A mini grass trimmer of its own design. The device was created from the remnants of cordless power tools and an 18v screwdriver motor.
I recommend the wire brush for the brush cutter: https://s.click.aliexpress.com/e/_AqfL4r

See also my other films:
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   • CIRCULAR Saw Blade on TRIMMER  
   • Brush for cleaning cubes terraces for...  
   • Homemade Chain for TRIMMER EXPERIMENT...  
   • Monofilament disc The trim disc for t...  
   • 6.3 KM Chinese petrol drilling rig fo...