Our Brands
Heli-Coil.
An American engineered fastening brand, now part of Stanley Engineered Fastening, that invented the wire thread insert. This helical coil repairs damaged threads, reinforces threads in soft materials and allows metric-to-inch or inch-to-metric thread conversions in existing tapped holes.
About Heli-Coil
Heli-Coil was developed in the early 1930s and commercialised through an American company that pioneered the wire thread insert as an industrial fastening solution. The Heli-Coil insert is a precision-coiled spring-steel wire formed to a diamond cross-section and installed into a specially tapped hole, where it provides the thread form into which a standard fastener is driven. The result is a thread that is stronger than the parent material, resistant to vibration loosening and repairable if it is ever damaged.
The application that first drove Heli-Coil’s growth was aluminium castings in automotive and aerospace. Aluminium is much softer than steel, and steel bolts driven into aluminium threads can strip the parent material under the torque needed to achieve a proper preload. A Heli-Coil insert installed in the aluminium provides a stainless steel thread form that can be torqued to the fastener’s specification without stripping. The same principle applies to magnesium, titanium and other materials used in lightweight structures.
In maintenance and repair, Heli-Coil thread repair kits are the standard solution for damaged threads in aluminium engine components, gearbox housings, cylinder heads and any threaded hole where the parent thread has been stripped. The kit provides the oversize tap needed to prepare the hole, the Heli-Coil inserts and the installation tool, which together restore a stripped thread to full specification without replacing the component.
Products We Can Supply from Heli-Coil
Heli-Coil thread repair kits. Complete kits contain the STI (Screw Thread Insert) tap, a selection of Heli-Coil inserts and the installation tool for a specific thread size. They are available for metric coarse (M4 through M24), metric fine, UNC and UNF thread forms in standard and spark plug configurations. The most commonly ordered kits in automotive maintenance are M8, M10 and M12 metric coarse for cylinder head, manifold and gearbox bolt threads.
Heli-Coil inserts, standard and tangless. Individual Heli-Coil inserts come in free-running and screw-locking configurations for installation in pre-prepared holes, along with tangless inserts for jobs where the installation tang cannot be removed afterwards (aerospace and precision work). Free-running inserts provide a standard thread form, while screw-locking inserts add a prevailing torque characteristic that resists vibration loosening.
STI taps and installation tools. Heli-Coil STI taps come in hand, machine and combination configurations for preparing holes to accept Heli-Coil inserts, alongside installation tools (drivers and mandrels) for correct insert engagement and notch-break removal of the installation tang. Both are essential companions to the inserts for correct installation.
Spark plug thread repair inserts. Specialist Heli-Coil spark plug thread repair kits restore damaged M14x1.25 and M18x1.5 spark plug threads in aluminium cylinder heads, one of the most common thread repairs in automotive maintenance. They are available in standard and long-reach configurations to match different head designs.
Industries
Heli-Coil thread inserts and repair kits are used in automotive and motorsport engineering, aerospace and defence manufacturing, commercial vehicle maintenance, marine engineering, general precision engineering, industrial equipment manufacture, electronics and instrumentation assembly, and any job involving threaded fasteners in aluminium, magnesium or other soft materials where thread strength or repair is a requirement.
Product Categories
- Thread repair kits (metric & imperial)
- Standard & tangless inserts
- STI taps & installation tools
- Spark plug thread repair kits
Good to Know
A stripped thread in an aluminium component does not have to mean replacing the whole component. A Heli-Coil repair, correctly installed, restores the thread to full original specification and is often stronger than the original. If you are dealing with a stripped spark plug thread or a stripped engine bolt hole, get in touch with the thread size and we’ll supply the right repair kit.
Buy Heli-Coil from The Tool & Gauge Company (UK) Limited
The Tool & Gauge Company (UK) Limited supplies Heli-Coil wire thread inserts for thread repair and reinforcement to trade customers, contractors and businesses across the UK and internationally. We order directly from Heli-Coil and their authorised distributors, and can source products across the full range to order. We deliver to any UK mainland address and export to the Middle East, Africa, Asia and beyond.
To enquire about Heli-Coil products, send us a part number, product name or description and we’ll come back with availability and a price, usually the same working day. We supply Heli-Coil thread repair kits, Heli-Coil insert kits for metric threads and Heli-Coil installation tools to UK engineering workshops and maintenance teams. Trade accounts with 30-day credit terms are available for qualifying businesses. Get in touch and we’ll take it from there.
Get in Touch
Send us your requirement and we’ll come back with a price. We aim to respond the same working day.