Over time, after numerous brush replacements, wear appears on the armature commutator. This causes the power tool to spark and work less stably. To solve this problem, the collector needs to be machined. This is best done on a lathe, but you can get by with a screwdriver and a vice.
Tools and materials:
- screwdriver or drill;
- wooden slats;
- sandpaper P120 and P600;
- GOI paste and felt;
- a bearing in a mandrel with an internal diameter for the armature shaft;
- vice.
Collector groove
A good bearing of suitable diameter is mounted on the armature shaft from the spline side, if the original one remains in the seat. It is important that it is not broken. The bearing itself is clamped in a vice through a mandrel, this will prevent it from being damaged.
The free end of the shaft from the commutator side is inserted into the screwdriver chuck.
The result is a primitive lathe. This fastening method is applicable when restoring the armature of a screwdriver, drill, hammer drill, jigsaw, or grinder.When grooving the manifold of an angle grinder, you do not need to install a bearing; you can simply clamp its gearbox in a vice.
To sand, you need to attach P120 sandpaper to a flat wooden block. It can be glued or nailed to the side with a stapler. It is important that the width of the rail is equal to or greater than the width of the collector, so that everything is ground in the same plane.
Next, by running the screwdriver in drilling mode and forcing the armature to rotate, you need to apply a grinding block to the commutator along its entire width. To do this, you will need an assistant to hold the screwdriver. In this case, with two free hands it will be possible to grind the collector more evenly, avoiding distortion to one side in the form of a cone. Once the entire width of the collector is shiny, rough sanding should be completed.
The absence of dark areas indicates that there is no groove left in the center.
Next, you need to change the sandpaper P120 to P600 to remove roughness. Fine-grained paper is used without a block. It will not change the geometry of the collector, but will only smooth out the scratches.
To bring the collector to perfection, it needs to be polished using GOI paste and a piece of felt. This will make it very smooth, thereby reducing the wear rate of the new brushes.
This type of machining without a lathe will not remove all the curvature perfectly, but it will restore the manifold to normal operating level. After installing the anchor in place, it will no longer spark like that.
