Micro-electromechanical systems (MEMS) often require tuning to correct for fabrication errors such as changed dimensions or to adapt for a different scenario such as changed temperature. To prevent continuous power consumption for maintaining system behavior, a locking system can be added which does not require any power during operation. A new comb finger locking mechanism design is proposed using an orthogonal spring force on a moving shuttle to generate a locking force in the motion direction through friction. Multiple contact points are placed in line with the spring force to increase the locking force in a volumetric efficient way. The spring is optimized for high locking force but low sensitivity to fabrication errors. Mechanism design is illustrated and successfully tested using a case study example.