This revision removes fabricated penetration-rate, operating-range, field-performance and product-selection claims. It keeps exact annular geometry, nominal declared-load arithmetic, OD surface speed and a connected qualitative core-drill cutaway.
Declared Diamond Core-Drill Geometry Explorer
Enter declared bit OD, core diameter, axial load and rotational speed. The worksheet reports annular crown area, nominal load per plan area, OD surface speed and radial kerf thickness; it does not prescribe drilling settings.
Equation Used
- Core diameter is constrained to remain at least 2 mm smaller than bit OD.
- Bit and core are ideal concentric circles and OD is constant.
- Declared axial load is distributed uniformly over annular plan area only for the reported nominal quotient.
- Rotational speed is constant for the circumference-speed calculation.
- Animation phase rotates crown tracers and moves qualitative fluid tracers only.
- Actual segment contact area, diamond exposure, formation, torque, power, feed stiffness, vibration, runout, friction, wear, cooling, fluid pressure/flow, cuttings transport, hole deviation, penetration rate, core recovery, bit selection, rig capacity, guarding, electrical/water hazards, silica controls and safe operating settings are excluded.
Replaces fabricated performance and operating advice with declared annular geometry and kinematics, and removes unrelated actuator content.
A connected rotary path drives an annular crown
The cutaway connects the motor, gearbox, spindle, hollow rod and annular crown. Rotation cuts an annular kerf while leaving an intact cylindrical core inside the barrel.
Patented portable diamond-drill designs describe a hollow spindle and drill rod supplying water toward the bit. Other core-drill patents document return flow and cuttings outside the rod. The moving tracers identify that topology only; their speed is not calculated.
Geometry does not select a rig, bit or operating point
The worksheet is useful for checking declared circular dimensions and unit conversions. It does not decide whether a tool, bit, support, power source, fluid system or operating condition is suitable for a material or site.
OSHA identifies integrated water delivery as one control for dust during rig-mounted core drilling and requires the system to be operated and maintained according to manufacturer instructions. Follow the applicable exposure-control plan, current tool instructions and site procedures.
Calculate the declared annulus and circumference
Subtract the core circle from the outer bit circle. Dividing declared axial load by this plan area gives only a nominal quotient.
OD is converted from millimetres to metres for surface speed. The radial kerf thickness is half the diameter difference.
A transparent declared-input example
For OD=75.7 mm, core diameter=47.6 mm, F=4500 N and n=400 rpm, crown area is 2721 mm², nominal pressure is 1.654 MPa, OD surface speed is 1.585 m/s and radial kerf thickness is 14.1 mm.
These results are geometry and kinematics only, not recommended drilling settings.
Real drilling requires product and site evidence
Actual loading is not uniform across a simple annular plan area. Segment layout, diamond exposure, formation, feed stiffness, runout, vibration, fluid delivery and wear change local conditions and performance.
The former penetration-rate formula, universal WOB/RPM bands, field results, depth/core-size claims, brand deployments, bit matrix, fluid advice and fault diagnoses are removed because they were not supported for a specific tested system.
Diamond core-drill ledger questions
Does nominal pressure prescribe WOB?
No.
Does surface speed predict penetration rate?
No.
Are the water-tracer speeds calculated?
No.
Does the diagram replace manufacturer instructions or a silica-control plan?
No.
Portable diamond-drill references
- US Patent 2,914,305: portable diamond drill, hollow spindle/rod and water supply.
- US Patent 6,105,692: diamond core, inner water path and outside return.
- OSHA Rig-Mounted Core Saws or Drills: integrated water delivery and silica-control practices.
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