Heli-coil 4944-12 Hand Sti Tap M12 X 1.25 Metric Fine

Product Description

The HELI-COIL 4944-12 is a hand STI (Screw Thread Insert) tap designed to cut M12 x 1.25 metric fine threads in preparation for HELI-COIL thread insert installation. Ground from high speed steel with a bright finish, this 4-flute plug chamfer tap produces a D4 thread limit with a 5H class of fit. The overall length is 91.28 millimeters with a thread length of 42.07 millimeters and a shank diameter of 10.90 millimeters. It is used by machinists, maintenance technicians, and field service professionals who need to repair or create threaded holes to accept wire thread inserts in a range of base materials.

This tap is suited for repair and manufacturing applications where stripped or damaged M12 x 1.25 metric fine threads must be restored using HELI-COIL inserts. The plug chamfer style makes it appropriate for through-hole and moderately deep blind-hole applications. It is commonly used in automotive, aerospace, and general industrial maintenance where insert-threaded repairs are required in aluminum, magnesium, mild steel, and stainless steel workpieces.

Key Features

• M12 x 1.25 metric fine thread form with D4 thread limit and 5H class of fit
• 4-flute plug chamfer geometry suits through-hole and moderately deep blind-hole tapping
• High speed steel construction provides durability across aluminum, magnesium, mild steel, and stainless steel
• Bright finish for visual wear monitoring during use
• Thread length of 42.07 millimeters and overall length of 91.28 millimeters
• Square drive tang with 8.18 millimeter square size for use with standard tap wrenches

Compatibility

Designed for use with HELI-COIL STI insert systems requiring an M12 x 1.25 metric fine tapped hole. Compatible with aluminum, magnesium, mild steel, and stainless steel base materials as specified by the manufacturer.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician familiar with thread repair procedures. Secure the workpiece before tapping and use appropriate cutting fluid for the base material, particularly when working with stainless steel or aluminum. Use a calibrated tap wrench sized for the 10.90 millimeter shank and 8.18 millimeter square drive. Follow the HELI-COIL system installation sequence: drill to correct tap drill diameter, tap with this STI tap, then install the wire thread insert using the correct insertion tool.