For drilling in metal, a dull drill just plain won’t drill. I start with the drill held against the wheel, so that the cutting edge is horizontal and againstthe bench grinder wheel. The important thing is that the cutting edge ends up the most forward part of the drill,
that the point stays centerd, and that it’s symmetrical.
Then, place the tip of the drill bit near the grinding wheel. Notice the glint of light on the cutting edge between the two flutes. In theory, hold the bit with the shank angled off to the left at about 59 degrees. A drill bit has two cutting surfaces, one on each side of its center axis, that are cut at an angle of approximately 60 degrees.
This plane creates the cutting edge as well as a relief area behind that edge. Carefully lower the separating disk to lightly touch the targeted surface.
Sharpening drill bits by hand— by which I mean a bench grinder. This also got way longer than I expected.
Sharpening drill bits
How to Sharpen a Masonry Drill Bit – How To Sharpen Manually Masonry Bit Youtube
Maintaining the cutting surfaces on your tools will ensure clean, consistent work at the bench. The cutting area and the angle of the relief area plane. To ensure that you grind your drill bit to the proper angle, you can use a jig. Make sure that the drill bit fits snugly in the slot. Wear safety goggles and keep your hands away from the saw blade. Cobalt drill bits have a high resistance to heat, making them perfect for repeated use. Hold the bit at a 60-degree angle and lightly touch the grinder with the sloped side of the conical top. My bits have a 59 degree profile on the cutting edge. If there is too much overhang in the previous step, the red line will approximate the cutting edge at the tip of the bit.
The bit will skate on a metal surface and the hole will be hard to start. After you have created the slot in your wood, check it to make sure that it is large enough to fit your drill bit into.
It is important to grind the drill bit at the right angle and doing it free hand makes this almost impossible. Slide the guide forward so the bit lightly touches the grinding wheel’s surface. Make sure the flute rests on the guide’s tip. Check width of the center cutting edge on the bit. Adjust the overhang and repeat the grinding process if it is not satisfactory. Notice there are no longer any worn, rounded cutting edges casting glints of light. The length and angle of the cutting edge at the tip of the drill bit are good, too. It does not work with smaller bits than 1/8 inch. The angle of the lines in red is 77 degrees. It runs the length of the block and makes a place for the small bits to be cradled. The angle between the red lines is also 59 degrees. This serves as a guide line to align with the leading edge of each half of the bit. Place the block into a vise so the end of the bit rests on top of and against the jaws and so that it just barely extends above the angled surface of the block.
Inspect the bit with a magnifying glass, if necessary. I hear from friends who have used them. The instructions and illustrations for using the tool are printed on the inside of the box lid. Point the front end of the bit at the wheel. Try to keep the peak of the bit centered on the flutes as much as possible. I find the correct angle of my drill bits?2. Check the results you are getting as you go and make minor adjustments.
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