Cement mixer construction comes in different design and build. This is true due to each builder tries to keep the cost to a minimum, one builder suggests his design is better than the other, most of the time, parts availability in the area is one factor to consider, too. Below are photos of different built, different brand, with varying prices that gives me the ideas on how I conceived mine:
Kobalt brand from Lowes Store.
This was built from a discarded washing machine.
Made from a metal drum.
This looks like a big hand mixer to me.
Hand driven swinging metal drum.