In a riveting operation, a drift pin is used to align holes in two or more pieces of material before inserting the rivet. The purpose of using a drift pin is primarily for hole alignment.

Here's a breakdown of the purpose:

• Alignment: The drift pin is inserted into misaligned holes to bring them into the correct position. This ensures that the rivet can pass through all the layers of material without obstruction.
• Prevent Damage: Forcing a rivet through misaligned holes can damage the materials or the rivet itself. Using a drift pin minimizes the risk of such damage.
• Facilitate Riveting: By ensuring proper alignment, the drift pin makes the riveting process smoother and more efficient.

More details can be found in various manufacturing and engineering resources. Here is a reliable resource further describing the process: