The Rebore-Zit™ 3/8" with 1/4" Pilot drill bit is the only drill bit designed to enlarge a previously drilled hole while retaining the existing wire in that hole. The bit is fabricated with a custom made, hollow bodied drill bit containing a free spinning, swivel eyelet mounted to its pilot hole center shaft. Just secure your existing wire onto the eyelet and re-drill your hole to a larger size. The bit will not twist the wire. Use the appropriate Rebore-Zit™ bit to accommodate the pre-existing hole (pilot hole) and step-up in Rebore-Zit™ sizes until you obtain your desired final hole size.

Final diameter of the hole - 3/8"
Pilot Diameter (pre-existing hole) - 1/4"