When sourcing a shoe repair machine, prioritize the stitching speed (typically 500-1000 stitches per minute) and the maximum sewing thickness, which should be at least 10-15mm for heavy-duty leather. Ensure the machine features a 360-degree rotating presser foot for multi-directional sewing, which is essential for reaching tight corners in boots and heels. Additionally, verify the motor type; a brushless servo motor is preferred for B2B buyers as it offers better energy efficiency, lower noise, and precise speed control compared to traditional clutch motors.