The electro-pneumatic pressure control system of a single part lapping station was evaluated to determine operating characteristics and to establish operating procedures and the suitability of control loop components. The effects of variations in upstream pressure, bleed valve opening, lap head clearance, control valve position, and system leaks on steady-state gain and system stability were investigated. Operating methods were established for adjusting machine parameters to linearize steady-state gain over the entire design pressure range. Component changes and additions were recommended for improved system performance. Limits on lap head clearance based on lap head discharge coefficients were established.