Heli-coil 3747-20 Thread Insert Tool M20 X 2.50

Product Description

The HELI-COIL 3747-20 is a hand installation tool designed to drive threaded wire inserts into pre-tapped holes. It accepts M20 x 2.50 metric coarse inserts and provides the controlled torque needed to seat each insert flush and true without damaging the host material. The tool is sized specifically for the M20 thread series, ensuring proper engagement with the insert tang during installation. Technicians in HVAC, plumbing, and general mechanical service use this tool when repairing stripped threads in aluminum, cast iron, or steel housings and equipment enclosures.

This tool is used wherever HELI-COIL wire thread inserts must be installed by hand rather than by powered tooling. Typical applications include field repairs on threaded bosses in compressor housings, pump bodies, manifolds, and structural brackets. It is suited for low-volume or single-repair work where a hand driver is the practical choice. The M20 x 2.50 size covers metric coarse applications in heavy equipment, large-diameter fittings, and industrial assemblies.

Key Features

• Sized for M20 x 2.50 metric coarse thread inserts
• Hand-drive design allows controlled installation without power tools
• Insert tool type engages the insert tang for precise seating depth
• Compact tool format suits field service and confined-space repairs
• Compatible with standard HELI-COIL M20 x 2.50 wire inserts

Compatibility

Designed for use with M20 x 2.50 metric coarse thread wire inserts. Intended for hand installation of HELI-COIL inserts in any host material pre-tapped to the M20 x 2.50 metric coarse specification.

Installation Notes

A licensed mechanic or qualified technician should ensure the host hole is properly drilled and tapped to the correct HELI-COIL specification before inserting. Power down or depressurize any equipment before beginning thread repair work. Apply steady, even torque when driving the insert to avoid cross-threading or over-seating. After installation, use a tang break-off tool to remove the drive tang if required by the insert design.