Date of Defense


First Advisor

Dr. Philip Guichelaar

Second Advisor

Dr. Jerry Hamelink

Third Advisor

Dr. Lowell Wilcox


Manufacturers of cordless screwdrivers use two planetary gear trains in series to reduce speed and multiply torque from a small electric motor. Alternately, a nutating gear drivetrain has the potential to create comparable speed reductions and torque multiplications. To apply nutating gear theory to a cordless screwdriver drivetrain, a study of spur gears, planetary gear reducers, bevel gears, and the theory of nutation was undertaken. Finally, a nutating design was proposed. The advantages of a nutating gear drivetrain over a conventional planetary gear train include: a decreased number of drivetrain parts, an ability to use lower-strength gear materials, a higher overall reliability, and a decreased manufacturing cost. An analysis of bending and surface fatigue stresses showed that nylon gears would have an infinite life.

Access Setting

Honors Thesis-Open Access