What is the 4 rule on a drill press?

What is the 4 rule on a drill press? - Fix It Cape Town


When it comes to using a drill press, safety should always be the top priority. One important safety measure is understanding and following the “4-inch rule.” This rule dictates that any distance less than 4 inches between the edge of the bit and the edge of the workpiece should not be drilled. In this guide, we will explore why the 4-inch rule is essential for safe and efficient drilling, and provide some valuable tips on how to adhere to this rule effectively.

The Importance of the 4-Inch Rule

1. Preventing Workpiece Instability

Drilling too close to the edge of a workpiece can cause it to become unstable. As the drill bit enters the material, it exerts a considerable force perpendicular to the surface. When this force is applied near the edge, there is a higher chance of the workpiece cracking, breaking, or even flipping over. By maintaining a minimum distance of 4 inches, you can ensure the stability of the workpiece, reducing the risk of accidents.

2. Minimizing Tearout and Fractures

Working too close to the edge can also increase the likelihood of tearout and fractures in the material. When the drill bit exits the workpiece, the material can splinter, resulting in an uneven or damaged surface. This problem is especially common with fragile or delicate materials like wood and plastic. By respecting the 4-inch rule, you give the material enough support and prevent potential damages, resulting in cleaner and more professional-looking drilled holes.

3. Avoiding Contact with Moving Parts

Depending on the design of your drill press, there may be moving parts or accessories that can pose a danger if the bit gets too close. For example, some drill presses feature a rotating table or chuck key that can be hazardous if they come into contact with the drill bit. By following the 4-inch rule, you keep a safe distance between the bit and any potentially dangerous components, reducing the risk of injury.

Tips for Adhering to the 4-Inch Rule

Now that we understand why the 4-inch rule is crucial, let’s explore some practical tips for effectively implementing it in your drilling projects:

  1. Measure and mark your workpiece: Before starting any drilling operation, take the time to carefully measure and mark the desired hole location. This step is essential for positioning the workpiece correctly on the drill press table, ensuring you maintain the required 4-inch distance from the edge.

  2. Use clamps or a vise: Securing your workpiece with clamps or a vise is an excellent way to guarantee stability. This ensures that even if the bit encounters resistance or tries to pull the material, it remains firmly in place. Clamping also helps to prevent any unintended movement or rotation, allowing you to achieve precise and accurate results.

  3. Practice proper drilling technique: When drilling, it’s important to apply consistent and even pressure to the workpiece. Avoid pushing too hard on the drill press or forcing the bit into the material. Let the drill do the work at a moderate speed, and allow the bit to cut through the material smoothly. Maintaining good control and technique reduces the risk of accidents and improves drilling efficiency.

Frequently Asked Questions (FAQs)

Here are some commonly asked questions regarding the 4-inch rule on a drill press:

Q1: Can I disregard the 4-inch rule when using a drill press?

A1: It is strongly recommended to follow the 4-inch rule at all times for safe and efficient drilling. Deviating from this rule can result in accidents, damaged workpieces, and decreased overall productivity.

Q2: Are there any exceptions to the 4-inch rule?

A2: In some cases, with certain workpieces or drill press setups, it may be possible to deviate slightly from the 4-inch rule. However, this should only be done with caution and after considering the potential risks and safety precautions.

Q3: Is the 4-inch rule applicable to all types of drill presses?

A3: Yes, the 4-inch rule applies to all types of drill presses, regardless of size or model. The goal is to maintain a safe distance between the drill bit and the edge of the workpiece, regardless of the specific drill press being used.


The 4-inch rule on a drill press is a fundamental safety measure that ensures the safe and efficient drilling of workpieces. By adhering to this rule, you can prevent workpiece instability, minimize tearout and fractures, and avoid contact with moving parts. Remember to measure and mark your workpiece, use clamps or a vise for stability, and practice proper drilling technique. Always prioritize safety to protect yourself and achieve professional and accurate drilling results.

Handyman Cape Town

Open chat
Contact us now
Scan the code
Hello 👋
Can we help you get a free quote?