I've been working on a homemade 4th axis for my CNC machine - here's the pictures and a few videos! I'll be making some parts with it soon! :)
Edit: This is my first version of a 4th axis, I am now 3 versions later so please check out the newest stuff HERE and HERE and HERE (wait till the end of the video) :) Thanks!
This first design I decided to go with MDF because it's easier to cut on the CNC machine and I wasn't sure how it was all going to work, turns out the "block" of MDF is pretty solid and it may just work out in the long run - time will tell :)
The first group of pictures and the first video is of the CNC machine cutting out the MDF - I basically made 4 layers and bolted them together into a block... Ignore the brass bushings and threaded rod - that idea was scraped when I worked out how to turn aluminum on the Shopsmith ;) After that I decided to make my own spindle shaft that would fit the bearings perfectly and would also allow me to use all my Shopsmith lathe fixtures (including the new 3 jaw chuck!)
I tapped the end of the custom spindle shaft so I could bolt on the belt gear that I'd salvaged from an old printer (yes I have tons of old printer parts from salvaging the motors for the first CNC machine)
and the links to the videos...