength grade, the standard choice for building hardware, furniture connectors and general machinery. It balances high vibration resistance with serviceability: disassembly requires standard hand tools or local heating in the 120℃ to 180℃ band, and the service range runs from -45℃ to 130℃.
Bolt thread anti-loosening on maintenance-heavy equipment should favour this grade almost by default. When a bearing house or gearbox cover comes off every overhaul, a red permanent compound turns routine service into a heating and extraction exercise. Design the joint for the technician who will open it in five years. JOME publishes service temperature ranges for every grade precisely so maintenance planners can make that call before drawings freeze.
Red / high strength for heavy vibration
Bolt thread anti-loosening in heavy equipment, automotive chassis, power generation and tool spindle bolts above M20 calls for the red high-strength grade. It delivers high shear strength that resists catastrophic vibration loosening under extreme loads, and the lock is permanent: disassembly requires exposure above 220℃ to break the polymer down. The service range is -55℃ to 150℃.
Bolt thread anti-loosening decisions for structural joints should account for the forces that a hand tool cannot deliver. Does the joint carry impact load? Is it a spindle that spins at speed? If the failure mode is catastrophic rather than annoying, the red grade earns its place and the disassembly cost becomes acceptable.
White / PTFE thread sealant for fluid and gas lines
Bolt thread anti-loosening and sealing overlap on threaded fluid connections, and the white grade handles that zone. Formulated with PTFE fillers, it delivers low-locking-force sealing on hydraulic valves, water lines and pneumatic fittings, replacing traditional PTFE tape and eliminating the shredding and thermal degradation tape suffers in service. The working range is -40℃ to 135℃.
Bolt thread anti-loosening on hydraulic fittings carries a second requirement the mechanical grades do not: the seal must hold pressure without cold flow. PTFE particles suspended in the anaerobic matrix fill the root of the thread while the cured resin locks it. The joint can still be adjusted during assembly, then cures fully in service; the low locking force of this grade is deliberate, unlike the red grade’s permanent lock. Applications on structural adhesive joints at the same machine often run this sealant alongside heavier bonding grades.
Process notes that decide whether the lock holds
Bolt thread anti-loosening performance is only as good as surface preparation. Degrease oily fasteners before assembly, because drawing oil and cutting fluid block the metal contact the cure needs. Apply the adhesive to the engaged thread length only. And allow full cure before applying service load; the JOME grades above cure at room temperature, but thick bond lines and low temperatures slow the reaction, so the cure time in the TDS assumes a stated ambient temperature; plan for slower set in unheated plants.
Bolt thread anti-loosening validation on a new joint should include a vibration test at the assembly level, not just a bench torque check. JOME manufactures anaerobic adhesives in its own factory and supplies customers in more than 30 countries, with RoHS and REACH compliant grades available for export assemblies. It’s worth asking your supplier for shear strength retention data after thermal ageing, because that number predicts field behaviour better than initial breakaway torque ever will.
Choosing the grade without overthinking it
Bolt thread anti-loosening selection collapses to one question: what should disassembly cost later? Purple and blue answer “a hand tool”, red answers “a heat gun and patience”, and white answers “it should never need to come apart, but if it does, the threads must survive”. JOME manufactures all four grades alongside its wider structural adhesive and sealant ranges, so a single supplier conversation resolves thread locking, sealing and structural bonding on the same machine.
Bolt thread anti-loosening is easier to specify when the fastener schedule and service plan are on the table from day one. Send those to the JOME technical team through our contact page and the grade selection is usually a one-day exercise. Engineers working on the adhesive side of machine assembly can continue with the die attach adhesive guide for electronics, and the anaerobic adhesive range lists every grade covered here alongside related JOME industrial bonding products. The Shanghai JOME Industrial homepage summarises the full industrial adhesive portfolio.