Hertel K008251AS Spiral Flute Tap 10-24 Unc Hss

Product Description

The HERTEL K008251AS is a spiral flute tap designed for cutting internal threads in through-holes and blind holes where chip evacuation is a priority. Built from high-speed steel (HSS) with a fast flute style and a 52-degree helix angle, this tap pulls chips up and out of the hole rather than pushing them forward. It cuts a 10-24 UNC right-hand thread to a Class 2B/3B fit tolerance at H3 limit. The plug chamfer provides a gradual lead-in suited for general-purpose tapping in a range of materials. Overall length is 2.375 inches, and the tool weighs 0.24 pounds. Machinists, toolmakers, and maintenance technicians rely on this geometry for clean, consistent threads in production and repair work.

This tap is applied in situations where a 10-24 UNC thread is required in through-holes or moderately deep blind holes. The spiral flute design and fast helix angle make it particularly effective in materials that produce stringy chips, such as aluminum, mild steel, and stainless steel, where a straight flute tap would pack chips into the flute. It is suited for use in CNC machining centers, drill presses, and hand tapping operations. The 3-flute configuration balances chip volume and tool strength at this thread size. The H3 thread limit accommodates standard 2B and 3B class-of-fit requirements found in most general mechanical assemblies.

Key Features

• 52-degree helix angle with fast flute style for efficient chip extraction in through-hole and blind-hole applications
• High-speed steel construction provides wear resistance and performance across a broad range of work materials
• Plug chamfer lead-in (3-5 threads) for general-purpose tapping where the tap can be started from a chamfered or drilled entry
• H3 thread limit for Class 2B/3B fit - compatible with standard mechanical assembly tolerances
• Right-hand thread direction, right-hand flute - standard orientation for conventional tapping spindles
• No coolant-through feature; suitable for flood coolant or manual lubrication

Compatibility

Designed as an OEM-style replacement or direct production tap for any application requiring a 10-24 UNC internal thread with a Class 2B/3B fit at H3 tolerance limit.

Installation Notes

Secure the tap in an appropriate tap holder or floating tap collet to prevent breakage from misalignment. Always use a cutting fluid or tapping compound appropriate to the work material before starting the tap. Ensure the pilot hole is drilled to the correct tap drill diameter for a 10-24 UNC thread per standard machinists references. Back the tap out periodically to clear chips when tapping by hand, and never force a tap that has stopped rotating freely.