HELI-COIL

The tolerance designation on HELI-COIL STI taps indicates the pitch diameter tolerance of the tap. H2/4H and H3/4H refer to the class of fit for the tap relative to the insert thread. H2/4H provides a tighter tolerance, typically used for applications requiring a more precise thread fit, while H3/4H offers a slightly looser tolerance, allowing for easier insertion of the HELI-COIL insert. The choice depends on the material being tapped and the desired thread engagement. For example, H2/4H is common for harder materials, while H3/4H may be used in softer materials to reduce tap breakage.

Yes, HELI-COIL STI taps are available with different chamfer types to suit both through holes and blind holes. Plug chamfer taps (typically 3-5 threads of chamfer) are suitable for through holes or blind holes with sufficient clearance. Bottoming chamfer taps (1-2 threads of chamfer) are designed for blind holes where the tap must cut threads close to the bottom. The product listings for HELI-COIL taps from 3G Electric specify the chamfer type, such as plug chamfer, to help select the correct tap for the application.

HELI-COIL STI taps are typically manufactured from high-speed steel (HSS) or cobalt high-speed steel (HSS-E) to provide wear resistance and cutting performance. The taps are ground to precise tolerances and may have surface treatments like steam oxide or nitride coating to reduce friction and extend tool life. The specific material and coating depend on the tap size and intended application. For general-purpose tapping in materials like aluminum, steel, or cast iron, HSS taps are standard. For harder materials or higher production runs, cobalt or coated taps may be specified.

To select the correct HELI-COIL STI tap, you need to match the tap's thread size and pitch to the insert's thread specification. For example, an M12x1.75 insert requires an M12x1.75 STI tap. The tap's tolerance class (e.g., H3/4H) should correspond to the insert's thread class (e.g., 4H for metric inserts). HELI-COIL provides a tap selection guide that cross-references insert part numbers with tap part numbers. 3G Electric's product listings include the tap's thread size, pitch, and tolerance, allowing you to verify compatibility with your insert. For inch threads, ensure the tap matches the insert's UNC or UNF designation.

Yes, 3G Electric stocks HELI-COIL STI taps in both metric and inch sizes. Metric sizes include M4x0.7, M6x1, and M12x1.75, while inch sizes include #6-32 UNC, #10-32 UNF, 7/16-14 UNC, 7/16-20 UNF, and 9/16-18 UNF. These taps cover a range of common thread sizes used in industrial applications. The product listings specify the thread form (UNC, UNF, or metric) and the tap's tolerance class, enabling selection for various insert types.

Yes — 3G Electric (S) Pte. Ltd. supplies HELI-COIL products. We stock the HELI-COIL catalog and supply genuine factory-original products with full manufacturer warranty and technical support.