V-COIL Thread Repair Workshop Kit
Stripped or damaged internal thread? Repair it permanently – M5 to M12.
Everything you need to restore damaged internal threads in one compact kit: stainless steel wire thread inserts, STI taps, drill bits, installation tools and tang break-off tools.
What this kit does for you
The V-COIL Thread Repair Workshop Kit M5–M12 covers the most common metric thread sizes for fast, reliable and permanent thread repair.
All sizes M5 – M12
The five most common metric thread sizes in one assortment – ready for the majority of automotive and industrial repair jobs.
Stainless steel inserts
Wire thread inserts to DIN 8140 / ISO 2 (6H) from corrosion-resistant stainless steel for high-strength, durable threads.
Complete tooling included
STI drill bits, STI taps, hand installation tools and tang break-off tools – every tool needed is in the case.
Works on aluminium and steel
Especially effective on aluminium components where threads strip easily under repeated assembly cycles.
Organised plastic case
Functional, clearly labelled storage box for the workshop bench or service vehicle – everything has its place.
Repair, don't replace
Restore stripped threads in housings, engine components, bodywork and more – often saving the entire part.
What is inside the Workshop Kit?
A complete, self-contained assortment for professional thread repair – no additional tools required.
Internal threads wear out or strip – especially in aluminium components with frequent assembly cycles. Instead of scrapping the part or machining an oversized bore, the V-COIL Thread Repair Workshop Kit lets you cut a new, defined receiving thread and install a stainless steel wire insert that is at least as strong as the original – often stronger.
The kit (Art.-No. 04081) contains everything needed to repair the five most common metric sizes:
Kit contents at a glance
All components for M5, M6, M8, M10 and M12 thread repair – 110 inserts included.
🔩 Thread Inserts (Type S, 1.5D)
- 25× M5 × 0.8 wire thread inserts
- 25× M6 × 1.0 wire thread inserts
- 25× M8 × 1.25 wire thread inserts
- 25× M10 × 1.5 wire thread inserts
- 10× M12 × 1.75 wire thread inserts
🔧 STI Taps (Form D, HSS-G)
- 1× STI tap M5 × 0.8
- 1× STI tap M6 × 1.0
- 1× STI tap M8 × 1.25
- 1× STI tap M10 × 1.5
- 1× STI tap M12 × 1.75
🪛 STI Drill Bits
- 1× 5.2 mm STI drill bit (M5)
- 1× 6.3 mm STI drill bit (M6)
- 1× 8.3 mm STI drill bit (M8)
- 1× 10.4 mm STI drill bit (M10)
- 1× 12.4 mm STI drill bit (M12)
🛠 Installation & Break-Off Tools
- 5× Hand installation tools (No. 8, 9, 11, 13, 15)
- 5× Tang break-off tools (No. 8, 9, 11, 13, 15)
- Compact, labelled plastic storage case
Video tutorials
Watch the full repair in the unboxing and how-to video – or select your preferred language for the short repair overview.
See what's in the kit – and how it works
This video walks through the complete kit contents and demonstrates the full repair process from start to finish: drilling, tapping, inserting and checking the thread.
Ideal for first-time users or workshops evaluating the kit for their tool inventory.
The short repair video is available in five languages. Select the one that works best for you or your team.
Repair process in 60 seconds
This short clip shows the key steps of a V-COIL thread repair: pilot drilling, tapping the STI receiving thread, installing the wire insert and breaking off the drive tang.
Perfect to follow along at the workbench or to share with your team.
Step-by-step instructions
The following sequence covers the standard repair procedure. Always follow the vehicle or equipment manufacturer's specifications.
-
Prepare the damaged thread area.
Clean the bore and the surrounding area. Inspect the damaged thread to confirm the bore is accessible and the material is in good condition. -
Drill the STI pilot hole.
Select the STI drill bit that matches the thread size from the kit and drill the receiving bore to the correct diameter. Use the appropriate drill chart – the STI diameters are slightly larger than standard core holes. -
Cut the STI receiving thread.
Using a ratchet or tap wrench, cut the STI thread into the bore with the matching STI tap from the kit. Back off regularly to break chips, especially in blind holes. -
Select and install the wire thread insert.
Choose the correct insert for the size and length (1.5D = 1.5× nominal diameter). Wind it into the bore using the matching hand installation tool under light pressure until the insert sits flush or slightly below the surface. -
Break off the drive tang.
Use the tang break-off tool from the kit to snap off the lower drive tang. In blind holes the tang must always be removed so it cannot interfere with the bolt. -
Test the repaired thread.
Thread a standard bolt of the correct size by hand to verify smooth running and correct engagement depth. Check that the insert is seated correctly and does not rotate.
Note: For specific materials or non-standard thread depths always consult the technical data sheet or contact VÖLKEL technical support.
Safety & good practice
- Wear safety glasses when drilling and tapping – especially with aluminium swarf.
- Use cutting oil when tapping steel components for cleaner threads and longer tap life.
- In blind holes, always count the insert coils to ensure the insert does not protrude.
- Never reuse a drive tang that has been broken off – always use a fresh insert.
- Check the repaired thread at the next scheduled service or maintenance interval.
Visual guide: kit to finished thread
From the open case to the completed repair – these images show the key stages of the process.
Kit overview – open case
All components organised in the plastic case: inserts, taps, drill bits, installation tools and tang break-off tools.
Compact closed case
The kit closes securely for clean storage on the workshop shelf or in the service vehicle.
Technical & practical benefits
A professional kit for workshops, maintenance teams and assembly lines who repair rather than replace.
Equal or greater thread strength
Stainless steel inserts to DIN 8140 create a thread that matches or exceeds the load capacity of the original.
Corrosion and temperature resistance
The stainless steel insert protects the thread from corrosion and performs reliably across a wide temperature range.
Saves parts and cost
Repairing stripped threads instead of replacing housings, blocks or structural parts reduces material cost significantly.
Fast turnaround
A typical repair takes minutes, not hours – reducing downtime in production, service and maintenance environments.
Multi-language video support
Short repair videos available in English, Arabic (Egypt), Arabic (MSA), Thai and Turkish for international teams.
Part of the V-COIL system
Complements the full V-COIL range for automotive thread repair, including the Oil Drain Threads Repair Kit and spark plug kits.
Frequently asked questions
Short answers to common questions about the V-COIL Thread Repair Workshop Kit.
The kit (Art.-No. 04081) covers M5, M6, M8, M10 and M12 – the five most common metric thread sizes in automotive, mechanical engineering and industrial maintenance applications.
Yes – this is one of the most common applications. The stainless steel wire insert creates a harder, more durable thread in aluminium than the parent material, and greatly extends the service life of the repaired bore.
When installed correctly the V-COIL insert provides a thread that is at least equal in strength to the original – in soft materials like aluminium it is typically stronger. The stainless steel insert conforms to DIN 8140.
No special tools are required beyond a standard hand drill and a ratchet or tap wrench. All thread-specific tooling – STI drill bits, STI taps, hand installation tools and tang break-off tools – is included in the kit.
After breaking off the drive tang, thread a standard bolt in by hand to verify smooth running and correct engagement. Confirm the insert does not rotate when the bolt is removed. Check again at the next maintenance interval.