First tip, don't let the achievement picture fool you... This is for the hammers that squish you down, not the ones that swing like pictured.
Near the start of the 5th USA level you will come across a series of conveyor belts pushing you backwards and 5 squashing hammers. Using your boost or just moving in between run to the 3rd, 4th or last one and then let it hit you.
You should easily get this if not in normal play of the game anyway