How to sharpen knives for a jointer, planer in a home workshop. And how do you know when it's time to sharpen them?
How to determine that it is time to sharpen planer knives and sharpen them with your own hands quickly and easily - these are two questions that worried me from the moment the planer-thicknessing machine appeared in the workshop.
I solved these questions and the result suits me completely.
First - you can determine what to sharpen by the sound that the machine makes when planing.
When the knives are dull, the sound when planing is louder than usual, it vibrates, rumbling, sonorous.
When the knives are sharp, the sound is similar to a rustling and does not stand out much at the noise level of the machine.
Second - when it became clear that it was time to sharpen the knives, they must first be removed from the machine, not forgetting to completely disconnect the machine from the network before that.
In appearance, you can also notice that the knives need sharpening. In the photo below, it is noticeable that the edge of the knife is slightly knocked down.
For sharpening such knives, I made a small device from an oak bar with a cross section of 45x45. I made it using a circular saw with a disc set at an angle of 45 °. Two triangles are cut in the bar from opposite sides - this is to make it more convenient to hold the bar when sharpening. Also, in one of the planes, two shallow cuts were made for installing the knives.
With this setting, the blades of the knives are obtained in the same plane and you can sharpen two knives at the same time. The sharpening angle is 45 °. To hold the knives, I press them with a pair of self-tapping screws. The tip of the self-tapping screw is slightly worn down.
For sharpening, I use diamond stones of different grain sizes: 400 - 800
Such a block is placed on a flat surface and the knives are sharpened by hand using this device. For more convenience, the sharpening area can be pre-painted with a black alcohol marker. It's better to control the sharpening this way.
These knives were not too dull and took me about 10 minutes to sharpen them.
After the knives are sharpened, you need to remove them from the device and slightly correct the reverse plane of the knife.
And then you need to put the knives back into the machine. Usually, devices are included with the machines for their even installation.
Additionally. When knives or nails are chipped in the blades, I first roughly level the blades with a belt sander. I install the sander with the tape up, the knives are clamped in the device and then I carefully grind both blades of the knives until I remove the traces of chips. Then the knives are straightened by hand with bars. It takes 5-10 minutes more time, and the result is good.
For greater clarity, I suggest watching the video.
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Alexander.
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