STI Hand Tap ISO 529 HSS-G - UNF 1.3/8 x 12

• for cutting the oversize STI receiving thread before installing a V-COIL wire thread insert
• for UNF 1.3/8 x 12 when the insert system, pitch, and original thread specification match
• for STI tapping after the repair drilling operation has been completed
• for preparation of receiving threads for wire thread inserts in thread repair work
• Process: manual driving or assisted driving depending on your holder and machine setup
• Use: thread cutting, re tapping, and thread cleaning depending on condition

Note Match STI tools to the wire thread insert system and do not use an STI tap as a standard finished-thread tap.

• STI geometry is intended for the receiving thread used by wire thread inserts rather than a standard finished thread.
• The stated material and standard data support controlled selection for professional thread repair.
• The thread designation UNF 1.3/8 x 12 helps you match tap, insert, and original thread requirement.
• Using a dedicated STI tap reduces the risk of installing the insert in an incorrectly sized receiving thread.

• An STI tap is not suitable for producing a standard internal thread, so use a normal tap when no insert repair is planned.

1. Identify the original damaged thread and select the matching V-COIL insert system.
2. Prepare the hole with the required repair drilling step before tapping.
3. Clamp the STI tap in a suitable holder or machine setup with correct alignment.
4. Cut the STI receiving thread using the workshop process for the material and hole type.
5. Clean the receiving thread before inserting the wire thread insert.
6. Install the matching V-COIL insert with the appropriate inserting tool.
7. Remove the tang where the repair process requires it.
8. Inspect the repaired thread before returning the component to service.

• 1 piece STI Hand Tap ISO 529 HSS-G - UNF 1.3/8 x 12

• Product type: STI hand tap
• Thread system: STI-UNF
• Thread designation: UNF 1.3/8 x 12
• Standard: ISO 529
• Material: HSS-G
• Tolerance: 3B
• Direction: RH
• Package quantity: 1
• Overall length: 150
• Square size: 22.4

Is this tap for a standard finished internal thread?

No, it cuts the oversize STI receiving thread used before a V-COIL wire thread insert is installed.

How do you choose the correct STI tap?

Choose the STI tap by the original thread, insert system, thread designation UNF 1.3/8 x 12, tap form, and hole type in the workpiece.

Why does STI selection differ from normal tapping?

STI tapping prepares the receiving thread for the insert, while the installed insert later provides the usable finished thread for the screw.

What should you check before using the STI tap?

Check the drilling step, alignment, insert type, hole depth, and whether the selected tap form fits through-hole or blind-hole work.

Where can you find V-COIL repair information?

Additional V-COIL repair guidance is available here: Technical information V-COIL thread repair as PDF

Can this tap replace an inserting tool?

No, the STI tap cuts the receiving thread, while a separate inserting tool drives the wire thread insert into that thread.

Where can you find the V-COIL catalog?

You can find the thread repair catalog here: VC 23 catalog as PDF