Products - Thread Repair Index - Wire Thread Inserts

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With using Wire Thread Screw Inserts provide a positive means for protecting and strengthening tapped threads in any material:

When Threads become stripped, worn or damaged for any reason, the strength and reliability are greatly reduce. Potentially dangerous situations are eliminated when the damaged thread is repaired with wire thread screw insert. The wire thread screw insert provides stronger, more reliable threads than the original tapped hole and at the same time eliminates the possibility of thread wear, seizing and corrosion.

Wire thread screw inserts are larger in diameter before installation than the Tapped hole. During installation the inserting tool tightens the insert which reduces the diameter of the leading coil so it can enter the tapped hole. After installation, each high tensile stainless steel coil expands outward against the tapped hole to permanently anchor the insert.

The Wire Thread Screw Insert has the most effective and universally accepted method of thread repair. Wire Thread Screw Inserts quickly and permanently restore stripped, worn or damaged threads to their original size and condition.

Wire Thread Screw Inserts work in any part or material - aluminum, magnesium cast iron, bronze, etc. Increasing use of light weight ( and soft) materials means more damage to threads. Wire Thread Screw Inserts repair for virtually every application.

Wire Thread Screw Inserts are made of cold-rolled Type 304 stainless steel wire (AS7245), work hardened to tensile strength above 200,000 psi and hardness of Rc 43-50 18-8 diamond shaped wire.. The finished surface (8-16 microinches) is exceedingly smooth, virtually eliminating friction-induced thread erosion.

Wire Thread Screw Inserts are precision-formed continuous helical coils. With minimal wall thickness, they are the most compact and lightweight inserts available.

Cross section view shows just little extra hole diameter is needed to provide the out- standing thread strength that Wire Thread Screw Inserts offer

Wire Thread Screw Inserts provide :
Stronger Assemblies
High Quality & Reliability
Fastening Integrity Superior to the Original
Wire Thread Screw Inserts eliminate:
Thread Wear
Corrosion
Galling
Rust
Wire Thread Screw Locking Inserts :
Wire Thread Screw Locking Inserts exert a prevailing torque on male threaded fasteners to prevent loosening due to vibration or impact. They eliminate the need for other, less desirable and costly locking mechanisms. They are excellent in adjusting screw applications by preventing the male fastener from creeping.
How Wire Thread Screw Locking Inserts Works :
One or more of the coils in the insert have a series of straight segments. Upon entry of the bolt these straight segments are flexed outwardly, creating pressure on the bolt. This pressure is applied between the flanks of the bolt thread so that contact area is maximized and the unit pressure is minimized. It is often possible to realize cycle life far in excess of specification requirements.
Bolt Protection With Wire Thread Screw Inserts
The Advantages
Wear and Tear Stability
Wire Thread Screw Inserts are manufactured from austenitic chrome-nickel-steel(tensile strength of minimum 1400 N/mm2). The formed thread provides a high surface quality. This guarantees a heavy-duty, wear and tear resistant thread with an extremely low constant thread friction force. This allows for a constant pre-stressing being achieved with the identical tightening torque upon repeated re-screwing. This leads simultaneously to a better utilization of the yield point for high strength screws. The torsion stress is noticeably reduced hereby: In comparison with cut threads, the surface roughness depth is up to 90% lower with Wire Thread Screw inserts.

Stronger Assemblies
The flexible characteristics of the Wire Thread Screw Inserts provide an uniform loading and tension distribution and with that, a perfect thread pitch angle. As per diagram shown conventional threaded joints over 75% of the load is placed on the first three threads of the assembly. The left shows how the spring like design of the insert allows the shear loading to be transformed into a preferable " Hoop Stress" or radial loading over the entire length of Insert. This provides a much stronger thread than can be obtained by conventional drilling or tapping.
This improved strength allows designers to select a fastener based on the minimum strength of the bolt, also allowing them to select smaller diameters and shorter thread lengths confidently even in low strength materials such as Magnesium or Aluminum alloys.
The material properties of the Wire Thread Screw Inserts ensure that locking and tight gripping of screws under normal environmental conditions does not occur.
Wire Thread Screw Inserts made from nickel based materials (INCONEL and NIMONIC 90) are Available for thermal high stressed thread connections, with or without any coating. Elasticity and Springiness is preserved even under high temperatures.

Wire Thread Screw Inserts from high-strength hard coated aluminum has been specially developed for utilization with materials liable to high corrosion such as magnesium. Contact corrosion is hereby ruled out.

DIFFERENT TYPE OF INSERTS
Free Running Inserts
Produced from precision profiled austenitic stainless steel wire wound into a helical spiral, POWERCOIL free running inserts have a spring like appearance. When installed using any one of a variety of manual or automatic tools they provide strong permanent internal threads which resist heat and corrosion. Once fitted their position is maintained by the action of radial pressure between their coils and the flanks of the tapped hole. This pressure exists because their free diameter is larger, by a calculated amount, than their installed diameter.


Screw Locking Powercoil Inserts
Powercoil screw locking (or prevailing torque) inserts are of particular value in applications subject to the effects of cyclic vibration or impact. In addition to the benefits afforded by free running inserts, POWERCOIL screw locking inserts offer the additional security of prevailing locking torque. This is achieved by the action of one or more polygonal grip coils positioned within the inserts length, which excert radial pressure on the male thread. Each grip coil consists of a number of tangential locking chords which protrude inside the minor diameter of the normal free running coils. As the male thread passes through these grip coils the locking flats are displaced thus exerting radial pressure or prevailing locking torque on the male thread. On removal of the male thread, the locking coils relax to their original form permitting repeated assembly whilst retaining a measurable level of prevailing torque. Note: it is recommended that only close fit plated or lubricated bolts or screws are used with screw locking inserts.
Insert Materials & Finishings
Produced from precision profiled austenitic stainless steel wire wound into a helical spiral, POWERCOIL free running inserts have a spring like appearance. When installed using any one of a variety of manual or automatic tools they provide strong permanent internal threads which resist heat and corrosion. Once fitted their position is maintained by the action of radial pressure between their coils and the flanks of the tapped hole. This pressure exists because their free diameter is larger, by a calculated amount, than their installed diameter.

Additional materials and or finishes/coatings are available for a variety of conditions as listed:-

ALTERNATIVE MATERIALS
Phosphor Bronze:
Non ferrous copper/tin alloy in accordance with BS 2783 PB 102 EH (equivalent specification AMS 7247 DIN 17677). This material possesses a very low coefficient of friction combined with good elastic properties and excellent resistance to corrosion fatigue. It is suitable for operation in temperatures ranging from -200C to 300C.

Inconel X-750:
Heat resisting precipitation hardenable nickel base alloy (equivalent specifications AMS 7246, EN 3018, W.NR 2.4669). This material possesses good creep rupture strength and corrosion resistance at high temperatures. Its lack of cobalt makes it ideal for use in nuclear reactors. Inconel X-750 is suitable for operation in temperatures ranging from -200C to 550.

Nimonic 90:
Heat resisting precipitation hardenable nickel base alloy in accordance with BS HR 503 (equivalent specifications W.NR. 2.4632, UNS N07090). This material possesses greater creep rupture strength and corrosion resistance than Inconel X - 750, but however its high cobalt content makes it far more expensive. Nimonic 90 is suitable for operation in temperatures ranging from -100C to 650C.
Alternative finishes and coatings

Cadmium Plate:

Electronically deposited Cadmium in accordance with DTD 904C/Def Stan 03-19 (equivalent specifications QQ-P-416 type II, LN 9368). Cadmium plating provides an excellent barrier between dissimilar metals dramatically reducing the effects of galvanic corrosion, its high lubricity and excellent corrosion resistance prevents seizure and galling between threaded components. Cadmium is unaffected by alkalis and withstands marine conditions far better than zinc. However, because of its toxic nature, the use of Cadmium plate is limited to the electrical and aerospace industries. Cadmium plate is suitable for operation in temperatures ranging from -200C to 235C.

Zinc Plate:

Electrolitically deposited zinc in accordance with BS 3382. Electro- deposited zinc is the most widely applied electroplated finish in industry. It provides properties similar to cadmium at a much lower cost. Zinc is suitable for operation in temperatures ranging from -200C to 250C.

Silver Plate:

Electrolitically deposited silver in accordance with DTD 939 (equivalent specifications QQ- S.365, EN 2786). Silver plating is used to prevent seizure and galling between thread components in high temperature applications and is most commonly applied to aero-engine fasteners. Silver plate is suitable for operation in temperatures ranging from -200C to 650?C.

Dry Film Lubricant:

Solid film heat cured molybdenum disulphide dry film lubricant coating in accordance with MIL-L-8937 provides a low frictional coefficient coating with excellent load bearing capabilities. Dry film lubricant prevents seizing and galling between threaded components and is particularly effective in screw locking insert applications. Dry film lubricant is suitable for operation in temperatures ranging from -100C to 250C.