The difference between a metal cased oil seal and a non metal cased one is mainly about how each responds to the machine’s movement. At DEDE SEAL, we often describe it this way: one stays firm because of a metal insert, and the other stays adaptable because of rubber flexibility.
A metal cased oil seal feels more stable once installed. When the shaft warms up or shifts slightly during rotation, the metal insert helps the seal keep its shape. This steady geometry allows the lip to stay in the right position, which is helpful in equipment that runs at varying speeds or carries noticeable load.
A non metal cased oil seal behaves differently. It is softer, easier to seat, and fits well in housings where space is limited. Its flexibility is an advantage in small appliances, light machinery, or situations where installation comfort matters more than structural rigidity.
In everyday use, both types work well when placed in the right environment.
Metal cased seals suit machines that move with force; non metal cased seals suit
machines that move gently. Choosing between them is simply about understanding
how the equipment operates and selecting the seal that feels naturally aligned
with that motion.
