All of our bits are od (outside diameter). The majority of our customers are concerned with the size of the hole they have after drilling. A few of our customers are concerned about the core sample that they pull out. For those customers the general rule of thumb is add 1/4" to the od to get your id (ex: 6 1/4" od bit will give you about a 6" core sample). It's important to understand not all bits are made the same and there can be some variance.
It is impossible to say how many holes you will get out of a bit. There are several factors beyond our control that impact bit performance. They include: A) Speed – If the speed is too high the bit will glaze. If the speed is too low the job will take too long. B) Water – Not too little and not too much. The right amount removes slurry and keeps the cut clean. C) Steel – Slows the cutting process. Maintaining drill motor speed is important. Don't push the bit too hard! Maintain a consistent speed. D) Bond Specs – How the diamonds are bonded to the barrel is important. A soft bond is good for concrete, and a hard bond is good for asphalt. Using the incorrect bond will greatly decrease your bit life. E) Proper Alignment – This means the rig must be properly anchored. A rig can be anchored with concrete anchors, vacuum base or post jack. Standing on the rig is dangerous and not acceptable. F) Operator Experience - An experienced operator knows how to get the most out of a bit!
