Steady, uniform, even, equable, constant are comparable when they mean neither markedly varying nor variable but much the same throughout its course or extent.
Steady is the most widely applicable of these terms; in general it suggests regularity and lack of deviation, especially in movement, but it may imply such fixity in position as to be immovable or unshakable or such consistency in character or conduct as to be perfectly reliable.
When movement, motion, or direction is implied, the term may connote lack of fluctuation or lack of nervousness or a constant uninterrupted flow or pursuit.
Uniform stresses the sameness or alikeness of the elements, parts, units, or instances that comprise a whole (as an aggregate, a series, a combination of instances, a course, or a texture).
Even stresses steadiness more than uniformity; it often connotes a dead level (as in quality or in character) which is unvaryingly maintained or which is incapable of alteration or disturbance.
Equable usually implies some inherent quality which makes for invariability, such as uniformity or freedom from extremes or sudden marked changes or a temperamental calmness.