Arm & Cone Design – Gold Series


HDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener - Gage Row | Century Products IncGage Row
Double the number of tungsten carbide inserts that actively cut the gage diameter and assists in maintaining tight tolerances and extending in-gage bit life.


HDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener - Gage Protection Row | Century Products IncGage Row Protection
Provides for longer in-gage bit life.


HDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener - Shirttail | Century Products Inc Shirttail/Leg Protection
Hard Facing along with carbide inserts blanket the shirttail and leg, providing superior wear resistance.


HDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener - Dual Grease Reservoir | Century Products IncDual Grease Reservoir
double the volume of grease for longer bit life.


Keyed Arm
Keyed Arm fits into Patented Pocket which ensures integrity of Arm & Cone Assembly.

Century Arm & Cone Assembly

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.

Design Features

  • Quality Forgings – custom metal composition for superior strength over bar or plate
  • Dual Arm & Cone Compensators – larger grease reservoir for longer 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

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 SizeHDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener | Century Products Inc

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.

Cost Effective Tool HDD Tooling - HDD Hole Openers - HDD Gold Series Hole Opener | Century Products Inc

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.