I often struggle with conventional table or vise-mounted workpiece stops on machining centers, so I use a tool mounted in the machine's spindle as a removable stop that is accurate, versatile and easy to set up. When necessary, I write a part program that positions the machine's dedicated spot drill where I need it, then displays a message and stops the cycle. After the part is loaded against the spot drill and clamped, I press the cycle-start button for the machine to continue.
Other types of tools will work, but I typically use the spot drill because it is always in the machine, its stopping surface (shank) does not vary from wear and tear, and it is often the first tool used in my machining processes. This idea also applies when I need to locate parts from a remote feature, such as a hole or pocket, that would be difficult to reach with a conventional stop. In addition, my idea is safe because there is no chance of forgetting to remove the stop.
Shawn Chaney, Bluffton, Ind.