Do-it-yourself lawn mower knife sharpening: how to do it right

The blades of such a convenient device for any owner of a country house as a lawn mower are made of high quality steel. However, their sharpening has to be updated. Of course, you can also mow with a blunt knife. But then cutting the grass will be rough, which will lead to its delamination and spoil the appearance of the lawn. You can sharpen it yourself. Here's how to do it right.

Preparing to sharpen lawn mower knives

Before removing an element that requires sharpening, you should secure yourself and the device itself. If this electrical equipment, then it will be enough to disable it. For a gasoline unit, you must first perform some actions:

• remove the cap from the spark plug;
• prevent leakage - you can turn off the fuel valve or drain the fuel;
• turn the device over to the side of the handle (rarely, but the instructions may indicate another action, then follow it);
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• take care of blocking the rotation shaft - for this, substitute a block under the blade, resting on the ground;
• unscrew the locking elements holding the knife counterclockwise.

If the cutter cannot be released immediately, soften the threaded connection so as not to spoil the edges of the bolt or wrench. This can be done with oil or grease. After that, you need to wait a few hours.

Do-it-yourself blade cleaning and straightening

The first step is to remove stuck-on dirt and hardened plant sap. There is no need to clean so that the surface is shiny. It is enough just to rid the blades of all that is superfluous.

During the operation of the device, hard objects - stones, chips - often fall into the working area, which leads to deformation of the blade. To fix it, you need to use a hammer with a slightly rounded firing pin edges.

The knife is placed on the anvil and with gentle blows they achieve the desired shape. It is necessary to edit from the edges of the bent part, carefully moving towards the center.

Launching descent process

This is the name of the area on the knife blade - the boundary between the base of the working part and the surface of the tip. If the cutter has not been sharpened for a long time, it will chip. By removing the edge of the blade at the same angle over its entire surface, it will be possible to get rid of the defects that have appeared. To do this, you need to take an electric sharpener or a fine file. It is important to remove the metal evenly from both blades. This can be achieved by applying the same effort and roughly counting the number of passes.

The smoother the pull-out of the slopes is, the greater the blade resource will be.

Sharpening

You can perform this manipulation with an emery bar with a grit value of 400-600. In the process, the device should be periodically moistened in soapy water. The sharpening itself is carried out on the grain with a broach of the bar from the center of the treated area to the edge.

To increase the productivity of the process, it is worth using a drill with an adapter. A sharpening device should be fixed on its cartridge - a stone or a circle. After switching on, it is necessary to start with a serrated point. It is convenient if it is possible to fix the drill and move the knife along the edge of the grinding wheel.

Do not apply excessive pressure during processing. Movements should be smooth. It is necessary to avoid overheating and try to keep the sharpening angle in one position.

Straightening edges

After sharpening, the blades require dressing or grinding. If this is not done, then due to the formed small burrs on the thinnest part of the blade, it can wrap up.

This will require sandpaper. You can take a view with a grit index in the range from 600 to 800 grit. The sandpaper should be moisture resistant, since before using it you need to moisten it and roll it into a small cylinder - a centimeter and a half in diameter. It should be slightly pressed against the surface of the thin part and gently stretched, moving from the center to the edges.

If the above manipulations - the removal of the slopes and the subsequent sharpening - were carried out only on one side, then the edging of the edges requires processing and the back surface.

Grinding can be done using an emery machine. For this, the grindstone is replaced with a felt wheel. A uniform layer of GOI paste is applied to it.

After turning on the engine, the sharpened element must be pressed against the felt and moved in any direction. Care must be taken that the point does not turn towards the fibers of the circle.

Do not overheat the blade.

Balancing

Before reinstalling the knife, make sure that the halves are of the same weight. Balancing is generally required for double-sided single and split torches.

To check, the blade is placed on a rod or pin clamped in a vice and aligned horizontally. If it works out and there is no advantage, the balance is correct. In case of deviation, it is required to grind off a small amount of metal from the back of one of the halves.

If, after processing, the cutter was able to fix itself strictly horizontally for at least a few seconds, the excess grinding is stopped. Now everything is ready - you can put the blade back in place and start caring for your lawn.