A little theory
This is the angle of sharpening the drill, it is approximately 120 degrees.
After sharpening, the front cutting part of the tool should be symmetrical. If an offset occurs, it is necessary to correct - regrind.
Behind a cutting edge there is a back cut or a back surface. It should be directed relative to the cutting edge 1 - 1.5 mm down towards the drill shank.
Preparation for surgery
On the grindstone with a marker, draw a line parallel to the axis of rotation. Now we will try to correctly position the drill in the space for sharpening. We attach the drill with the rear cut of the cutting edge to the dash on the grindstone, tightly without gaps. The drill must be placed strictly horizontally!
In this case, the applied feature will be slightly higher than the axis of rotation of the sharpener.
The longitudinal axis of the tool in the horizontal plane will be rotated to the left by about 30 degrees, this will ensure the correct overall sharpening angle of 120 degrees. Remember this position in space.
Let's move on to practice
We take the drill that was in the work, with knocked down cutting edges and try to sharpen it. We find the correct position of the tool in space, we begin sharpening.
First, one side, then the other. We are not in a hurry, we are doing the work as accurately as possible. If the sharpened lump is overheated, it is red hot, we dip the tool into a container of water. Then we continue to work.
Check the result
As if everything worked out. The angle of sharpening is about 120 degrees, the rear cut has the right bevel to the drill shank.
We take a drill, insert the sharpened tool into the chuck. We are trying to drill a steel plate with a thickness of 8 mm.
Everything is going pretty well.
However, the true criterion for a correctly performed operation is a spiral chip. If it is also symmetrical bilateral, then the sharpening angles are optimal.
Short afterword
It is possible that the first time the operation may not work. Nothing wrong. Patience and accuracy, this will give a positive result. A few words about safety. Sharpener must have a protective cover. It is necessary to work with gloves, and strong ones, for example, split ones. Face and eyes should ALWAYS be protected with glasses, and preferably a mask. Successful work for you!
Watch the video
The video demonstrates the process of sharpening the drill manually, so be sure to look.
