The wire gauge or size is fundamental to the setting of any machinery and is controlled by the diameter of the bearing in the wire drawing die.
Naturally wire drawing dies wear as wire is drawn through them due to great frictional resistance.
As the wire drawing die wears then the diameter increases.
Sometimes even if the correct die size is employed the wire can “pull down” and a reduction in diameter is experienced.
A further defect can occur when there is a breakdown in the wire drawing lubricant and particles of the wire embed themselves in the die, causing it to become elliptical or scraped.