Description
Crush through subsurface limestone shelves with the Digga A4-20-3-MFT Auger. This 20-inch heavy-duty bit pins to compact excavator powerheads for caisson and foundation pier work. Multi-facet tungsten teeth fracture caliche and shale ahead of the flighting spiral. The tool bogs down if you force it into pure unweathered blue granite without pre-drilling.
Fabricated around a thick-wall seamless alloy mechanical tube, the central spine resists rotational shock loads from hydraulic planetary drives. Continuous 5/16-inch thick steel flighting delivers dependable resistance against abrasive gravel erosion. Built for compact drive units generating up to 3,500 foot-pounds of torque, the bare tool weighs 122 lbs net. Outer dimensions measure 20 inches in diameter by 48 inches in height, protected with yellow industrial powder coat.
Key Features of Digga A4-20-3-MFT
Commercial foundation contractors buy Digga A4-20-3-MFT bits for solar array footings and light pole piers. Direct commercial auger pricing delivers heavy tungsten tooth engineering that cuts replacement part overhead on demanding rocky jobsites.
- Twenty-inch cutting diameter clears wide footings for commercial foundations and piers
- Four-foot working depth maneuvers well under compact boom reach on trailers
- Multi-facet tungsten carbide teeth shatter hard shale and cemented aggregate
- Continuous steel flighting sweeps broken rock debris out of the borehole
- Cast alloy rock pilot point establishes center holes on sloping rock surfaces
- Two-inch round hub collar fastens onto standard compact equipment drive motors
- Reinforced tooth pockets withstand repeated shock loads from buried boulder strikes
- Balanced spiral pitch clears spoil fast to prevent powerhead stall events
Torque Load Runout Realities
Field rotation tests on an 18-GPM carrier reveal center tube runout below 0.015 inches total indicator reading over four feet. Radial flight deflection measures under 0.034 inches at the tooth edge under 2,400 foot-pounds of torque. Penetrating cemented gravel drops rotation speed from 64 RPM down to 40 RPM, with hydraulic circuit pressure stabilizing near 2,350 PSI. When the teeth strike an embedded six-inch boulder, hydraulic line pressure spikes to 2,950 PSI, requiring the operator to ease boom downpressure to restore rotation.
Field Usability Service Demands
Handling this 122-pound auger requires two crewmen during equipment hookups. The round drive hub fits onto powerhead shafts without sticking when kept clean. Replacing worn tungsten teeth takes under five minutes with a hand hammer and punch. Do not purchase this heavy rock bit for soft topsoil or loose sand where broad dirt teeth drill faster.
- Grease the drive mounting hub socket before sliding it onto the motor
- Inspect tungsten tooth faces each day for chipping after rock excavation
- Clear dry rock dust from tooth pockets before installing replacement hardware
Factory Warranty Manifest Details
Digga covers this unit with a verified 1-Year manufacturer warranty on structural steel tubing and factory welds. The factory shipping pallet holds the complete 20-inch auger body, tungsten teeth with pins, a rock pilot point, and an operator manual. Powerheads and mount linkages require separate purchase.