GrandPro

Large diameter bits (over 15-1/2”) with premium sealed bearing designed for multiple drilling of upper sections (surface hole drilling), they have increased bit life during forced drilling practices. GrandPro Line may have both friction and roller bearings. The friction bearings have constituent parts made of antifriction wear-resistant material with silver coating to increase bearing life.

Cutting structure

This product line may have either milled teeth or TCI. Cutting structure designed with advanced software systems provides effective drilling of any rock type and prolongs bit life. To increase steel teeth life, a patented material is used that consists of a mixture of spherical cast tungsten carbide and small hard-alloy grains. Depending on the rock hardness, either side surfaces or side and end surfaces of steel teeth are hardfaced. The gauge may be protected with tungsten carbide inserts. For additional protection against gauge loss, a near gauge of tungsten carbide inserts may be used.

The gauge and the near gauge rows may include diamond-coated tungsten carbide inserts. Depending on the application, these inserts may come up to 30%, 50% or 100% of the total amount of inserts.

Lubrication system

Bit lubrication system is designed to compensate grease consumption and pressure during long-term operation. It consists of a grease reservoir with a rigidly mounted cap, a flexible diaphragm, a metal canister protecting the diaphragm from breakage, and channels to connect the grease reservoir with friction areas in bearings.

Shirttail and leg protection

Shirttail and leg leading edge are hardfaced and may be protected with tungsten carbide or diamond inserts or a combination of tungsten carbide and diamond inserts. Bits may have stabilization features.