The bit body may be
- Steel Body :
A- The bit body is forged or milled from steel (steel-bodied bits).
B- The cutters on a steel body bit are manufactured as studs.
C- The stud can be set with a fixed backrake and/or siderake (visit the cutter design subject).
D- Field experience with the steel body bit indicates that face erosion is a problem, but this has been overcome to some extent by application of a hardfacing compound.
E- Steel body bits also tend to suffer from broken cutters as a result of limited impact resistance (Figure 20). This limited impact resistance is because there is no support to the stud cutter.
F- They are preferable as they can be easily repaired but suffer from erosion.
- Matrix Body :
A- Matrix Body Bits are constructed in a cast from tungsten carbide (matrix bit).
B- They are more resistant to erosion but are prone to bit balling in soft clay formations due to their low blade height compared with steel bodied bits.
C- Matrix body bits have an economic disadvantage because the raw materials used in their manufacture are more expensive.