#indexers

According to the reading, it is rare for students to come into indexing courses already having these abilities, and apparently it is also extremely difficult to teach these skills to people who don't already possess them. 

Rotary Index Tables are high precision positioning tools used in special cases of milling and metalworking. Their basic function is to offer the machinist the ability to work based on fixed intervals around a horizontal or vertical axis. By turning a lever connected to a worm-screw that is positioned under the rotary table, users can turn it clockwise or counter-clockwise in full turns. The worm-screw drives some axles that are fixed in intervals under the table, so the table is turned with great accuracy. The ratio between the worm-screw and the axles determines the maximum indexing resolution, and so the applications that each RIT is suitable for. Unique Milling Techniques Rotary index tables can be used for a number of specialized processing techniques and provide solutions in demanding occasions. The most noteworthy utilization of RITs is when combined with a chuck, tailstock and stepper electric motor to work as a light lathe alternative. This use though requires special care and the fast turning of the worm-screw by the motor can accelerate the wear of the table axles. Many also workshops use RITs for the milling of bolt head indented features of various shapes (octagonal, hexagonal etc). Operators calculate the intervals that are needed for the processing of these features and set the table accordingly. Cutting & Drilling Uses Rotary Index Tables are also regularly used for the cutting of straight lines at any angle, arcs and circular shapes. The arcs, being a demanding milling process, can be achieved by adding a compound table so that the center of the table's rotation can be displaced, thus resulting in a progressively off-centric machining. It is often the case that a machinist is called to drill a large diameter hole that the driller can't handle due to its insufficient power. This is another case where indexing tables can help by helping the operator drill multiple smaller holes around the set center of the larger hole. This boring process results in a hole that is equally accurate in terms of dimension and inner finishing as an one-drill hole. Helical machining is another point where rotary index tables can prove their usefulness. Calling for high precision and demanding processing, helixes are not easily materialized using conventional tooling. To create something that takes shape in the three dimensional space, you will need to move the workpiece or the cutting tool along at least three axis (x, y, z). RITs can help on this endeavor by providing the helix stepping through their rotation. This also calls for some pre-calculation and setting depending on the helix mathematical characteristics. Maybe the most common use of the rotary index tables though is the drilling of equidistant holes on a circular flange. Using the tool for this purpose is an easy and straight forward activity that is only requires the calculation of the intervals based on the number of holes and their center to center distance. By re-positioning the flange in off-centric holes, one can further drill each hole into a larger one.