Machine Tap DIN 376 Form C 35° Spiral Flute HSSE - UNF 9/16 x 18

A machine tap is a tool for cutting internal threads. Unlike hand taps, it is optimized for use in drilling machines or CNC machines. Its geometry is designed to cut threads quickly and efficiently and to evacuate the resulting chips.

This model is suitable for use in well-machinable materials up to a strength of 900 N/mm², including unalloyed and low-alloy steels. Due to its specific design, it is particularly suitable for cutting threads in blind holes.

• UNF: Stands for "Unified National Fine." This refers to an American fine thread according to the ANSI B 1.1 standard.
• ANSI B 1.1: Is an American standard that specifies the dimensions and specifications for Unified Screw Threads.
• DIN 376: A German industrial standard that specifies the dimensions and specifications of taps for metric and imperial threads. It ensures that the tool complies with technical requirements.
• Form C 35° Spiral Flute: This describes the tool's geometry. Form C refers to the tap's lead chamfer, which has a relatively short lead of 2-3 threads. 35° Spiral Flute refers to the special spiral shape of the cutting edge geometry. This spiral pushes the chips forward and out of the drilled hole, which is ideal for blind holes.
• HSSE: Stands for "High-Speed Steel with Cobalt." This is an alloyed high-speed steel that offers higher hot hardness and wear resistance than pure HSS steel, which increases the tool's lifespan.
• Tolerance 2B: Refers to the thread tolerance. In the ANSI standard, tolerance class 2B indicates a medium tolerance range for internal threads, suitable for most standard applications.

Blind holes are drilled holes that do not go completely through a workpiece. The thread therefore ends at a certain point within the material. Machine taps with a spiral flute (Form C 35° Spiral Flute) are particularly well suited for blind holes because they push the chips out of the hole, thus preventing clogging.

Through holes, on the other hand, are holes that go completely through the workpiece. For these types of holes, taps with a straight flute or a left-hand spiral are often used, as the chips can be evacuated backwards through the hole.

For optimal use and a perfect thread, follow these steps:

1. Preparation: Select the right tool and ensure a clean, burr-free work environment. Make sure the core hole has the correct diameter (according to the UNF table for 9/16-18).
2. Clamping: Securely clamp the machine tap in the machine (e.g., drill chuck or collet).
3. Cutting: Start the machine at the recommended speed and feed rate. The tap will cut the thread into the hole.
4. Chip Evacuation: The 35° spiral flute reliably transports chips out of the blind hole. Use cutting oil if necessary to reduce friction and extend the tool's life.
5. Cleaning: After the cutting process, remove any remaining chips from the thread.

1. Can I also use this tap manually?

While technically possible, this tool is specifically optimized for machine use and is therefore not ideal for manual application.

2. What core hole diameter do I need for this thread?

The required core hole diameter for a UNF 9/16 x 18 thread is typically 13.5 mm or 0.531 inches.

3. What do "HSS" and "HSSE" mean?

HSS stands for "High-Speed Steel." HSSE is an improved version of it, which is additionally alloyed with cobalt, increasing its hardness and temperature resistance.

4. What is the difference between a UNF and a UNC thread?

Both are American Unified threads. UNF ("Unified National Fine") has a finer pitch and is used for applications with thinner wall thicknesses or high-strength requirements. UNC ("Unified National Coarse") has a coarser pitch and is suitable for general applications.

5. How do I find the correct speed for my machine?

The optimal speed depends on the workpiece material and the thread diameter. Manufacturer specifications and standard tables for cutting speeds provide the best guidelines for this.