In a clutch with two friction discs, an intermediate, or center, plate separates the discs. The plate is machined smooth on both sides because it is clamped between two friction surfaces. An intermediate plate increases the torque capacity of the clutch. It does this by doubling the contact friction area.
Some intermediate plates have drive slots machined in their outer edge. These slots fit over and are driven by hardened steel drive pins press-fit into holes in the flywheel rim. Other intermediate plates have four or more drive lugs that fit to, and are driven by, slots in the clutch cover.
Clutches with heavy-duty intermediate plates may use antirattle springs to reduce wear between the intermediate plate and the drive pins and improve clutch release. Without the springs, the drive slots in the plate would wear excessively, resulting in poor clutch release. Antirattle springs are curved spring steel plates that are wedged between the edge of the intermediate plate and the inside wall of a pot type flywheel. These are spaced equal distances apart (three springs—120 degrees apart; four springs—90 degrees apart).