What changes were making factory production more efficient in the 1920s?

There were two major changes taking place in the 1920s
that made factory production more efficient.  Both are discussed in detail in the link
below.

The first of these was the assembly line system. 
Henry Ford pioneered the use of assembly lines, which allowed him to make cars much more
efficiently than had previously been possible.  This system was more efficient because
each did just one task over and over as parts were brought to him.  This was much more
efficient than moving from place to place or doing more than one
task.

The idea of the assembly line meshed well with the
other factor, which was "scientific management."  This trend, also known as "Taylorism,"
was one in which experts would analyze workplaces to determine where tasks could be done
more efficiently.  They would break each part of the task down into steps and try to see
if any step could be done better, like by having a tray of parts at a different level or
by having a certain size of shovel be used by someone shoveling coal into a
furnace.

By embracing Taylorism and assembly lines,
factories were able to produce goods much more efficiently as the '20s went
along.