A standard element required for the manufacture of a Printed Circuit Board is a drill drawing table, also known as a drill table or a drill drawing legend. The drill table lists the size and number of holes for each drill used on the board. Each drill size can be represented by a symbol, a letter, or the actual hole size. The Drill Table is configured in the Drill Table mode of the Properties panel; the assignment of symbols/letters to hole sizes are performed in this dialog. The drill symbols are always configured in the Drill Symbols dialog and the assignments remain consistent for a PCB.
The Drill Symbols dialog can be accessed in the following ways:
The grid area displays detailed information about the mapping of a symbol to a hole size. It can be customized by clicking on and dragging a column header to change the order of columns and right-clicking on a column header and enabling/disabling the checkbox to show/hide the column.
Click the Grouping button to set which properties are to be used to control the assignment of symbol-to-drill events (holes). Holes are clustered initially by hole size and then assigned separate symbols whenever a grouping option that uniquely identifies them is enabled. For example, the design could include a round pad with a 1mm hole and another square pad with a 1mm hole. If Pad Shape is not enabled in Grouping, they will be assigned the same symbol. But if Pad Shape is enabled in Grouping, they will be assigned separate symbols.
Each hole site can be represented by a symbol, a letter or a string showing the actual hole size. These options control the symbol style and size:
These options control the style of drill symbol and when they should be shown: