What are some things that mechanical engineers know and others don't?

That the father of computers is a mechanical engineer.
Charles Babbage (1791-1871), computer pioneer, designed the first  automatic computing engines. He invented  computers but failed to build  them

He designed something called Difference Engine which is a Mechanical Computer

A mechanical computer is built from mechanical components such as levers and gears, rather than electronic components.

A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. The name derives from the method of divided differences,  a way to interpolate or tabulate functions by using a small set of  polynomial coefficients. Most mathematical functions commonly used by  engineers, scientists and navigators, including logarithmic and trigonometric functions, can be approximated by polynomials, so a difference engine can compute many useful tables of numbers.

Artistic display of a portion of Difference Engine #1

Part of Charles Babbage's difference engine (#1), assembled after his  death by his son, Henry Prevost Babbage (1824–1918), using parts found  in Charles' laboratory

Difference Engine No. 2, built  faithfully to the original drawings, consists of 8,000 parts, weighs  five tons, and measures 11 feet long.The first complete Babbage Engine was completed in London in 2002,  153 years after it was designed

First complete model of difference Engine #2

The London Science Museum's  difference engine, the first one actually built from Babbage's design.  The design has the same precision on all columns, but when calculating  polynomials, the precision on the higher-order columns could be lower.