Butt/ Straight/ Square Cut
This is the most common and simple joint among all types of piston ring joints.
Angle Cut/ Bevel
The cut is made at an angle to create higher resistance to leakage of the combustion gases.
Step Cut/ Lap Cut/ Overlapping
The cut is made as a step which gives no clear path for the gas or other medium. This joint is more often used on hydraulic applications.
This joint creates a highly effective seal in high pressure engines because the gas pressure behind the piston ring pushes the joint together in operation.
Hook/ Hook Lap/ Hook Seal/ Lock
This piston ring joint allows for easier fitting as it prevents the ring from expanding beyond a certain specified diameter. This joint is used when ring must pass open ports in the cylinder wall.
Angle Step/ Angle Box Lap
This joint is used almost exclusively for hydraulic applications. The gas seal is effective but it is a complex and expensive design.
These type of piston ring joints feature multi-directional seal that provide for superior sealing efficiency. They are designed to pass open ports but these joints are very complex and expensive to produce.
With Side Notch/ With Lateral Stop
This joint has a notch on the top side to accommodate the radial pin in piston groove which prevents the ring from rotating in the groove This is the most commonly used joint for 2-stroke engines where piston rings have to travel over port openings and it is therefore necessary to provide some means of preventing the ring from rotating.
With Internal Notch/ With Inner Stop
This joint has a notch on the inner side to accommodate the pin inside the piston groove which prevents the ring from rotating in the groove.