First compare air supply and hole diameter range
According to the current Epiroc D50 and D55 product pages, both series use DTH drilling, with listed hammer specifications of 4 inches and 5 inches, as well as a maximum hole depth of 45 m. Their transport dimensions on the current pages are also the same: length 11,350 mm, width 2,500 mm, height 3,500 mm. The current nominal weights differ by only 200 kg: D50 is 22,300 kg, and D55 is 22,500 kg.
Epiroc’s current product pages list a reference hole range of 90–130 mm and engine power of 287 kW for the D50, and 90–152 mm and 328 kW for the D55. Epiroc brochures list an Atlas Copco XRX 10 two-stage compressor for both: the D50 has free air delivery of 295 l/s at 25 bar, and the D55 has 354 l/s at 30 bar. The brochures also list other engine configurations; check each used machine’s configuration and performance against its nameplates, documentation and operating test.
The two used machines in this comparison
GLOBMACH lists stock EB-F51D11F50E as a FlexiROC D50 and EB-B8B5391C71 as a D55. Contact us for the compressor, rotary head, drill pipe, hammer, hours and air supply under load for each machine.
The air-supply figures in the two series brochures correspond to different pressures. Compare EB-B8B5391C71 and EB-F51D11F50E using each machine’s installed compressor configuration, condition and performance under load.
Initial model-series screening by target hole diameter
For applications planned with a hole diameter greater than 130 mm and not exceeding the current D55 series upper limit of 152 mm, the D50 series reference no longer covers the requirement; the D55 series should be examined further. In the range from 90 to 130 mm, the two current series overlap. Within this range, the installed hammer and drill pipe, air supply performance under load, fuel condition, service support and scope of purchase may matter more than the model name.
Do not treat the series parameter boundaries as production guarantees. Rock, altitude, hole depth, flushing requirements and hammer specifications all change the required operating point. The final selection should use the pressure and flow data from the selected hammer manufacturer and follow a load test of the actual machine for the relevant stock ID, performed by qualified personnel under the applicable equipment manual when equipment and site safety conditions permit.
Verify the complete installed drilling system
For each stock ID, record the compressor nameplate, rotary head model, pipe diameter and length, DTH hammer specifications, bit range, drill rod magazine capacity, dust collector and lubrication system. Then itemize which drill rods, DTH hammers, bits and maintenance spare parts are included in the quote. A machine paired with a mismatched set of drilling tools does not constitute a complete package ready to drill.
If one machine has a complete, usable drilling tool assembly while the other needs new hammers, drill pipes or compressor repairs, the choice between D50/D55 changes. Record each included item against the stock ID and the markings in the photos; do not rely on translated listing descriptions.
Load evidence matters more than no-load gauges
A no-load start may reveal obvious alarms or leaks, but it cannot prove the air supply capacity required for drilling. In accordance with the applicable manual, with a qualified operator, and where the equipment and site safety conditions permit, request a steady loaded run and record pressure, temperature and engine performance. Compare the results with the hammer requirements for the buyer's planned altitude and hose arrangement.
Do not diagnose the condition of the compressor's air end from a single video alone. Operating records with dates that correspond to the stock ID, fault-code logs, and a list of leaks or abnormal behavior should be provided for a technician to interpret. This evidence makes EB-F51D11F50E and EB-B8B5391C71 commercially comparable.
Based on the data for the current series, they are almost on par for transport
Because the current D50 and D55 pages show identical transport dimensions and only a small weight difference, transport dimensions alone are not enough of a reason to move from one series to the other. Used equipment still requires measured dimensions and weight, and verification of transport preparation, but the published series comparison redirects buyers' attention to the air supply system and machine condition rather than assumed logistics savings.
Check what each quotation includes. For each option, add the delivered cost of the machine and drilling tools to any costs not included in the quotation for repairing or replacing missing or faulty components, then compare the totals. Quotes depend on the machine’s year, hours, configuration, location and included tools.
Provide operating requirements and machine evidence when requesting a quote
Provide GLOBMACH with the target hole diameter and depth, rock description, hammer preference, site altitude and required daily output. Request the following information for EB-F51D11F50E and EB-B8B5391C71 in the same response table: compressor and rotary head nameplates, drill pipe and hammer lists, load operation records, current faults, evidence of hours, repair history and measured transport data.
Where the target hole diameter falls within the overlapping range of 90-130 mm, choose the used system that can demonstrate the required air supply, has the cleaner operating record, and comes with the more complete drilling tool assembly. If the choice depends on the higher hole-diameter limit of the D55 series, proceed only if the specific D55 machine can substantiate the installed configuration and air supply performance under load behind that choice.
