Thread Repair Kits, UNC 7/16 - 1,5D

• for repairing damaged or worn UNC internal threads 7/16 x 14
• for reinforcing threads in materials with low shear strength
• for recovering components with damaged internal threads
• for creating new load-bearing internal threads with Type S wire thread inserts
• for service workshops, maintenance, assembly, metalworking and mechanical engineering
• Process: manual or assisted drive depending on your tool holder and machine configuration
• Use: thread cutting, thread reworking and thread cleaning depending on the condition of the thread

Note Before repairing the thread, check the thread designation, component condition, available wall thickness and required insert length so the wire thread insert seats securely in the receiving thread.

• complete kit logic with drill, STI tap, inserting tool, tang break tool and inserts
• stainless steel wire thread inserts create a load-bearing internal thread in the repaired component
• Type S is free running and suitable for standard screw connections without locking function
• DIN 8140 and ISO 2 (6H) support a repair process based on recognized standards
• the component-based kit structure reduces incorrect tool selection during the repair workflow
• the kit is suitable for recurring service work on inch-based UNC threads

• The repair is reliable only when drilling, STI receiving thread and insert depth are executed cleanly, so the kit components should be used in the correct sequence.

1. Inspect the damaged internal thread and decide whether the component structure allows a repair with a wire thread insert.
2. Align the component securely and make sure the tool axis and thread axis are in line.
3. Drill out the damaged thread area with the STI twist drill included in the kit.
4. Cut the STI receiving thread with the matching STI tap and suitable cutting fluid.
5. Clean the receiving thread and remove chips completely from the repair area.
6. Place the wire thread insert into the hand inserting tool and guide it straight into the receiving thread.
7. Screw in the insert in a controlled manner until the intended installation position is reached.
8. Remove the driving tang with the tang break tool.
9. Check the thread run with a suitable screw or appropriate inspection tool.

• 1x STI short machine tap ISO 529 Form D HSS-G for UNC 7/16 x 14 VÖLKEL 03110
• 1x tang break tool No. 14 VÖLKEL 07014
• 1x inserting tool with locking collar No. 14 VÖLKEL 08014
• 10x wire thread inserts Type S, free running, UNC 7/16 x 14, 1.5 D VÖLKEL 08310
• 1x STI twist drill 11.6 mm VÖLKEL 00116

• Product class: thread repair
• Product type: V-COIL thread repair kit
• Thread system: UNC
• Nominal size: UNC 7/16 x 14
• Insert length: 1.5D
• Insert type: Type S, free running
• Standard reference of inserts: DIN 8140
• Insert tolerance: ISO 2 (6H)
• Insert material: stainless steel
• Tap: STI short machine tap Form D HSS-G
• Drill: STI twist drill 11.6 mm
• Inserting tool: inserting tool with locking collar No. 14
• Tang break tool: No. 14

What is this thread repair kit used for?
You use the kit to repair damaged UNC internal threads 7/16 x 14. The wire thread insert creates a new load-bearing internal thread in the prepared receiving thread.

What does UNC 7/16 x 14 mean?
UNC means Unified National Coarse, an inch-based coarse thread system. For correct selection, the thread designation on the component must match UNC 7/16 x 14.

Is the kit intended for internal or external threads?
The kit is intended for internal threads. External threads are not repaired directly with this V-COIL repair principle.

Why do you need an STI tap?
The STI tap cuts the special receiving thread for the wire thread insert. A standard tap for screw threads does not create the required geometry for this repair process.

Where can you find technical information about V-COIL thread repair?
The repair principle with a wire thread insert is explained in more detail here: Technical information V-COIL thread repair as PDF.

What should you check before installing the insert?
Check whether the receiving thread is cut cleanly and whether the insert can be started straight. Misalignment can affect the seating of the wire thread insert.

Where can you find information about wire thread inserts according to DIN 8140?
Further technical information about wire thread inserts according to DIN 8140 is available here: Technical information wire thread inserts DIN 8140 as PDF.

When is the 1.5D insert length suitable?
The insert length must match the thread repair and the available installation space. Before ordering, check whether the intended installation depth is available in the component.

Where can you find the V-COIL catalogue?
You can find the catalogue for thread repair and V-COIL system overviews here: VC 23 catalogue as PDF.