This paper studies the effect of machining parameters on the performance of worm gears using a special purpose finite element technique. Algorithms are presented to determine the worm and gear geometries by simulating the grinding action of the grinding wheel and cutting action of the hob. Results are presented delineating the effect of machining parameter such as the hob oversize@ hob swivel angle@ profile modification etc.@ on performance parameters such as the contact location and size@ stresses and transmission error of worm gears.