A Different Type of Arms Race

This month’s column is a primer on FlexArm, a product line of articulating cantilever arms from Flex Machine Tools, Wapakoneta, Ohio. The arms assist an operator in performing various manufacturing tasks. The company began manufacturing tapping arms in 1984, and over the years has expanded the product line to include arms for drilling, die and mold grinding, polishing, and for manipulating heavy workpieces — to name a few. The various types of arms are offered in a variety of sizes with different load capacities.

These tools are in the space between a manual tool like a tap wrench or handheld drill and a CNC machine tool or robot. The accompanying image shows a FlexArm tapping arm on the left and a Mag Drill arm on the right. For operators, FlexArm tools ease the burden of carrying the weight of a tool and controlling its torque reaction during an application, allowing them to concentrate on accuracy and productivity with increased safety for both the work and workforce.

These arms have a tool post that attaches perpendicular to a work surface on one end. The tool post is a cylinder with flange or magnetic base; the end of the arm has a hub that fits on the post that allows the arm to rotate around the post. The distance between the tool post and tap center line is manipulated by the operator while the mechanical arm keeps the tap perpendicular to the work surface. With these two degrees of freedom (one rotary and one linear), the tap can be brought to bear anywhere in a workspace.

About Tapping Arms

They have an articulating cantilever suspension that holds the center line of a motor and cutting tool perpendicular to a work surface. The motor may have pneumatic, electric or hydraulic drive. With pneumatics, care must be taken to ensure the air is clean and dry. The air exits through the air motor.

I know from experience that a drop of water on a tap will cause poor surface finish and increased cutting torque. With small taps, this can cause breakage. That being said, for many applications, the pneumatic drive is the right choice. Four sizes of pneumatic tapping arms are available to accommodate tapping capacities ranging from 0 to 7⁄8".