Rotary Drag Bits Overview

Rotary Drag Bits Overview

Overview

Mills Machine Company has been manufacturing Drag Bits for over 80 years and has established industry standards for Quality and Custom Design. In 1976, we introduced our W6R line of drag bits featuring weld-on field-replaceable blades (this particular style of drag bit is still available as well as the individual weld-on blades). After the W6R line had been out in the field for a while, we soon realized that our customers were starting to experience problems in welding the blades back onto the shanks properly. One of the problems was that the old weld was not being removed from the shank and some blades stuck out further than the others. The other problem was that the proper cutting pitch was not being added, so the bits did not cut efficiently.

In 1990, we introduced our new NW6R line of bits featuring a two-piece design. The first piece is an NW6R connector, made from heat-treated alloy steel with the thread connection of your choice on one end and our special tapered NW6R box thread on the other end. The second piece is the NW6R Bit Head with carbide-inserted blades and our tapered NW6R pin. The NW6R System is versatile and economical. This system offers the option of merely unscrewing the NW6R Head and throwing it away when it is worn out or increasing and/or decreasing the size by screwing on a larger or smaller NW6R Head. You may also change the bit style to a heavy duty design with thicker steel blades and carbide inserts, or change it to a different blade configuration like a Chevron or Apex style for tougher formations.

The NW6R System is economical because it saves you the cost of the alloy heat-treated shank each time a new bit is needed and eliminates the reworking process of a one-piece bit where the blades would have to be torched off and new ones welded on. NW6R Reamers and Stabilizers may be added between the connector and bit head to ream out the hole or stabilize the bit--both of these options are inexpensive alternatives to buying a one-piece design. We also have one-piece forged design drag bits available in step or chevron type with standard pin or box threads. For larger size holes we offer our D6R Drag Bit line featuring heavy-duty bolt-on teeth with carbide inserts. Sizes range from 12 1/4" - 110" in diameter and can be manufactured for regular or reverse circulation. Whether your application is in Water Well, Mining, Construction, or Exploration Drilling, Mills Machine has the custom designed bit to meet your requirements.