... rule, we recommend that the brushes be set at 4 psi pressure. To calculate the pressure, measure ... be quartered. Quartering is setting the brush holders at equal distance around the commutator. For a 4 ... optimum machine performance, the brush must be set at the machine electrical neutral. If the unit is ... size of opening. HITCACHI carbon brush,HITACHI SG-009,carbon brush for power tools,power tools carbon ...