Drill Symbols

Now reading version 19.0. For the latest, read: Drill Symbols for version 21

The Drill Symbols dialog
The Drill Symbols dialog


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:

  • From the PCB Properties panel when a Drill Table is selected, click the Drill Symbols button.
  • From the PCB panel in Hole Size Editor mode, right-click in the Unique Holes region then select Configure Drill Symbols.
  • From the Layer Properties dialog, click the Configure Drill Symbols button. The Layer Properties dialog is accessed by editing the Drill Drawing layer in the PCB Printout Properties dialog or from the PCB Printout Settings page of the Smart PDF Wizard.
  • From the Drill Drawing tab of the Gerber Setup dialog, click the Configure Drill Symbols button.


Grid Area

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.​

To sort the drill symbols, click once on a column heading to sort by that column. A small triangle will appear indicating the current sort direction. Click a second time to reverse the sort direction. 


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.

Graphic Symbol

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:

  • Symbol - select to use a symbol at each hole site. The software includes 15 pre-defined symbol styles as shown in the image below. If there are more than 15 hole sizes, alpha characters are automatically assigned.

  • Character - select to use an Alpha character at each hole site.
  • Symbol Size - the height of the symbol/letter displayed on the Drill Drawing layer. Note that this setting applies to all of the symbols/letters used on the drill drawing.

Draw Symbols

These options control the style of drill symbol and when they should be shown:

  • Show Symbols - show a symbol at each hole site.
  • Show Hole Size - show the actual drill size at each hole site as a numerical value.
  • Show Drill Symbols - the default behavior is to not show drill symbols on the Drill Drawing layer. Enable this option to display the drill symbols.
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