Abstract: A bit apparatus in which a cutter member having cutting teeth is axially supported on a shaft for rotation about the shaft, and a bearing mechanism is interposed between the cutter member and the shaft. The bearing mechanism includes at least a radial bearing for bearing a radially directed load and a thrust bearing for bearing an axially directed load. The radial bearing has a shaft-side split bearing member and a cutter-side split bearing member that are opposed to or in sliding contact with each other and capable of rotating relative to each other.

Abstract: A silicon carbide single crystal is produced by allowing a vapor evaporated from a silicon raw material to pass through a heated carbon member and then reach a seed crystal substrate on which a silicon carbide single crystal grows. For this production, an apparatus is used, which has a reaction tube, a heating device and a graphite crucible, wherein the lower part of the crucible constitutes a silicon raw material-charging part; a seed crystal substrate is situated at the top of the crucible; and a carbon member, through which the vapor evaporated from a silicon raw material in capable of passing, is disposed intermediately between the silicon raw material-charging part and the seed crystal. As the carbon member, a porous carbon structure, a carbon plate having a plurality of through holes and a carbon particle-packed layer can be mentioned.

Abstract: Disclosed is a bit apparatus in which a cutter member having cutting teeth is axially supported on a shaft for rotation about the shaft, and a bearing mechanism is interposed between the cutter member and the shaft. The bearing mechanism includes at least a radial bearing for bearing a radially directed load and a thrust bearing for bearing an axially directed load. The radial bearing has a shaft-side split bearing member and a cutter-side split bearing member that are opposed to or in sliding contact with each other and capable of rotating relative to each other.

Abstract: An apparatus for the synthesis of diamond by the vapor-phase process using a combustion flame is provided with a cover set in place in the peripheral region of a combustion burner for enveloping the combustion flame and provided, when necessary, with gas inlets. A method for the synthesis of diamond by the vapor-phase process using the apparatus described above effects the diamond deposition by forming a combustion flame for synthesis of diamond and, at the same time, varying the relative parallel positions of the combustion flame and the substrate.

Abstract: A composite diamond grain which comprises a heat-resistant grain as a nucleus and discrete diamond crystal particles distributed on the surface of the grain or diamond crystal films formed to cover the entire surface of the grain and a method for producing the composite diamond grain by the vapor-phase process are disclosed. For the filament method which is one form of the vapor-phase method, tantalum is useful as the material for the filament. Since tantalum is susceptible of embrittlement by hydrogen, a treatment to be performed on tantalum for the elimination of this drawback is also disclosed.

Abstract: A diamond film of the vapor phase process is produced by a method which comprises a step of (1) electrolytically polishing the surface of a hard metal substrate with a pulse voltage or, after electrolytic polishing, further subjecting it to a scratching treatment with an abrasive powder or (2) electrolytically polishing the surface of a hard metal substrate with a constant voltage and thereafter subjecting it to a scratching treatment with an abrasive powder, thereby heightening the adhesive force of the surface of the substrate, and then effecting deposition of dense diamond of high adhesive strength by the vapor phase process on the substrate.

Abstract: Composite diamond granules using granules of a ceramic substance line SiC as cores and covering the cores with a polycrystalline diamond coating are produced by the vapor phase method. The granules clearly manifest an automorphic diamond face and possess pyramidal projections, square faces, or rectangular faces on their surface. They are highly useful as abrasive granules for grinding. A grindstone obtained by mixing these granules with resin, metal, and vitrified binder and molding the resultant mixture is highly useful.

Abstract: A composite diamond grain which comprises a heat-resistant grain as a nucleus and discrete diamond crystal particles distributed on the surface of the grain or diamond crystal films formed to cover the entire surface of the grain and a method for producing the composite diamond grain by the vapor-phase process are disclosed. For the filament method which is one form of the vapor-phase method, tantalum is useful as the material for the filament. Since tantalum is susceptible of embrittlement by hydrogen, a treatment to be performed on tantalum for the elimination of this drawback is also disclosed.

Abstract: A method for vapor-phase synthesis of diamond comprises burning a raw material compound for synthesis of diamond thereby forming a combustion flame, disposing a substrate for deposition of diamond in said combustion flame, and keeping said substrate at a prescribed temperature, thereby inducing deposition of diamond on said substrate.