Drill Bits 101 Best Bit: Selections For Your Applications

Tri Cone Roller Bits:

These bits have three cones on the end of the bit that rotate as you drill. The advantages of tri cones is that the rotating cones relieve torque and drag while drilling. There are many other types of bits, Tri Cone Roller being the most commonly used. The cones can be sealed or unsealed and have a bearing ball inside to run smoothly. (We recommend the sealed bearing for a longer life out of the bit.)

The cones can be sealed or unsealed and have bearing balls inside to run smooth. (Adtech recommends NOT running unsealed bearings.)

The rollers of these cones are made different for every application. Mill tooth cones, long carbide button, medium carbide button, and short carbide button. Mill tooth cones have jagged end cut in to them and the carbide tungsten (hard surfacing is applied). This bit is used in dirt, clay, and light shale. The cutters on the end can be short to long depending on how technical you want to get. (Riley – Mill Tooth here) Button cones have holes drill in the cone and carbide inserts (buttons) push into them. The button come in short to long. The long buttons are used for light shale –light rock (similar to a mill tooth bit), the medium length ones for medium rock and the short button for hard rock. Some bits have side protection in the form of buttons or hard surfacing applied to the sides (shank) for added protection while rotating. (Riley – Three Button Bits here)

PDC Drilling Bits:

PDC Drilling Bits (Poly-Diamond Crystalline) have no moving parts. The bit is manufactured in one pieces with spiral blades milled into them (or cast). They can be 3 to 8 blades on each bit with holes milled into the blades. Poly Diamond Crystaline wafers are pressed-glued into the holes. As you can imagine, the designs on these bits take many different avenues. This bit is designed to be used in rock. However there are pros and cons with this bit. Some claim they can get make more hole with this dill bit and can be rebuilt if not to damaged. These bit cost more and there is a fine line between damaging the bit beyond repair and repairable. This bit also causes high torque. (Riley – PDC Bit Here)


How to decide the type of bit for your application can become somewhat of a guessing game. Knowing your drilling rig parameters and the formation you are drilling in are two the main factors in making this decision.

What formation will you be drilling?

This is a difficult question, but Adtech has a wealth of information from other drillers that have worked in areas around the USA. Asking the contractor and other drillers in the area might also help. A few drillers have had core samples run before doing the project. The following is a quick run through:

Mill Tooth Tri Cone Bit
Dirt, Clay, and Soft Rock

Carbide Button Tri Cone Bit – Long Tooth
Soft to Medium Rock

Carbide Button Tri Cone Bit – Medium Length Tooth
Medium to Hard Rock

Carbide Button Tri Cone Bit – Short Buttons
Hard and Abrasive Rock

PDC Drill Bits
All Formations (except clay – it will ball up)

Drilling Rig

Your drilling rig, pump, and pipe will dictate the size of bit you should run for your application. Your drill bit should be 1 ½” to 2” larger than the largest ID portion that you are going to be using (not including the size of reamers and stabilizers). The motor should be the largest item and if hard facing or stabilization is on the motor, this will not be counted in the largest point for this application. Review our information on each motor in our Inventory and Recommendation pages.

Oversized Bits

Oversized drilling bits can be used with Adtech Drilling Motors. However your build rate might not be as much as you require or there will be no build at all. Also the bigger the bit, the more torque and drag on the bit. The drilling motor might not put out enough torque to turn the bit and clean up the hole with the amount of fluid provided.

For more information, Contact us and our sales team!

Contact, Email and Call us anytime, 24/7 call answering service will find someone to answer your questions and get you drillin’.

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