General Info
Features & Options
Design
Advantages
Specifications
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CENTURY GOLD SERIES HOLE OPENER
Engineered for HDD Industry
Engineered specifically for the HDD Industry. Century’s Gold Series Hole Openers offer the perfect combination of high penetration rates with the reliability customers have come to expect with every Century Hole Opener.

There is no excuse for unnecessary tripping out of holes or time wasted phishing for Hole Opener parts. Down-time costs money. That is why every Century Hole Opener is engineered specifically to withstand the extreme forces encountered underground.
Performance Driven Design
A Patented Keyed Pocket design ensures the integrity of Arm and Cone Assemblies. This, coupled with a precision machined, solid body design welded to a shaft, results in a superior tool to attack even the toughest bore.

Added to this performance driven design is the ability to rebuild all Hole Openers multiple times. Customer replacement of Arm & Cone Assemblies allows multiple cutting structures to be used in a single body. This turns a disposable piece of equipment into an asset.
Bottom-Line Performance
Your bottom-line performance matters to us. That is why we are always looking to bring tomorrow’s tools to you today.
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Sizes:  24″ – 60″
Cutters:  17″, 22" & 26
Profile:  TCI Conical | TCI Chisel | Milled Tooth
Thread Connections:  5-1/2″ FHDS | 4-1/2″ I.F. (NC-50) | 3-1/2″ I.F. (NC-38)
Rig Size:  200,000 lbs. and up
GOLD SERIES FEATURES & OPTIONS
Standard Options
Active Gage Protection
Shirttail Protection
Advanced hydraulics features
Multiple point stabilization for Balanced Rotation
Built in stabilization features results in a well-balanced tool machined to exacting standards. Interchangeable jet nozzles, job specific front stabilizers and rear stabilizers for increased strength and easy borehole removal are integral components of every custom or off the shelf Hole Opener.

A full line of Tungsten Carbide Inserts (TCI) and Milled Tooth cutting structures are available for a wide variety of formations. Gage Protection features for longer in-gage bit life along with Shirttail/Leg Protection for superior wear resistance are incorporated into both series. The Milled Tooth design uses the most advanced metals to attack the toughest applications.
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Design Features
Precision-machined solid body welded to a Shaft
Patented pocket arm design
Replaceable Arm & Cone Assemblies
Sealed roller journal bearing technology
Largest cross section seal in the industry
Engineered Design Advantages
Provide greater cutting action with larger carbide inserts
Eliminates the need for extra reaming passes with larger cones
Extends the bearing and seal life with reduced cone revolutions
Allows increased load capacities due to larger bearings
ARM & CONE DESIGN – GOLD SERIES
The Arm & Cone Assemblies are an integral component of any Hole Opener. Utilizing our engineering expertise and state of the art 3D modeling system, we have Incorporated key design features into each assembly that extend the life of every Hole Opener.
Drilling Performance
There is a direct correlation between the cone, bearing, seal and carbide insert size to maximizing penetration rates and bit longevity.
Cone Size
Larger cones offer distinct advantages when it comes to drilling. They allow for larger cuts which eliminates passes, larger bearings and seals, and fewer cone revolutions per RPM.

The bottom line effect of these advantages is the time and money saved. Fewer reaming passes combined with fewer cone revolutions as well as the larger bearings and seals allow you to stay on the bottom drilling. The longer you are drilling, the more cost effective your tool becomes.
Bearing Size
Most designs consist of a main roller bearing, ball race, thrust bearing and nose bearing (roller or sleeve). Century’s design utilizes all the bearings to properly distribute the load across the entire cone face. This prevents the point loading and possible premature bearing failure that results from taking smaller cuts versus the larger cuts Hole Openers with larger cones can take. The larger bearings used allow for greater load capacity as well.
Seal Size
Seal size is a critical component in the design of cones. A larger effective seal area provides the advantage of longer seal life. This, in addition to the composition of seal material, is key to designing seals with a better resistance to compression set and abrasive formation wear which extends the running time of Hole Openers that utilize these types of cones.
Larger Carbide Inserts
In looking at the maximum weight on a bit available due to the torsion limits of the drill string and the amount of weight per insert necessary to break rock, it was determined that a very large carbide insert could be used as long as a full cone cutting structure was achieved. These larger inserts can cut rock effectively even though they have the look of a soft formation tool. This offers greater flexibility for boring in areas where the lithology is not well known because the tool can cut both soft and hard formations efficiently without twisting off.
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Design Features
Quality Forgings – custom metal composition offers superior strength
Dual Arm & Cone Compensators – larger grease reservoir for bit longevity
Synthetic Grease – Specially formulated for Century’s sealed roller bearings
High Load, High Energy Cone Configurations
17″, 22″ and 26″
Tungsten Carbide Insert (TCI) and Milled Tooth configurations
TCI Conical, TCI Chisel and Milled
Cost Effective Tool
An integral component of overall drilling performance is the selection of the correct bit. There are many factors that go into the selection of the best bit for any given formation to be encountered. Century’s Arm & Cone Assemblies excel in virtually all soil, cobble and rock conditions.

Our design features take advantage of the four components that have a direct correlation on maximizing penetration rates and bit longevity. When bottom line performance is what you are looking for, Century’s reputation for long bit life is your answer.
ARM & CONE ADVANTAGES – GOLD SERIES
Century’s Replaceable High Load / High Energy Bearing Design comes in both Tungsten Carbide Inserts (TCI) and Milled Tooth configurations. Three different cone sizes are available in our Gold Series, 17″, 22″ and 26″ with three different cutting structures incorporating TCI Conical, TCI Chisel and Milled Tooth profiles.
Century Cone Profiles
Your bottom-line performance matters to us. That is why we are always looking to bring tomorrow’s tools to you today.
C27 Conical
C27 Chisel
Milled Tooth
Arm & Cone Assemblies
17" C27 Conical
22" Milled Tooth
26" C27 Chisel
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HSN O-Ring Seals
For the high energy required, Century has designed and utilizes the largest seal in the industry. HSN Material utilized for wear, heat compression and chemical resistance properties.
Premium Crowned Roller Bearings
Gives the bearing the capability to withstand the extreme high loads.
Premium Floating Thrust Bearing
Allows for reduced frictional heat build-up to ensure lower operational temperatures under high-energy operations. This design facilitates the longer bit life Century’s reputation has been built around.
Gage Row Protection
Double the number of carbide inserts that actively cut the gage diameter and assist in maintaining tight tolerances and extending in-gage bit life.
Shirttail/Leg Protection
Hard Facing along with carbide inserts blanket the shirttail and leg providing superior wear resistance.
GOLD SERIES HOLE OPENERS - SIZES & SPECS
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GOLD SERIES HOLE OPENERS
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