After communicating back and forth with my school’s shop teachers, I selected the MPCNC design from V1 Engendering. For this machine I decided on a cutting area of 4' x 4' based on the request of the shop teacher. 

By far the most expensive single part of the machine was the 1" stainless steel tubing. The reason for this expense was two-fold. The first consideration was the size of the cutting volume. The second was the machine was going to be in a public-school, where it was bound to take a beating.