Hand Tap set of 3 pieces DIN 352 HSS-G - BSW 9/16 x 12

A 3-piece set is the classic and most complete solution for manual thread cutting. It consists of three coordinated tools that each cut a specific part of the thread:

• Taper Tap (Chamfer A): The first tap in the set with the longest chamfer (approx. 6-8 threads). It starts the thread and only pre-cuts it.
• Second Tap (Chamfer C): The second tap with a shorter chamfer (approx. 3-4 threads). It deepens the pre-cut thread.
• Bottoming Tap (Chamfer C): The third tap with a short chamfer (approx. 2-3 threads). It cuts the thread to the final depth and the correct profile. It is especially important for cutting the thread all the way to the bottom of a blind hole.

Each tap is usually identified by one, two, or no ring marks on the shank.

BSW Thread: The abbreviation stands for "British Standard Whitworth." This is a coarse thread with a flank angle of 55°. It is often used for robust connections where strength is the priority. The nominal size BSW 9/16 x 12 means that the outer diameter is 9/16 inches and there are 12 threads per inch (tpi).

DIN 352: This standard specifies the exact dimensions, chamfer lengths, and tolerances for hand tap sets. By adhering to this standard, it is ensured that all three taps work together perfectly to create a precise and standard-compliant thread.

The correct procedure is crucial for a successful result. Here is a simple guide:

• Prepare: Drill the pilot hole to the correct diameter for the BSW 9/16 thread. A correct pilot hole is essential for thread quality.
• Secure and Clamp: Secure your workpiece. Take the taper tap and clamp it into a suitable tap wrench.
• Pre-cut: Begin to turn the tap perpendicular to the workpiece. Turn it two turns forward and half a turn back to break the chips. Cut the thread until you feel resistance.
• Second Cut: Replace the taper tap with the second tap. Repeat the process with the same turning and chip-breaking technique.
• Finish Cut: Finally, use the bottoming tap. Cut the thread to the final depth. For a blind hole, this tap ensures that the thread is cut completely to the bottom.

What does the material HSS-G mean?

HSS-G stands for "High Speed Steel - Ground." The "G" means that the cutting surfaces are precision ground. This leads to higher cutting accuracy, better surface quality of the threads cut, and an increased tool life compared to unground taps (HSS-R).

What is the difference from a machine tap?

Hand taps like this set are optimized for manual use with a tap wrench. Machine taps are designed for use in a machine and often have a different geometry (e.g., a spiral flute or spiral point) to discharge chips more efficiently.

What materials is this set suitable for?

This set is designed for general use in well-machinable materials up to 900 N/mm². This includes unalloyed and low-alloy steels.

How do I know which tap in the set is the taper tap?

The taps in a 3-piece set are marked with ring grooves on the shank end: The taper tap has one ring, the second tap has two rings, and the bottoming tap has no rings.

Can I also cut a thread without the complete set?

For through holes, you can usually use the taper and second tap. However, for blind holes, the bottoming tap is essential to cut the thread completely to the bottom. For a standard-compliant, complete thread, it is always recommended to use all three taps.