EDM 101 Bolt Removal Guide

Removing a Broken Screw or Bolt Using EDM 101 and a Hex Electrode

Introduction

The EDM 101 uses electrical discharges to erode material. By using a hex-shaped electrode, you can effectively remove a broken screw or bolt while minimizing damage to the surrounding workpiece. The hex electrode will make a perfect shape for a manual tool to be inserted and give you more "bite" into the material, making the removal process faster and more efficient. Depending on how "stuck" the bolt is you may need to go halfway through or all the way, which also reduces the internal stresses and makes the bolt removable.

Step 1: Prepare the EDM Machine and Workpiece

Before starting, ensure the EDM 101 machine is properly set up and the workpiece is secured.

1. Plan the job with a setup sheet Look at the setup sheet we use for all jobs here at TAPOUT TEXAS

2. Turn off the machine and inspect for any mechanical issues.

3. Install the hex-shaped electrode. The size of the hex electrode should match or be slightly smaller than the diameter of the broken screw or bolt.

4. Check the machine’s dielectric tank - dielectric fluid (we use distilled water).

5. Clamp the workpiece securely to the machine's bed or table to prevent any movement during the EDM process.

Step 2: Align the Hex Electrode with the Broken Screw/Bolt

Precise alignment is critical for success.

1. Position the hex electrode directly above the broken screw or bolt. Most EDM machines have optical aids or cameras to help you center the electrode. Use the touch off feature to get your zero.

2. Ensure the electrode is aligned with the central axis of the broken screw or bolt to maintain a clean and accurate erosion process.

3. Ensure the machine is set to the job settings - allowing the electrode to slowly feed toward and through the broken tap during the machining process.

Step 3: Begin the EDM Sparking Process

Once aligned, the machine can begin removing the screw or bolt.

1. Start the EDM machining process by engaging the machine's controls and flushing system (side flush, through flush or both) to initiate sparking between the hex electrode and the broken screw or bolt.

2. The electrical discharges will gradually erode the material from the top down, conforming to the hex shape of the electrode as it progresses.

3. Monitor the process, ensuring that the electrode is advancing steadily and debris is being flushed away properly.

Step 4: Flushing the Debris

As the EDM machine erodes the broken screw or bolt, it produces microscopic debris.

1. Use the dielectric fluid (side flush or through flush) to flush away eroded particles from the gap between the electrode and the broken tap. You can set intervals or use the pre-programed methods to maximize the flush. 

2. The fluid also acts as a coolant, preventing the hex electrode and workpiece from overheating during the process.

Step 5: Inspect and Repeat if Necessary

Once the EDM 101 program has completed:

1. Stop the machine and raise the hex electrode.

2. Inspect the hole to see if the broken screw or bolt has been fully eroded to the depth you selected. You may notice a cavity in the shape of the hex electrode.

3. Using a Hex tool start turning the bolt to remove

4. If any part of the screw or bolt remains, realign the electrode and repeat the process as necessary to full depth or a larger Hex electrode.

5. Clean the hole using compressed air or dielectric fluid to remove any remaining debris.

Step 6: Final Clean-Up and Finishing

Once the broken screw or bolt has been successfully removed:

1. Thoroughly clean the hole with compressed air or dielectric fluid to remove any remaining debris or fluid.

2. Inspect the threads (if applicable) to ensure that they have not been damaged. If necessary, re-tap the hole to restore the threads.

Safety Tips:

• Wear proper protective gear such as safety glasses and gloves when operating the EDM machine.

• Maintain dielectric fluid levels to prevent overheating and ensure efficient flushing of debris.

• Work in a well-ventilated area to avoid the buildup of fumes from dielectric fluid.

• Check the electrode regularly for wear, especially when removing hard materials, and replace, or reface it as needed.

Benefits of Using EDM 101 with a Hex Electrode for Screw/Bolt Removal

1. Precise material removal: EDM allows for accurate erosion of the screw or bolt without damaging the surrounding material.

2. Non-contact process: No physical force is applied to the workpiece, minimizing the risk of additional damage or deformation.

3. Suitable for hard materials: EDM works on materials that would be challenging or impossible to remove manually, such as hardened steel.

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