STI HexTap V-COIL rapid machine tap Form D HSS-G - STI-UNC 5/16x18

• For STI inserts according to ISO 2 (6H)
• For free-machining steels up to 900 N/mm²
• For unalloyed and low-alloy steels
• For hand tools or cordless screwdrivers with 1/4'' shank
• Suitable for blind and through holes
• Compatible with all 1/4'' bit holders

• Precise production of STI internal threads
• Suitable for blind and through holes
• Optimized chip evacuation thanks to Form D
• Long tool life due to high-quality HSS-G grinding
• 1/4'' hex shank – no adapter required
• Perfect for workshop, service, and repair

1. 1. Preparation: Drill the core diameter, countersink, clean.
2. 2. Align: Position the tap exactly perpendicular.
3. 3. Tapping: Cut the thread evenly – by hand or with low torque.
4. 4. Check: Inspect the thread and insert the STI insert.

• Form: D
• Material: HSS-G
• Tolerance: ISO 1 (4H)
• For inserts according to: ISO 2 (6H)
• Size: STI-UNC 5/16 × 18
• Overall length (L1): 42 mm
• Thread length (L2): 21 mm
• Diameter (B): 9.8 mm
• Drive: 1/4'' hex shank
• Article number: 03421

• 1 × STI HexTap V-COIL rapid tap STI-UNC 5/16 x 18 (Art. 03421)

Tip: Detailed information about difficult threads:
HexTap – The solution for difficult threads

What is an STI thread?
An STI thread is an oversized internal thread used to hold wire thread inserts – ideal for thread repair and reinforcement.

What does Form D mean?
Form D provides optimized chip evacuation and is suitable for both blind and through holes.

How is the tap used?
Via the 1/4'' hex shank – ideal for hand tools and cordless screwdrivers.

Which materials is it suitable for?
For free-machining steels up to 900 N/mm² as well as unalloyed and low-alloy steels.

Which tolerances apply?
The tap corresponds to ISO 1 (4H); the finished STI thread with insert corresponds to ISO 2 (6H).