About this 3D model

I have a CNC machine that I built from http://buildyourcnc.com/book.aspx. Well it was in my basement for a couple years but never really used it because; 1. debris got everywhere, and 2. it was loud! So This weekend I brought it up into the garage where I will keep it (maybe it will get more use.) As right now, it is sitting on the ground, and when I want to mill something, I am going to want to put it outside onto the driveway. But it's heavy!! So I ran to Walmart and found some 2" swivel casters. (I was going to print my own casters but didn't have much time on my side) Now I will be able to roll it out onto the driveway! I knew I had to make something to allow the caster to mount to my CNC stand ends. That is where I came up with this design. I made the holes smaller to be able to tap them. Designed to rest underneath the CNC itself, I added a bolt to secure the mount(1/4-20).