Helicoil®

Heli-Coil has the most effective & universally accepted method of thread repair. Heli-Coil inserts quickly & permanently restore stripped, worn or damaged threads to their original size & condition.

The inserts work in any part or material, aluminum, magnesium, cast iron, bronze, etc. The use of light weight (& soft) materials in fuel efficient cars means more thread damage... there is a Heli-Coil insert to repair virtually every application. 

Damaged threads can be restored to better than new condition in spark plug ports, carburetor fuel inlets, transmission housings, oil drain plugs, exhaust and intake manifolds, head bolt holes, brake calipers & more! The Help-Coil system makes all other thread repair methods obsolete: 

welding, plugging, oversized fasteners & oversized drilling of mating parts. It's faster - you save time, increase your shop's repair capabilities & restore parts that otherwise would have to be scrapped.

Heli-Coil repairs are available in the following standard thread series & size ranges:

Inch Coarse (#8 thru 1-1/2), Inch Fine (#10 thru 1-1/2), Metric Coarse (M3 thru M20), Metric Fine ( M8 thru M18), Spark Plug (10mm, 12mm, 14mm, 18mm & 7/8"), & Pipe Thread (1/8" thru 1").

In addition to the above, custom sizes are available for various repairs. 

DRILL

Drill out the damaged threads using the drill size specified on the kit or set. Drill to sufficient depth to accommodate the insert length & bolt or screw being used.

TAP

Use the Help-Coil tap supplied in the kit or set. Check the size on the shank to make sure you have the right one. Tap the hole to sufficient depth to accommodate the insert length & bolt or screw being used.

INSTALL 

Use the installation tool supplied in the kit or set. Just wind the insert into the hole until the top coil is 1/4-1/2 turn into the tapped thread. Now you're back to the original size & the original size fastener can be used.

TANG REMOVAL

The tang must be removed to allow full passage of the bolt or screw through the insert. Place square (unchamfered) end of a punch on the tang & strike sharply. For inserts over 1/2", M14 & up, & all spark plug sizes, use long nose pliers. Holding the tang with the pliers, bend it alternately in & out until it comes free.

Note: For Spark Plug repairs, NO drilling is necessary. The Help-Coil spark plug kit contains a piloted reamer tap. With this tap, the damaged threads are removed & new threads are cut in one continuous operation.