Review on OX Ultimate Wet Core Bit by Ben Chase

First you will need a 1-1/4" F to 5/8" M bit adapter for home use. I'm not sure how the core performs at 18 inches. To get to 18 inches, you'll need to consider an expensive adapter and industrial-grade drill bit or rented core. 4" deep with a 15A angle grinder. It cuts clean cores up to 4" and works great with low speed flow cooling.