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The Digga RC4 Combination Rock/Earth Auger Bit is built for drilling where the ground can change from soil into tougher material. It can handle topsoil, clay, compacted ground, shale, permafrost, and softer fracturable rock, making it a versatile choice for job sites where you may encounter more than one type of ground condition.
The RC4 uses replaceable tungsten-tipped cutting teeth that can dig through earth while providing the extra bite needed for harder material. Available in diameters from 6″ to 36″, it works with compatible auger drives on mini loaders, skid steers, and compact excavators.
What kind of ground is the RC4 made for?
The RC4 is designed for mixed conditions including normal earth, clay, hard-packed soil, shale, permafrost, and softer breakable rock.
How much auger-drive torque do I need?
The amount of torque you need depends on both the RC4 diameter, and what kind of conditions you’re drilling in. In ordinary earth, about 1,450 ft-lb can cover bits through 24″, around 2,250 ft-lb can handle a 30″ bit, and roughly 3,550 ft-lb or more is appropriate for a 36″ bit. In clay, shale, and other harder material, Digga recommends about 2,250 ft-lb beginning with 14″–24″ bits. For 30″ and 36″ RC4 bits in hard ground, the drive should be sized for the specific application. (We can help with that!)
What hydraulic flow and pressure do I need?
The RC4 bit itself does not have a set GPM or PSI requirement. Those requirements come from the auger drive. Digga drives commonly paired with these bits range from about 6–30 GPM, with maximum pressure ratings generally between 3,000 and 3,500 PSI, depending on the drive.
How is the RC4 different from the A4 Earth Auger Bit?
The A4 is primarily an earth auger. The RC4 uses a more aggressive cutting setup that can handle ordinary soil while also working through harder material and fracturable rock.
Should I choose the RC4 if my property has rocky soil?
Yes, especially if you expect a mix of dirt, clay, shale, and breakable rock. If you are drilling primarily into solid or heavy rock, a dedicated rock auger such as the DR6 is the better choice.
Can I use the RC4 in normal dirt?
Yes. The RC4 is designed to work in ordinary earth as well as harder conditions, so you don’t need to switch bits when the ground changes.
Are the teeth included?
Yes. The RC4 includes the appropriate cutting teeth, pilot, and retaining components for the selected size.
Can the cutting teeth be replaced?
Yes. The teeth and pilot are replaceable wear parts.
What auger drive does the RC4 use?
The RC4 uses a 2″ hex connection and is designed for compatible Digga 1MDS through 4DSS auger drives. The correct drive depends on your machine, hydraulic output, ground conditions, and auger diameter.
Can I use an extension?
Yes. The RC4 works with Digga XO20 2″ hex auger extensions.
Does every machine work with every RC4 diameter?
No. Larger augers require more digging power. Your host machine, auger drive, ground conditions, and selected diameter all need to be considered when choosing a setup.
Note: The RC4 Combination Rock/Earth Auger Bit requires a compatible Digga auger drive and machine-specific mount. Exact compatibility depends on machine hydraulics, drive selection, ground conditions, and auger diameter.
Common Compatible Machines
Bobcat Mini Track Loaders: MT100, MT120
Bobcat Skid Steer Loaders: S70, S450, S590, S64-2, S66-2, S650, S76-2, S770, S86-2
Caterpillar Skid Steer Loaders: 226D3, 232D3, 236D3, 242D3, 246D3, 262D3
Ditch Witch Stand-On Skid Steers: SK800, SK900, SK1000, SK1050, SK1750, SK3000
New Holland Skid Steer Loaders: L316, L318, L320, L321, L328
Vermeer Mini Loaders: CTX50, S450TX, S925TX, CTX100, CTX160, ML80, ML100, ML130, ML150
Wacker Neuson Utility Track Loaders: SM60, SM100, SM120
John Deere Compact Excavators: 17 P-Tier, 26 P-Tier, 30 P-Tier, 35 P-Tier, 40 P-Tier
Kubota Compact Excavators: K008-5, U10-5, U17-5, KX018-4, U27-4, KX030-4, KX033-4, U35-4, KX040-5
Takeuchi Compact Excavators: TB210R, TB216, TB20e, TB225, TB230, TB235-2, TB240
Wacker Neuson Compact Excavators: 803, EZ17, EZ26, EZ36, ET40
Digga augers are covered by a 1-year manufacturer warranty against defects in materials or workmanship.
Keep drilling when the ground changes.
The RC4 is built for mixed conditions, so moving from soil into clay, shale, or breakable rock doesn’t necessarily mean stopping to change augers.
Get more versatility from one bit.
If your jobs regularly include both ordinary earth and rocky ground, the RC4 gives you a wider working range than a standard earth auger.
Replace wear parts as needed.
The cutting teeth and pilot are replaceable, helping you maintain digging performance without replacing the complete auger.
Choose the size that fits the job.
Diameters from 6″ to 36″ cover everything from smaller post holes to larger construction and property projects.
At ECHO Eqpt, we actually use and support the equipment we sell. You’re not getting generic answers, you are talking to people who understand how this equipment works in the field. That means faster answers, better recommendations, and no wasted time trying to figure things out on your own.
We’re easy to work with. If something breaks, tell us what actually happened and be honest with us (a good sense of humor doesn’t hurt either). We’re often known to help out even outside of standard warranty terms. And if it’s on us, we’ll own it and make it right. No excuses, no finger pointing - just real support when it matters.
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