hello viewers 4di wires here with on tutorial video for everyone in the specular vide here I'll be doing a demonstration how to clean the commentator of an armature for a motor don't forget to check out my website at www.keytime.com spray the contact cleaner on the commutator then agitate the surface with the toothbrush this will remove any oils dust dirt or any other contaminants which can cause connection issues and prevent any contaminants from traveling when we clean up the copper surface in the next step also give the rest of the armature washed down with contact cleaner to remove any unwanted dirt or debris only use an electronic contact cleaner otherwise you do risk damaging the insulation within the armature be sure you're also working in a well-ventilated area wearing safety glasses and rubber gloves as you can see the armature has cleaned up some next we will be resurfacing the commutator removing any pitting marks left from arcing embedded dirt etc normally this is done on a lathe but unfortunately not everyone has access to something like this so there will be two alternative options I will be showing use only aluminum oxide sandpaper 600 grit rip off a piece roughly about the width of the commutator holding the armature in one hand wrap the sandpaper around the commutator light pressure turn the commutator and a full rotational motion and not just back and forth also sanding the path of travel and not against it this will give a fairly consistent level surface we do not want to create an uneven surface as this can cause issues now it's better more reliable method using a drill not all armature shafts are the same size therefore you may have an issue using a drill as some trucks do not open a large enough amount I do have a couple of drills I did pick the one with the larger truck have a piece of sandpaper which is the right width and also long and to pinch a couple inches away from the commutator this will allow for a fairly uniform sanding similar to using a lathe ensure the surface imperfections are removed any deep damage can be too much for sandpaper therefore you'll need someone to recut the surface on a lathe after that give the commutator a final cleanup with contact cleaner also clean up in between each of the bars using a plastic scriber to remove any build-up of debris from before or after the resurfacing next is checking the mica depth between each of the bars for this armature it isn't needed but in some scenarios the mica between the bars can be too high preventing the brushes from properly riding on the commutator the mica should be around one millimeter lower than the bars this is also known as mica undercut to cut the mica back there's specific tools for this procedure such as a cutting blade file but a razor knife can also be used after you're done you should be left with something such as this be sure to stay up to date with my latest videos subscribe to my YouTube channel by clicking on the button below the video this concludes the rest of my video be sure to give it a thumbs up and if you have any comments or questions please feel free to post them thanks for watching