Sharpening your drill bits is a practical skill that, once learned, can save you time and money. Rather than discarding worn out bits, you can restore their cutting edges in a few simple steps. This guide will walk you through the process of sharpening a standard twist drill bit.
Why Sharpen Drill Bits?
Drill bits dull over time due to repeated use. This can result in decreased efficiency, poorer hole quality, and can even damage your drill. Sharpening your drill bits not only improves their performance but also extends their lifespan, saving you the cost of purchasing new ones.
What You'll Need
Before you start, you'll need the following tools:
- A bench grinder or a drill bit sharpener
- Safety goggles
- A small container of water
- A pair of pliers (optional)
Before you begin, remember to put on safety goggles. Small fragments can fly off the drill bit during the sharpening process, and it's important to protect your eyes. Also, make sure to use pliers to hold the drill bit if it becomes too hot to handle.
Understanding Drill Bit Anatomy
Before you start sharpening your drill bit, it’s important to understand its basic anatomy. A drill bit has two cutting edges that meet at the tip to form a point. The angle at which these edges meet is known as the point angle. Standard twist drill bits typically have a point angle of 118 degrees.
Step 1: Positioning the Drill Bit
Turn on the grinder and hold the drill bit so the cutting edge is parallel to the front of the wheel. The bit should be at an angle of about 59 degrees to the wheel. Align the edge of the drill bit so that it's in line with the wheel.
Step 2: Sharpening the Cutting Edge
Maintaining the 59-degree angle, turn the drill bit so the cutting edge is against the wheel. Use light pressure to push the bit against the wheel. The aim is to grind a new edge while maintaining the same point angle (118 degrees). Grind until you see a shiny, new surface along the cutting edge.
Step 3: Cooling the Drill Bit
After you've ground each cutting edge, dip the drill bit into your container of water to cool it down. This is important because excessive heat can weaken the bit.
Step 4: Sharpening the Second Cutting Edge
Repeat the same process for the second cutting edge. Try to grind an equal amount on both sides to maintain a balanced bit.
Step 5: Checking the Point Angle
After you've sharpened both cutting edges, look at the bit from the top. The point angle should be roughly 118 degrees. If one side looks longer than the other, regrind the longer side to match.
Step 6: Checking the Cutting Edges
Finally, inspect the cutting edges. They should be sharp, even, and free of any burrs. If necessary, lightly touch up any areas that need it.
Advanced Tip: Sharpening the Relief Angle
For more advanced sharpening, you may want to grind a relief angle behind each cutting edge. This angle allows the cutting edge to engage the material more efficiently. To do this, hold the bit so the cutting edge is still against the wheel, but tilt the base slightly upwards. Grind a small amount to create a relief angle.
Learning how to sharpen drill bits can seem daunting at first, but with a bit of practice, you can keep your bits cutting like new. Remember, it is far more cost-effective to regularly maintain your drill bits than to replace them outright. With these steps, you can ensure your drill bits are always ready for the job at hand. Practice will make perfect, and soon you'll be sharpening your drill bits like a pro!