What is the difference between tubular and cylindrical door locks?

Tubular Door Locks: In a tubular lock, the mechanism for retracting the lock bolt is part of the latch assembly. The outside lock chassis has either a square or half-round extension which passes through this mechanism for actuation. In a tubular lock, the inside and outside spindles are joined by the extension through the latch and move in tandem after assembly.

Tubular Lock Major Components: In a cylindrical lock, the mechanism for retracting the latch bolt is part of the lock chassis. The latch is comparatively simple and connects to the outside lock chassis at the periphery. In a cylindrical lock, the inside and outside knob spindles are independent of each other. Because of the independent spindles and the larger mechanism for retracting the latch, cylindrical locks can be configured for many lock functions, such as storeroom, classroom, etc. In addition, levers can be clutched, i.e., the outside lever rotates without retracting the latch.

Cylindrical locks have larger rosettes and mounting plates. The components are made of thicker steel. They have an inside and outside bushing which requires that the mating spindles are made with more precision to ensure they are round. Cylindrical locks can be configured to more lock functions than tubular locks. These functions, such as storeroom locks, are more often required in commercial settings. Because of the larger, stronger components, especially the latch retraction mechanism, the cylindrical locks hold up to more wear and tear than tubular locks. Because the outside chassis contains the retraction mechanism, which is then covered with a cylindrical protective sleeve, it is easier to achieve a UL fire rating, which is important in commercial applications. Brink's Push Pull Rotate Cylindrical Chassis:

Top assembly Brink's Push Pull Rotate components.