An employee was doing preventive maintenance on a mold on a work table. One of the pin actuators on the mold was not functioning properly. The employee was using a handheld air hose with a rubber nozzle tip attachment to actuate the pin in and out. The pin would actuate in but not out; while the employee was trying to manually slide the pin, the air hose attachment activated. The pin caught the employee's left middle finger, partially amputating it.