Thread Repair Guide
Which type of thread repair is best for your application? This guide will help you choose the right solution.
Understanding Thread Damage
Thread damage occurs in several ways, and understanding the cause helps determine the best repair method:
Stripped Threads
Cross-threading, over-torquing, or repeated removal damages thread form.
Corroded Threads
Chemical corrosion or rust deteriorates thread integrity.
Worn Threads
Repeated use, especially in soft materials, wears threads beyond tolerance.
Cracked Parent Material
Material fatigue or stress causes cracks around threaded holes.
Thread Repair Solutions Comparison
Time-Sert
Best For: Aluminum engine blocks, cylinder heads, critical applications requiring maximum strength and permanence.
Advantages:
- Permanent installation
- Stronger than original thread
- Excellent vibration resistance
- Thin-wall design maximizes engagement
Considerations:
- Requires counterbore tool
- Higher initial cost
- More installation steps
- Professional quality results
Big-Sert
Best For: Oversized damage, spark plug threads, when standard inserts won't fit.
Advantages:
- Repairs oversized holes
- Same benefits as Time-Sert
- Ideal for spark plugs
- Maximum strength repair
Considerations:
- Requires larger drill size
- Removes more parent material
- Specialized application
- Professional installation recommended
Helicoil/NuCoil
Best For: General purpose repairs, steel and cast iron, cost-sensitive applications.
Advantages:
- Lower cost per insert
- Stronger than original thread
- Wide size availability
- Industry standard
Considerations:
- Can work loose in high vibration
- Not as strong as solid inserts
- Limited reusability once damaged
- Tang removal required
Keenserts
Best For: Self-locking requirements, soft materials, aerospace applications.
Advantages:
- Key Self-locking design
- Excellent in soft metals
- Vibration resistant
- High pull-out strength
Considerations:
- Keys penetrate parent material
- Can crack brittle casing
- Limited sealing ability
- Not ideal for sparkplugs & sump plugs
Decision Matrix
| Application | Recommended Solution |
|---|---|
| Aluminum cylinder head threads | Time-Sert |
| Spark plug thread repair | Time-Sert or Big-Sert |
| Steel engine block | Helicoil or Time-Sert |
| High vibration environment | Time-Sert or Keensert |
| Budget-conscious repair | Helicoil |
| Oversized hole damage | Big-Sert, Keensert, Loc-in-Sert |
| Aerospace/critical application | Keensert or Time-Sert |
| General purpose steel repair | Helicoil |
Still Have Questions?
Our technical team can help you select the perfect thread repair solution for your specific application.