When using the Horizontal Milling Conversion, the column should be shortened by 2 inches to allow the headstock to be lowered below the top of the table. The drawings in the linked instructions show the operations necessary for you to accomplish this yourself. Longer attachment screws (included with P/N 6100) are required to reach through the 2" block and into the threaded portion of the upper block. The column and saddle may also be returned to the factory where these modifications will be done for you.