At the same time, press on the brush to increase pressure. For cleaning commutator pick a stone about 3/4 the length of the commutator bar and as thick as will neatly fit between the brushing rigs.
Brush Seater, 8 in X 1-1/2 in X 1-1/2 in, Grade Ms For best results, use a stone with a width equal to or greater than the width of the brush. At the same time, press on the brush to increase pressure.