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Home Drilling Equipment Marine Geotechnical Investigation MK 500 Rotary Head



Dando Mk 500 rotary head web

Fitted with a worm and wheel gear totally enclosed  in an oil bath case, the Dando MK 500 incorporates a 150mm I.D. hollow spindle mounted on taper roller bearings.  The head can then be powered by a single piston motor providing controlled rotation and torque in forward or reverse.


With reference to our 24 tonne Rigs, Dando Drilling use a valve with a 140lt slice (i.e.70lt motor) and pressure at 315 bar (4568 PSI). Based on this and with a hydraulic piston motor you will see the following speed and torque:

20:1 Ratio

mk 5000 pistons thb

Maximum RPM 200 @ 3380 Nm (35cc/rev)

Maximum Torque 7725 Nm @ 87 RPM (80cc/rev)

15:1 Ratio

Maximum RPM 266 @ 2534 Nm (35cc/rev)

Maximum Torque 5793 Nm @ 116 RPM (80cc/rev)

12 ½:1 Ratio

Maximum RPM 319 @ 2112 Nm (35cc/rev)

Maximum Torque 4828 Nm @ 139 RPM (80cc/rev)                                                                      

10:1 Ratio

Maximum RPM 400 @ 1690 Nm (35cc/rev)

Maximum Torque 3862 Nm @ 175 RPM (80cc/rev)

Please note- These are the results when fitted to a Dando type circuit and not the actual performance that the Rotary head and hydraulic motors are capable of. The piston motor can run with a pressure of 420 bar (6090PSI) and an RPM of 5000, therefore results will vary depending on your hydraulic capability.

Single Gear Motor Arrangement

The torque advised below is a max because of the pressure limitation of the motor and the speed is based on 140 Lt.
10: 1 Ratio                    

Maximum RPM 190 @ 2305 Nmmk 500 rotary head 22 thb

Maximum Torque 5028 Nm @ 50 RPM

12 ½: 1 Ratio            

Maximum RPM152 @ 2881 Nm

Maximum Torque 6285 Nm @ 40 RPM

20: 1 Ratio                     

Maximum RPM 95 @ 4068 Nm

Maximum Torque 9492 Nm @ 25 RPM

Please note- The 3” Gear motor is limited to 2500psi and is approximately 0.2245 Lt/rev. The motor is capable of 2000 RPM @ 365 Lt/min and performance can vary infinitely depending on the hydraulic supply system.



Estimated Shipping Weight: 438kg

Gear Oil: 8 litres EP Gear Oil Grade 80/90

Hydraulic Oil: Shell Tellus 46 or equivalent

Maximum Pullback: 24 tons.

Estimated Shipping Dimensions: 1m x 0.8m x .7m




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