Diamond Drill Bit

HQ Bottom-Discharge Impregnated Diamond Core Bit

The HQ bottom-discharge impregnated diamond core bit is a dedicated coring tool for wireline drilling systems. Its defining feature is the waterway arrangement at the bottom of the bit face: flushing fluid discharges directly across the cutting face rather than being split through inner and outer annuli. This creates efficient cooling and cuttings-evacuation channels at the cutting interface while substantially reducing direct fluid impingement on the core—an advantage in broken, loose, and water-sensitive formations.

The matrix is produced by powder metallurgy, with synthetic diamonds uniformly embedded at a designed concentration. As the matrix wears during drilling, fresh diamonds are continuously exposed, producing a self-sharpening effect that sustains stable penetration rates and long service life in hard to very hard abrasive formations. HQ is a DCDMA standard wireline size with a nominal hole diameter of approximately 96.0 mm and a core diameter of 63.5 mm, widely used in solid mineral exploration, geotechnical investigation, and underground coal-mine coring.

Dimensions & Specifications

Parameter Specification
Model HQ
Hole Diameter 96.0 mm / approx. 96.0 mm
Core Diameter 63.5 mm
Bit Outer Diameter 95.57 mm
Bit Inner Diameter 63.5 mm
Matrix Height 6–15 mm（customizable）
Diamond Mesh Size 25/30–35/40（selected by formation）
Matrix Hardness F0–F18（matched to rock conditions）
Waterway Type Bottom-discharge
Connection Standard DCDMA HQ  / DCDMA HQ wireline

Suitable Formations

  1. Broken and loose sedimentary formations : shale, mudstone, siltstone, and interbedded sand-mud sequences. Bottom-discharge ports prevent flushing fluid from directly striking the core column, improving core recovery and preserving stratigraphic sequence.

  2. Medium-hard to very hard abrasive formations : granite, quartzite, basalt, gneiss, diorite, diabase, etc. The impregnated matrix keeps exposing fresh diamonds in abrasive ground, delivering steady penetration and predictable bit life.

  3. Water-sensitive and collapse-prone formations : the bottom-discharge configuration reduces annular fluid disturbance to the borehole wall; combined with inhibitive fluids, it lowers the risk of hole tightening, block falling, and collapse.

  4. Coal measures and geotechnical coring : roof and floor coring in coal seams, dam and bridge foundation investigation, and tunnel advance coring where undisturbed core is required.

Application note : In extremely soft, highly sticky, or strongly swelling formations, bottom-discharge ports may plug; adjust fluid rheology and pump rate, or switch to an alternative waterway profile.

Product Advantages

  • Bottom-discharge geometry : fluid reaches the bit face directly for full cooling and smooth cuttings removal, with minimal core washout.

  • Adjustable matrix : F0–F18 hardness options matched to formation hardness and abrasiveness, balancing bit life against penetration rate.

  • Controlled diamond specification : high-strength synthetic diamonds with formation-specific mesh size and concentration for consistent exposure.

  • Standard compatibility : DCDMA HQ wireline compliant, fitting mainstream HQ core barrel assemblies.

  • Factory customization : matrix height, waterway count and profile, and diamond parameters adjustable to operating conditions; bulk supply available.