High Speed Steel Spiral Flute STI Tap, #4-40 UNC, 2 Flute, 52° Helix, Bottoming Chamfer, Bright Finish, 2″ OAL

Description

Product Overview

The Hertel High Speed Steel Spiral Flute STI Tap #4-40 UNC is engineered for precision threading in demanding industrial environments. Featuring a 52° helix angle, the tap provides rapid chip evacuation, reducing torque and extending tool life. The spiral flute design, combined with a bright-finished HSS construction, ensures consistent cutting performance across a variety of materials, from aluminum alloys to hardened steels.

Measuring 2 inches in overall length with a 2‑flute configuration, this tap offers a compact profile that fits easily into tight spaces while delivering the strength required for deep blind hole applications. The bottoming chamfer is specially shaped to start the thread at the very bottom of a hole, guaranteeing a full, clean thread profile even in the most constrained conditions.

Each tap is manufactured to tight tolerances, delivering a thread geometry that meets or exceeds industry standards for UNC #4-40 specifications. The bright finish not only enhances visual inspection but also reduces friction, contributing to smoother operation and lower heat generation during high‑speed tapping cycles.

Designed for versatility, the tap is suitable for aerospace component assembly, automotive engine repair, and general manufacturing where reliable, repeatable threading is essential. Its robust HSS material resists wear and deformation, making it a cost‑effective choice for high‑volume production lines.

With a focus on durability and performance, the Hertel tap integrates seamlessly into existing toolsets, offering a plug‑and‑play solution for technicians and engineers seeking to improve productivity without compromising quality.

Usage

When working with blind holes, the bottoming chamfer allows the tap to initiate threading at the deepest point, eliminating the need for pre‑tapped pilot holes. This feature is especially valuable in aerospace assemblies where material thickness is limited and precision is paramount.

In automotive repair, the tap’s spiral flute efficiently removes chips from tight engine compartments, preventing chip re‑engagement that can damage surrounding components. The 52° helix angle reduces the required feed pressure, enabling faster cycle times on production benches.

For general manufacturing, the tap excels in creating consistent threads on fixtures, jigs, and custom brackets. Its 2‑flute design balances chip clearance with structural rigidity, ensuring stable operation even under high torque conditions.

Operators should use appropriate cutting fluid to maximize the bright finish’s lubricating properties, extending tool life and improving surface finish. The tap is compatible with standard tapping machines and manual hand taps, offering flexibility across different shop floor setups.

Safety considerations include wearing eye protection and ensuring the workpiece is securely clamped before tapping. The tap’s design minimizes the risk of breakage, but proper alignment and gradual feed are recommended for optimal results.

Why Choose Us

Hertel’s reputation for quality tooling is backed by rigorous testing and a commitment to continuous improvement. Each tap undergoes a multi‑stage heat treatment process that enhances hardness while preserving the bright finish for reduced friction.

Our after‑sales support includes technical assistance from experienced engineers who can help troubleshoot threading challenges, recommend optimal cutting parameters, and provide guidance on tool maintenance. This service ensures that customers achieve the highest possible productivity from their investment.

We source high‑grade HSS from certified suppliers, guaranteeing material consistency and performance across every batch. This attention to material quality translates into longer tool life and fewer replacements, delivering cost savings over the lifespan of the tap.

Environmental responsibility is also a priority; our manufacturing processes adhere to ISO 14001 standards, reducing waste and energy consumption while maintaining product excellence.

Key Features

• 52° helix angle provides fast chip evacuation for smoother tapping
• Spiral flute design reduces torque and extends tool life
• Bottoming chamfer creates full threads in blind holes without pilot holes
• Bright‑finished HSS construction offers low friction and high durability
• Comprehensive technical support and warranty for reliable after‑sales service

FAQ

What size tap does this product replace?

This tap is a #4‑40 UNC size with a 2‑inch overall length, matching standard specifications for UNC #4‑40 threading in blind holes.

Can this tap be used on hardened steel?

Yes, the high‑speed steel material and bright finish are designed to cut through hardened steels up to 45 HRC, provided appropriate cutting fluid is used.

What is the purpose of the bottoming chamfer?

The bottoming chamfer allows the tap to start threading at the very bottom of a blind hole, ensuring a complete and accurate thread profile without the need for a pilot hole.

How many flutes does the tap have and why does it matter?

The tap features a 2‑flute design, which balances chip removal efficiency with structural rigidity, delivering consistent performance in deep or narrow holes.

What support does Hertel provide after purchase?

Hertel offers technical assistance, tool maintenance guidelines, and a warranty that covers material defects, ensuring customers receive ongoing value and reliability.