This document is an operator's manual and parts list for the Diamond Products CB744 Concrete Drill, updated in August 2019. It provides comprehensive information on the machine's specifications, safety instructions, operation, and maintenance.
Function Description:
The Diamond Core Drilling Machine, Model CB744, is designed for diamond core drilling in concrete, masonry, stone, and similar materials. It is intended for professional use and must always be mounted on a drilling stand. The machine is equipped with a water feed system, a four-speed mechanical gearbox, a mechanical safety clutch, and electronic features for soft start, overload protection, and thermal (overheating) protection.
Important Technical Specifications:
- Model: CB744 (available in 115V and 230V models)
- Power Input:
- 115V model: 3000W / 26.5A
- 230V model: 3200W / 15A
- Voltage: 115V~60Hz or 230V~60Hz (as per nameplate)
- No Load Speeds (min⁻¹): 385 / 530 / 975 / 1340
- Rated Load Speeds (min⁻¹): 225 / 300 / 565 / 780
- Drilling Capacity: 18" (450mm)
- Dimensions: 21.7" x 6.1" x 8.3"
- Gear Oil Type: 90W SHELL SPIRAX A80/90
- Gear Oil Capacity: 625ml (21.1 oz)
- Spindle Thread: 1-1/4" UNC male, 1/2" BSP female
- Protection Class: Class 1
- Weight: 29.7 Lbs (13.5kg)
Usage Features:
- Water Feed System: Essential for cooling the diamond bit and flushing out abrasive particles. The water feed valve allows adjustment of water flow. A quick-release water coupling is provided for hose connection. Maximum water pressure should not exceed 70 psi (4 bar). Indicator holes on the water feed collar show if seals are worn.
- Gear Selectors: The machine features a four-speed mechanical gearbox to suit different bit sizes and material hardnesses. Speeds are selected using two gear selectors (A, B, C, D). Gear changes should only be made when the machine is at rest.
- Speed 1 (AD): 12"-18" (320-450mm)
- Speed 2 (AC): 7"-12" (180-320mm)
- Speed 3 (BD): 5"-7" (125-180mm)
- Speed 4 (BC): 3/4"-5" (20-125mm)
- Spirit Levels: Equipped with tubular spirit levels for horizontal and vertical alignment, ensuring straight drilling.
- On/Off Switch: A rocker switch controls power. 115V models have a relay-type switch that prevents restarting after power interruption; the switch must be turned off then on again.
- LED Load Warning & Brush Wear Indicator Lamp:
- Flashes red when full load is reached and nearing overload.
- Glows solid red if overload is exceeded.
- Flashes rapidly for 5 seconds when brushes are 80% exhausted, indicating replacement is needed.
- Overload Protection: If overload is sustained for 5-10 seconds, the motor will shut down. The machine must be shut off and restarted.
- Overheat Thermal Protection: Shuts down the motor if its temperature gets too high. The machine should be run at no load for a few minutes to cool down before resuming operation.
- Mechanical Safety Clutch: Protects the operator and machine from excessive torque forces by slipping when the preset maximum torque level is reached (21 Nm recommended).
- Core Bit Mounting: The spindle has 1-1/4" UNC male and 1/2" BSP female threads. Core bits must match the spindle threads and be tightened with two wrenches to at least 200 Nm.
- Diamond Bit Types: Supports wet/dry type-electroplated (surface set) and wet type-sintered (impregnated) diamond core bits. Sintered bits are recommended for this machine and require water.
- Mounting to a Drilling Stand: The motor has a standard four-bolt pattern for attaching a mounting spacer to a drilling stand (not included). The rig can be anchored mechanically, with a vacuum base, or with a jack screw. The stand must be fixed securely before drilling.
Maintenance Features:
- Regular Cleaning: Wipe down the machine with a damp cloth after each use. Avoid solvents on plastic parts.
- Motor Cleaning: Periodically blow low-pressure compressed air through ventilation slots with the motor running to keep it clean. Perform this every 50 hours of operation, or more often in dusty conditions.
- Periodic Maintenance: Check for damaged power supply cables, loose fasteners, and unusual noises/vibration.
- Gearbox Oil: The machine has an oil bath gearbox. The o-ring seal must be replaced whenever the gearbox is opened to prevent leakage. If oil is leaking, the machine must be repaired by a qualified service center immediately. Running without sufficient oil will damage the gearbox.
- Carbon Brush Replacement: The machine is equipped with auto-stop carbon brushes that stop the machine when worn out. The LED indicator lamp flashes when brushes are 80% exhausted. Brushes should be replaced as a pair. Instructions for resetting the brush wear indicator lamp are provided for qualified technicians.
- Clutch Replacement: Detailed instructions are provided for replacing clutch components, including bronze clutch discs, pressure discs, and disc springs. All parts must be pre-lubricated with clean gear oil. The clutch nut should be torqued to 21 Nm (15.5 ft-lb).
- Water Seals: Replace water seals as needed.
- Gear Oil Change: Change gear oil approximately every 100 hours of operation.
- Clutch Discs and Spring: Replace as needed.
- Annual Inspection: Perform a full mechanical inspection, cleaning, and re-lubrication each year.
- Professional Service: All repairs, especially those involving the power supply cord or internal components, must be performed by an authorized service center to avoid safety hazards.
- Disposal: Electric power tools, accessories, and packaging should not be disposed of with household waste but collected separately and recycled in an environmentally friendly manner, in accordance with European Directive 2002/96/EG.
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