Which BullseyeBore Core version should I use with standard length bits or longer bits?

The standard versions of BullseyeBore Core (CR1-100 and CG1-100) project a single Reference Pattern and a single Alignment Pattern on the work surface and are designed for an operational drilling range of 2”to 5”. This represents the length of most standard drill bits.

The extended versions of BullseyeBore Core (CR1-101 or CG1-101) introduce a second Alignment Pattern for a total of one Reference Pattern and two Alignment Patterns. The two Alignment Patterns are projected at different diameters on the work surface and are designed for an operational drilling range of 2” to 8”. The Alignment Patterns also provide more flexibility when using specialty drill bits such as spade, aircraft, step, or hex bits.

As a general guide, if you plan to use BullseyeBore Core with standard length drill bits in the range of 2” to 5”, select from the standard versions of BullseyeBore Core (CR1-100 and CG1-100). Conversely, if you intend to use BullseyeBore Core with a wider variety of drill bit lengths in the 2” to 8” range, or you plan to use specialty bits such as Spade, Aircraft, Step, Hex, or Forstner, select from the extended versions of BullseyeBore Core (CR1-101 or CG1-101).