Heli-coil 4986-10 Hand Sti Tap M10 X 1 Metric Fine

Product Description

The HELI-COIL 4986-10 is a hand STI tap designed for cutting M10 x 1 metric fine threads in preparation for Heli-Coil screw thread insert installation. Built from high speed steel with a bright finish, this tap features a bottoming chamfer and 4 flutes, making it well suited for threading to the bottom of blind holes. The D3 thread limit and 5H class of fit provide the tight tolerance required for reliable insert seating. With an overall length of 80.71 mm and a thread length of 36.51 mm, it handles typical insert-depth requirements in a compact, hand-driven format. Licensed tradespeople and skilled machinists rely on this tool for thread repair and new thread creation in production and field service environments.

This tap is used wherever M10 x 1 metric fine threaded inserts are installed, including thread repair work on engine components, machinery housings, and structural assemblies. The bottoming chamfer allows threading into shallow or blind holes where a taper or plug chamfer cannot reach the full thread depth. Compatible material applications include aluminum, magnesium, mild steel, and stainless steel, covering a wide range of field and shop repair scenarios across automotive, industrial, and general mechanical trades.

Key Features

• M10 x 1 metric fine thread form with D3 thread limit and 5H class of fit for precision insert fitment
• Bottoming chamfer enables threading to the base of blind holes
• 4-flute geometry promotes chip evacuation and cutting stability
• High speed steel construction withstands repeated use across aluminum, magnesium, mild steel, and stainless steel
• Bright finish for corrosion resistance during storage and use
• Shank diameter of 8.2 mm fits standard tap wrenches and holders

Compatibility

Designed for use with Heli-Coil screw thread insert systems requiring an M10 x 1 metric fine tapped hole. Suitable for insert installation in aluminum, magnesium, mild steel, and stainless steel workpieces as specified by the manufacturer.

Installation Notes

This tap is intended for hand operation using a tap wrench; power driving is not recommended without verifying appropriate speed and torque controls. Always secure the workpiece before tapping and apply cutting fluid appropriate to the base material, particularly when working with stainless steel or aluminum. Back the tap out periodically to break chips and prevent binding. Follow the insert manufacturer's depth and thread engagement specifications to ensure proper insert retention.