Stripped threads in automotive components, such as cylinder heads and engine blocks, can be a significant problem, often rendering the component unusable. Fortunately, there is a simple and effective solution known as a Helicoil insert. A Helicoil insert is a precision-engineered wire coil that is inserted into the damaged threads, creating a new, stronger thread that can withstand the rigors of automotive applications. Installing a Helicoil insert is a straightforward process that can be performed with a few basic tools.
To begin, the damaged threads must be drilled out to a slightly larger diameter than the Helicoil insert. This can be done using a drill bit that is the same size as the specified tap drill for the Helicoil insert. Once the threads have been drilled out, a tap is used to create the new threads for the Helicoil insert. The tap should be the same size and pitch as the Helicoil insert. When tapping the new threads, it is important to apply cutting oil to the tap to prevent it from seizing in the hole.
Once the threads have been tapped, the Helicoil insert can be installed. The Helicoil insert is typically installed using a special installation tool. The installation tool has a tapered end that is used to insert the Helicoil insert into the hole. The installation tool is then tightened, which causes the Helicoil insert to expand and engage with the new threads. Once the Helicoil insert is installed, the installation tool can be removed, and the new thread is ready to use.
Gathering Essential Tools and Materials
Tools
The first step in installing a Helicoil is gathering the necessary tools. These include:
- Helicoil Insert Kit: This kit contains the correct size helicoils, a tap, and an installation tool.
- Drill: A variable-speed drill is preferable for accurate drilling.
- Drill Bits: You will need the following drill bit sizes: the original hole size, a clearance hole size (slightly larger than the helicoil), and a tapping hole size (specified in the helicoil kit).
- Tap Handle: Used to guide the tap while threading the hole.
- Thread Lock: To secure the helicoil in place.
Materials
In addition to the tools, you will need the following materials:
- Helicoils: Pre-wound wire inserts of the correct size and length for the application.
- Cutting Fluid: To lubricate the drilling and tapping process.
- Cleaning Brush: To remove any debris from the hole before installation.
Helicoil Kit Contents
The following table outlines the typical contents of a Helicoil insert kit:
| Item | Quantity |
|---|---|
| Pre-wound Helicoils | 10-25 |
| Tap | 1 |
| Installation Tool | 1 |
| Drill Bit (Original Hole Size) | 1 |
| Drill Bit (Clearance Hole Size) | 1 |
| Drill Bit (Tapping Hole Size) | 1 |
Drilling the Oversized Hole
Once you’ve selected the appropriate Helicoil insert, it’s time to prepare the damaged thread. This involves drilling out the existing hole to a larger diameter to accommodate the insert.
To determine the correct drill size, refer to the manufacturer’s instructions provided with the Helicoil kit. Typically, it will involve using a drill bit that is slightly larger than the outer diameter of the chosen insert.
When drilling, it’s crucial to maintain a steady hand and drill at a right angle to the workpiece. Avoid drilling too deep, as this could weaken the base material. Use a drill stop or mark the drill bit to ensure you only drill to the specified depth.
Once the oversized hole is drilled, it’s essential to thoroughly clean it. Use a tap or compressed air to remove any metal chips or debris that could interfere with the installation of the Helicoil insert.
Drilling Size Chart
The following table provides approximate drill sizes for various Helicoil insert sizes:
| Helicoil Insert Size | Drill Size |
|---|---|
| M5 | 5.2 mm |
| M6 | 5.8 mm |
| M8 | 7.3 mm |
| M10 | 8.4 mm |
| M12 | 10 mm |
Tapping the Hole for the Helicoil Insert
Tapping the hole for the Helicoil insert is a critical step in the installation process. The tap should be the correct size for the insert you are using, and the hole should be tapped to the specified depth. If the hole is not tapped correctly, the insert will not be properly installed and may not provide the desired results.
To tap the hole, follow these steps:
1. Insert a drill bit into the drill press or handheld drill, and adjust the speed to the recommended setting for the material you are drilling.
2. Place the workpiece on a stable surface, and position the drill bit over the center of the hole.
3. Hold the drill perpendicular to the workpiece, and slowly begin to drill. Apply pressure gently, and let the drill do the work.
4. Drill to the specified depth for the Helicoil insert. The depth will vary depending on the size of the insert, so refer to the manufacturer’s instructions for the specific depth.
5. Once the hole is drilled, remove the drill bit and blow out any chips or debris from the hole.
| Insert Size | Drill Bit Size | Tap Depth |
|---|---|---|
| M6 | 5.2 mm | 13 mm |
| M8 | 6.7 mm | 16 mm |
| M10 | 8.1 mm | 19 mm |
| M12 | 10.1 mm | 22 mm |
Finalizing the Installation
Once the helicoil is fully inserted into the hole, the next step is to finalize the installation. This involves the following steps:
9. Removing the Tang
The tang is a small piece of metal that protrudes from the end of the helicoil. It is used to guide the helicoil into the hole and secure it in place during installation. Once the helicoil is fully inserted, the tang must be removed.
To remove the tang, use a pair of pliers to bend it back and forth until it snaps off. Be careful not to damage the helicoil while removing the tang.
10. Inspecting the Installation
Once the tang is removed, inspect the installation to ensure that the helicoil is properly seated and secured. Make sure that there are no gaps or imperfections in the installation, and that the helicoil is level with the surrounding material.
If you notice any problems with the installation, remove the helicoil and start over.
11. Testing the Repair
To test the repair, insert a bolt into the helicoil and tighten it down. Make sure that the bolt threads smoothly into the helicoil and that it provides a secure hold.
If the bolt does not thread smoothly or if it does not provide a secure hold, the helicoil may not have been installed properly. Remove the helicoil and start over.
How to Install a Helicoil
Installing a Helicoil is a common repair technique used to restore damaged or stripped threads in a metal component. It involves inserting a wire coil into the damaged hole, which creates new threads that are stronger and more durable than the original ones. Here are the steps on how to install a Helicoil:
- Clean the damaged hole: Remove any debris or dirt from the hole using a tap or wire brush.
- Select the correct Helicoil size: Determine the size of the damaged hole and select a Helicoil that matches the inner diameter of the hole.
- Tap the hole: Use a tap to create new threads in the hole. The tap size should correspond to the outer diameter of the Helicoil.
- Insert the Helicoil: Place the Helicoil into the tap and use an insertion tool to screw it into the hole. The insertion tool should be slightly smaller than the outer diameter of the Helicoil.
- Break off the tang: Once the Helicoil is fully inserted, use a tang break-off tool to snap off the tang at the end of the Helicoil.
- Install the screw or bolt: Screw the screw or bolt into the Helicoil to engage the new threads.
People Also Ask About How to Install a Helicoil
What size hole do I need to drill for a Helicoil?
The size of the hole you need to drill depends on the size of the Helicoil you are using. The hole should be slightly larger than the inner diameter of the Helicoil.
What is the difference between a Helicoil and a thread insert?
Helicoils and thread inserts are both used to repair damaged or stripped threads. However, Helicoils are typically made of a spring-like wire coil, while thread inserts are usually solid inserts that are threaded on the inside.
Can I install a Helicoil myself?
Yes, it is possible to install a Helicoil yourself if you have the necessary tools and skills. However, it is important to follow the instructions carefully and ensure that the hole is properly tapped and cleaned before installing the Helicoil.
