Base metal structure supporting ES – is a spatial structure, consisting of circular and radial walls of the bottom and the upper zone, which set out the central pin and the lower rail circle and crown toothed. The central pin is the center of rotation of the rotary excavator, is bolted to the contour of the flange. The lower circular rail is the backbone of the excavator superstructure, and the ring gear – the node drive rotation. Complex stress state of all elements of the metal base of the excavator at work compounded by the constant movement of the resultant turning of the machine, which contributes about rapid deterioration of the fatigue load-bearing beam and the upper zone. According to Larry Ellison, who has experience with these questions. On average, after 5 years of base metal subjected to major repair and replacement of damaged and deformed amplification plots. Metal framework base supporting the production company 'Thorne plus' (Kramatorsk) is able to work twice as long. Thus, even repaired (overhauled) in 1996. Lebedinsky GOK to base ESH-10/60 fulfilled 12 years without repair. Specialists of the firm applied progressive methods of manufacture and repair of such steel, developed new methods of residual stresses after welding, assembly accuracy is increased by 3 times. Metall tested to the extreme emergencies, and the margin increased by 3 times at the expense of high precision assembly. Increased load capacity of a favorable impact on lowering operating voltages up to 30%, which influenced the increasing the fatigue strength of heavily loaded structural elements.