MTI's raise drill steel is designed to be compatible with individual drilling machine capabilities. Each specific machine determines the combined torsional, compressive/tensile requirement as well as the unit length and wrenching configuration. Other design factors include economic considerations of weight, serviceability and durability.
Some O.D. sizes are manufactured in both integral and two-piece designs and are available in a choice of two material strengths. All have the field proven DI-22 rotary connection.
Starter Subs and Starter Steel are similar to drill steel in design and construction. A close tolerance outer diameter is used as a bearing surface through a bushing to control direction in starting pilot holes.
Stress Modifiers, Cross Over Subs and Saver Subs are available upon request.