What Are Thread Repair Kits?
Thread repair kits are complete sets that restore damaged or stripped internal threads in metal parts. Our E-Z LOK E-Z Coil kits include the correct drill bit, tap, installation tool, and helical wire inserts so you can cut a fresh thread and install a stainless steel coil that provides durable, wear-resistant machine threads.
Why Choose E-Z LOK E-Z Coil Thread Repair Kits?
- Everything included: drill, tap, driver, and a selection of inserts.
- Stronger in soft metals: stainless coil distributes load, improving pull-out strength in aluminum, magnesium, and cast alloys.
- Precise & repeatable: dedicated tooling keeps alignment true for clean, professional repairs.
- Inch & metric options: common coarse, fine, and metric threads for maintenance shops and production repair.
- Cost-saving: repair the component in minutes instead of replacing castings, housings, or brackets.
How a Helical Thread Repair Works
- Drill: Enlarge the damaged hole with the included drill bit.
- Tap: Use the supplied tap to cut the insert’s special thread.
- Install: Load a coil on the driver and turn it in until 1/4–1/2 turn below the surface.
- Break tang: Snap off the tang with the breaker tool for through-fastener clearance.
Where Thread Repair Kits Are Used
- Automotive & powersports: aluminum engine covers, brackets, and accessories.
- Machinery maintenance: cast housings, fixtures, jigs, and tooling.
- Aerospace & electronics: thin or soft metal components needing durable machine threads.
- General fabrication: any shop task where a removable fastener must be reliably re-installed.
Selection Tips
- Match the fastener size: choose the kit for the bolt size you want to use (e.g., 1/4-20, M6x1.0).
- Check depth: pick an insert length that provides at least 1.0–1.5× bolt diameter of thread engagement.
- Material compatibility: stainless inserts are ideal for aluminum and most steels; use cutting fluid when tapping harder materials.
Thread Repair Kits — FAQ
Are repaired threads as strong as the original?
In soft metals (aluminum, magnesium, cast zinc), a stainless helical insert often delivers greater pull-out strength and wear resistance than the original tapped hole.
Do the kits include the right drill and tap?
Yes. Each kit includes the matched drill size and special tap required for the insert thread form, plus an installation tool and a starter assortment of inserts.
Can I use these in blind holes?
Yes. Install the coil to the proper depth and break the tang with the provided tool. Ensure there is enough bottom clearance for the tap and insert length.
How do I choose insert length?
A general rule is 1.0–1.5× the bolt’s diameter of internal thread engagement for full strength (example: 3/8" bolt → 3/8"–9/16" of insert length engaged).
What if I installed an insert too high or too low?
Back it out using a removal tool (or a small pick engaging the coil end) and reinstall at the correct depth. Coils are serviceable and replaceable.
Will threadlocker or anti-seize affect the repair?
You can use standard thread treatments on the bolt after installation. Avoid adhesives on the insert during install unless specified; the coil is designed to lock into the tapped housing mechanically.
What torque can I apply after repair?
Use the same torque you would for the original fastener in the parent material, provided you have the recommended engagement length and clean, properly installed insert.