Drill press runout demystified: a step-by-step guide to accuracy

Drill press runout refers to the amount of wobble or deviation in the drill bit as it rotates. Excessive runout can lead to inaccurate holes, uneven cuts, and premature tool wear. Checking drill press runout is crucial for ensuring precision and accuracy in your drilling operations. This comprehensive guide will provide you with step-by-step instructions on how to check drill press runout and the tools you need to do it effectively.

Tools Required

• Dial indicator
• Magnetic base
• Drill bit
• Shim stock (optional)

Step-by-Step Instructions

1. Mount the Dial Indicator

Secure the magnetic base to the drill press table, ensuring that it is stable and parallel to the drill bit. Mount the dial indicator on the magnetic base and adjust it so that the plunger tip rests lightly against the drill bit shank.

2. Zero the Dial Indicator

Rotate the drill bit by hand to find the highest point of runout. Set the dial indicator to zero at this point.

3. Rotate the Drill Bit

Start the drill press and let the drill bit rotate at a slow speed. Observe the dial indicator as the drill bit rotates.

4. Measure Runout

The dial indicator will show the amount of runout as the drill bit rotates. Record the maximum deviation in the dial indicator reading.

5. Check at Different Heights (Optional)

To determine if the runout is consistent, repeat steps 1-4 at different heights along the drill bit shank. If the runout varies significantly, it may indicate a bent or damaged drill bit.

6. Use Shim Stock (Optional)

If the runout is excessive, insert a thin shim stock between the magnetic base and the drill press table. This can help reduce runout by adjusting the alignment of the drill bit.

7. Interpret Results

• Acceptable Runout: Runout of 0.005 inches (0.127 mm) or less is generally acceptable for most drilling operations.
• Excessive Runout: Runout exceeding 0.010 inches (0.254 mm) can significantly affect hole accuracy and tool life.

Causes of Drill Press Runout

• Bent or damaged drill bit
• Misaligned drill chuck
• Worn or loose bearings
• Uneven drill press table
• Vibrations from the drill press or surrounding environment

Troubleshooting Excessive Runout

• Replace the drill bit
• Tighten or adjust the drill chuck
• Check and replace worn bearings
• Level the drill press table
• Reduce vibrations by isolating the drill press from the floor or using vibration dampeners

Key Points: Ensuring Precision and Accuracy

By following these steps, you can effectively check drill press runout and ensure the precision and accuracy of your drilling operations. Regular runout checks will help you identify and address potential issues early on, extending the life of your drill bits and improving the quality of your work.

Questions You May Have

1. What is the ideal runout for a drill press?

0.005 inches (0.127 mm) or less is generally acceptable for most drilling operations.

2. Can I use a dial indicator to check runout on other tools?

Yes, you can use a dial indicator to check runout on lathes, milling machines, and other rotating tools.

3. How often should I check drill press runout?

It is recommended to check drill press runout regularly, especially if you notice any signs of excessive vibration or inaccurate drilling.

4. What are the signs of excessive drill press runout?

• Inaccurate holes
• Uneven cuts
• Premature tool wear
• Excessive vibration

5. Can I fix excessive drill press runout myself?

Depending on the cause, you may be able to fix excessive runout by replacing the drill bit, tightening the drill chuck, or leveling the drill press table. However, it is always recommended to consult a qualified technician for more complex issues.