As the name suggests, this style of casing shoe differs from the impregnated type in that they are set with a single layer of natural drill diamond in a pre-determined pattern on the working surfaces of the tool. Surface-set diamond casing shoes are recommended for use when drilling relatively soft and abrasive formations such as sandstone or limestone. The diamonds are embedded in a powdered metal matrix body tool crown that is fused to a steel tool body. Unlike impregnated diamond casing shoes where the controlled erosion of the powdered metal tool crown is desirable to expose new diamond crystals, the metal bond matrix used for all Dimatec surface-set diamond casing shoes is extremely tough and wear resistant. The function of the tool crown matrix body on a surface-set casing shoe is to securely hold the diamonds in place throughout the operational life of the tool. Dimatec manufactures surface-set diamond casing shoes that may be used with all sizes of standard casing tubes.

In addition to casing shoes, Dimatec also manufactures surface-set diamond rod shoes. In terms of design, rod shoes are very similar to casing shoes and differ only in their thread connections. Rod shoes are used where wireline drill rods are used as casing tubes.

Tool Configuration

All Dimatec surface-set diamond casing shoes and rod shoes are supplied with a semi-round crown profile and a Regular (Style ‘W’) canal type waterway configuration.

Diamond Quality

Unless otherwise specified, the tool face of all Dimatec surface-set casing shoes and rod shoes are set with economical ‘A’ Grade natural drill diamond. Any of the other standard Dimatec diamond grades may be substituted on request.

In addition, the outside and inside gauge diameter surfaces of all Dimatec surface-set casing shoe and rod shoe crowns are set with a natural mined ‘Kicker’ Grade diamond to assist in maintaining the critical gauge diameters throughout the life of the shoe.

Diamond Size

All Dimatec surface-set casing shoes and rod shoes are supplied with one of three standard diamond size ranges, namely 25, 50 or 75 stones per carat (SPC). The use of diamonds smaller than the 75 SPC range is not recommended for surface-set casing shoes and rod shoes. While it is possible to specify diamonds larger than the 25 SPC range for use on surface-set casing shoes, consideration must be given to kerf width constraints in allowing for sufficient diamond coverage when using larger diamond crystals.

Hard-Stripping of Tool Bodies

Although hard-metal strips that are used to armor coat the steel tool body are normally not provided on Dimatec surface-set diamond casing shoes and rod shoes, this option is available at an additional cost and is recommended when drilling through extremely abrasive and unconsolidated conditions.