Stripped Bolt SOS: Drill It Out Like a Pro!
A stripped bolt, often encountered in automotive repair at locations like a local mechanic's garage, can be a major headache. The right tools, such as a high-quality drill and extractor set from a reputable manufacturer, are crucial for success. Understanding metalworking principles helps in avoiding further damage during removal. This guide provides practical steps on how to drill out a stripped bolt efficiently and safely, turning a frustrating problem into a manageable task.
Image taken from the YouTube channel 4DIYers , from the video titled How to Drill Out a Broken Bolt or Stud .
Stripped Bolt SOS: Drill It Out Like a Pro!
Dealing with a stripped bolt can be incredibly frustrating. Instead of letting it ruin your project, learn how to drill out a stripped bolt safely and effectively. This guide provides a step-by-step approach to help you remove that stubborn fastener.
Identifying the Problem
Before you start drilling, it's crucial to properly diagnose the issue.
- What is a stripped bolt? This refers to a bolt where the head has been damaged, usually from using the wrong size tool, applying too much force, or corrosion. The tool can no longer grip the bolt head, making it impossible to turn.
- Recognizing the signs: Common signs include a rounded bolt head, metal shavings around the head, and the tool slipping when attempting to turn the bolt.
Gathering Your Tools & Supplies
Having the right tools is essential for success and safety. Here’s what you’ll need:
- Safety Glasses: Protecting your eyes is paramount.
- Center Punch & Hammer: Used to create a pilot point for the drill bit.
- Drill Bits: A set of high-speed steel (HSS) drill bits is recommended. Start with a small bit and gradually increase the size. Cobalt drill bits are also a good choice for harder metals.
- Drill: A variable-speed drill is preferable.
- Penetrating Oil: Helps loosen the bolt and makes drilling easier. WD-40 or similar products work well.
- Bolt Extractor Kit: This is a set of specialized tools designed to grip and remove damaged bolts.
- Optional: Left-Handed Drill Bits: These can sometimes grab the bolt and spin it out as you drill.
- Optional: Cutting Oil/Lubricant: Helps to keep the drill bit cool and prevent it from binding.
Step-by-Step Guide: Drilling Out the Stripped Bolt
Follow these steps carefully to safely and effectively remove the stripped bolt.
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Preparation is Key:
- Clean the area around the bolt head.
- Apply penetrating oil and let it soak for at least 15 minutes.
- Put on your safety glasses!
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Creating a Pilot Point:
- Using the center punch and hammer, create a small indentation in the center of the bolt head. This will prevent the drill bit from wandering.
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Drilling the Pilot Hole:
- Select a small drill bit (smaller than the bolt's diameter).
- Start drilling slowly and steadily into the pilot point. Keep the drill perpendicular to the bolt head.
- If using, apply cutting oil to the drill bit to keep it cool.
- Drill straight through the bolt head, penetrating a few millimeters into the bolt's shank.
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Increasing the Drill Bit Size:
- Gradually increase the drill bit size, drilling through the bolt head each time.
- Important: Be cautious not to drill into the surrounding material.
- The goal is to weaken the bolt head without damaging the threads in the hole.
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Using the Bolt Extractor:
- Select the appropriate size bolt extractor from the kit.
- Gently hammer the extractor into the hole you've drilled in the bolt head.
- Attach a wrench to the extractor and slowly turn it counter-clockwise.
- With luck, the extractor will grip the bolt and allow you to unscrew it.
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Alternative: Left-Handed Drill Bit (Optional):
- After drilling a pilot hole, switch to a left-handed drill bit that's slightly larger.
- As you drill, the bit may grab the bolt and back it out.
Dealing with a Stubborn Bolt
Sometimes, the bolt may be incredibly stuck. Here are some additional tips:
- Heat: Applying heat to the surrounding area can help loosen the bolt. Use a heat gun or torch carefully. Caution: Be extremely careful when using heat, especially near flammable materials.
- More Penetrating Oil: Reapply penetrating oil multiple times and allow it to soak.
- Patience: Don't force anything. Take your time and apply steady pressure.
- If the Extractor Breaks: Extractors can break under excessive force. If this happens, you may need to use a different extraction method or consult a professional.
Table: Drill Bit Size Guide (General Recommendation)
| Bolt Diameter (Approximate) | Initial Drill Bit Size | Bolt Extractor Size (Typical) |
|---|---|---|
| 1/4 inch (6mm) | 1/16 inch (1.5mm) | #1 |
| 5/16 inch (8mm) | 5/64 inch (2mm) | #2 |
| 3/8 inch (10mm) | 7/64 inch (2.5mm) | #3 |
| 7/16 inch (11mm) | 1/8 inch (3mm) | #4 |
Note: This table is a general guideline. Always refer to the specific instructions included with your bolt extractor kit.
Preventing Stripped Bolts in the Future
Prevention is always better than cure. Here are some tips to avoid stripping bolts in the first place:
- Use the Correct Size Tool: Ensure the wrench or socket fits snugly on the bolt head.
- Avoid Overtightening: Use a torque wrench to tighten bolts to the specified torque.
- Apply Even Pressure: Keep the tool straight and apply even pressure while tightening or loosening.
- Clean Threads: Clean the bolt and nut threads before assembly.
- Use Anti-Seize Compound: Apply a small amount of anti-seize compound to the threads, especially in areas prone to corrosion.
Video: Stripped Bolt SOS: Drill It Out Like a Pro!
Stripped Bolt SOS: Frequently Asked Questions
Here are some common questions about how to drill out a stripped bolt and get your project back on track.
When is drilling out a stripped bolt the best option?
Drilling out a stripped bolt is usually the best solution when other methods, like using bolt extractors or applying penetrating oil, have failed. If the bolt head is severely damaged and you can't get a grip, drilling is often the quickest and most effective way to remove it.
What type of drill bit should I use to drill out a stripped bolt?
Start with a center punch to create a pilot hole. Then, use a left-handed drill bit. If you don't have one, a standard high-speed steel (HSS) drill bit will work. Select a bit slightly smaller than the bolt's shaft diameter.
How do I prevent damaging the surrounding material when drilling out a stripped bolt?
Use steady pressure and a slow drill speed. Apply cutting oil to lubricate the bit and prevent overheating. Most importantly, drill straight and keep the drill aligned with the bolt's center axis. This prevents the drill from wandering and damaging the threads in the surrounding material.
After drilling out the stripped bolt, what are my options?
After the bolt is drilled out, you can use a screw extractor to try and remove the remaining bolt threads. If that fails, you may need to retap the hole with a tap and die set or use a heli-coil insert to repair the threads.