Beyond EDM: When All Else Fails, Helicoil Saves the Day (and Your Part!)

You've tried everything. The bolt is seized, snapped, or simply won't budge. You've hammered, heated, and even brought in the big guns: Electrical Discharge Machining (EDM). But alas, even the precise power of EDM has failed to liberate that stubborn fastener, leaving you with a damaged hole and a project at a standstill. So, what now? When EDM bolt removal doesn't work, don't despair – your best option, and often your only one, is to repair the damaged threads with a Helicoil. And YES, we can perform that task at TAPOUT TEXAS.

The EDM Aftermath: A Tricky Situation

EDM is a fantastic tool for removing broken fasteners, especially those made of hardened materials or in tight spaces where traditional methods fail. It works by using electrical discharges to erode the material of the bolt, essentially vaporizing it away. However, sometimes even EDM can leave you in a bind:

• Residual Material: Despite its precision, EDM can sometimes leave behind microscopic traces of the old fastener, or even slightly alter the surface of the hole, making re-tapping difficult or impossible.

• Enlarged or Irregular Hole: While EDM is precise, a particularly stubborn bolt or an inexperienced operator can sometimes lead to a slightly enlarged or irregularly shaped hole, compromising the integrity of new threads.

• Damaged Parent Material: In some cases, the heat generated by the EDM process, or the initial trauma that broke the bolt, can weaken or micro-fracture the surrounding parent material, making it unsuitable for direct re-tapping.

When you're faced with an un-tappable hole after an EDM attempt, simply trying to re-tap the same size thread is a recipe for disaster. The new threads won't hold, and you'll be back to square one, possibly with an even worse problem.

Enter the Helicoil: Your Thread Repair Hero

This is where the Helicoil thread repair system shines. A Helicoil isn't just a quick fix; it's a permanent, robust solution that restores damaged threads to their original size and strength, often exceeding the strength of the original parent material.

What is a Helicoil?

A Helicoil is a precision-formed coil of diamond-shaped stainless steel wire. When installed, it creates new, strong, and corrosion-resistant threads within a larger, re-drilled hole. The beauty of a Helicoil lies in its ability to distribute the load evenly over the entire length of the coil, preventing stress concentrations and ensuring a durable repair.

Why Helicoil is Your Best Option After EDM Failure:

1. Restores Original Thread Size: Unlike simply drilling and tapping to a larger size, a Helicoil allows you to use a bolt of the original thread size, avoiding the need for special fasteners.

2. Superior Strength: The stainless steel of the Helicoil insert is often stronger than the original parent material, providing enhanced resistance to wear, corrosion, and seizing.

3. Compensates for Imperfections: The Helicoil system is designed to work even with slightly irregular or oversized holes (within specified tolerances), which can be common after a challenging bolt extraction, including EDM.

4. Permanent Repair: Once installed correctly, a Helicoil is a permanent solution, creating threads that are ready for repeated assembly and disassembly.

5. Cost-Effective: Compared to replacing an entire component with damaged threads, a Helicoil repair is significantly more economical and time-efficient.

How to Install a Helicoil: A Step-by-Step Guide

While professional installation is always recommended for critical applications, understanding the process can help you appreciate the effectiveness of a Helicoil repair. Here's a general overview:

Tools You'll Need:

• Helicoil Kit (includes drill bit, tap, and installation tool)

• Tap handle

• Clean rags

• Cutting fluid/lubricant

• Safety glasses

• Air compressor (for cleaning)

The Process:

1. Drill Out the Damaged Threads:

   • Using the specific drill bit provided in the Helicoil kit, carefully drill out the damaged threads. It's crucial to use the correct drill size, as this prepares the hole for the Helicoil tap. Ensure the drill is perpendicular to the surface.

   • After EDM: If the EDM process left any rough edges or irregularities, the Helicoil drill bit will effectively clean and size the hole for the subsequent tapping.

2. Tap the Hole:

   • With the Helicoil tap (also included in the kit), carefully tap new threads into the drilled hole. Use plenty of cutting fluid and apply even, consistent pressure.

   • Turn the tap slowly, backing it out every half-turn or so to clear chips. This step is critical for creating the proper threads for the Helicoil insert.

3. Install the Helicoil Insert:

   • Place the Helicoil insert onto the installation tool. The tang (the small bar at the end of the insert) should be engaged in the slot of the tool.

   • Apply slight downward pressure and turn the installation tool clockwise, winding the insert into the newly tapped hole. The insert should go in smoothly. Stop when the top of the insert is one-quarter to one-half turn below the surface.

4. Remove the Tang:

   • Once the insert is fully seated, use the tang break-off tool (or a punch for larger sizes) to snap off the tang. This tang is only for installation and is not needed for the thread to function.

5. Inspect the New Threads:

   • Visually inspect the newly installed Helicoil. The threads should be clean, consistent, and flush with the surface (or slightly below).

   • Test the new threads with a bolt of the original size to ensure smooth engagement.

Don't Let a Broken Bolt Be the End of the Road

When EDM bolt removal doesn't quite get the job done, and you're left with compromised threads, don't throw in the towel. The Helicoil system provides a reliable, strong, and permanent solution, allowing you to salvage valuable components and get your project back on track. With a little care and the right tools, you can transform a frustrating setback into a successful repair.

For a free quote, email us: info@tapouttexas.com or Call 832-240-6312