Bits ‘n Pieces – The Driller’s Blog

Vulcan 26 mm Core Bit: The Importance of Bridges and Pins

Posted by Rod McCoremick on Jan 11, 2016 10:39:00 AM

The Vulcan 26 mm bit configuration is an awesome option that is great for deep hole drilling. However, we’ve been hearing that some drillers are breaking off the pins under the bridges between the sections, before using the bit. Often this means that the bridges are broken off too.

Don’t do it. The pins and bridges are there for a reason.




The Vulcan is a configuration option that allows you to extend your core bit life. It refers to the height of the crown and currently comes in 16 or 26 mm. The higher the crown the more meters you can achieve before having to change a bit and this is important when you are drilling a deep hole. 

The Vulcan configuration was designed with a bridge technology that reinforces the diamond sections. In the case of the Vulcan 26mm the secret of its success is its water management system. It is constructed with destroyable pins under the bridge that ensure good fluid circulation all the way to the crown.  

These features ensure proper flushing and cooling of the crown and allow you to use every millimeter of the matrix. However, when drilling, the water flow changes when the crown wears down to the mid-section of the crown – the area with the bridges and pins. When you have drilled down to this point of the matrix, there is less space for the water to pass between the sections of the bit so you will see an increase in water pressure. This situation will only last until the crown wears down past the lateral bridge support after which, the vertical pins will blow out and allow full flow to the face of the bit again. Some drillers worried that the reduced water flow, and resulting increase in pressure, would cause the bit to burn or they thought that the matrix needed to be changed. For some busy drillers, the easiest solution was to remove the pins and eliminate the need to deal with a change in water pressure. Our recommendation is to have some patience at this point and continue drilling through the bracing and pins.


The bridges and pins reinforce the sections of the crown. Removing them will weaken the crown, may risk breaking the crown, and reduces the benefit of a higher crown configuration. Yes, it might be mean a little extra attention, but the benefits far outweigh the negatives.

 New Call-to-action

Topics: Basic drilling information, How to choose equipment

We Want to Make Drilling Easier

We know drilling is hard work so our blog is written to help make driller’s lives easier.
This is the place to come for:

  • Topics of interest
  • News on products
  • Everything related to drilling…

Every week you’ll find an article related mineral exploration or geotechnical drilling, with a focus on improving your performance.

Subscribe to Fordia's Blog

Recent Posts

Fordia works with its customers in mineral exploration and the geotechnical and environmental drilling industries, to provide high-quality drilling solutions that increase productivity, lower costs and make life easier for the drilling community.