Hi, Can someone please tell me about gears changing (low/high) on a PUMA 2500xy. Such as importance in spindle life and spindle speed acceptable for low and high gears. I see that M41-M43 are codes to change gears but when I use these codes in my program it just stops on that line. Are there additional codes required? I've searched the internet about this and can't seem to find an answer. Please post example program.