Lathes tend to be top heavy, and since raw work is seldom perfectly centered, produce vibration. For these reasons its important for a solid base mounting. Bolting the lathe to the floor or adding extra weight to the base helps.
Going through that "Shopbuilt Machines" Word doc. yesterday I came across David Doman's huge shopbuilt lathe. He got his ideas from two magazine articles, that have caught my attention as well, in the past. David B Doman's site is still active, so I only included the first page of his lathe below. If you would like to see more pictures and the build documentation, here is the link to his site.
So the two designs David refers to in has build have been widely distributed around the net. They were both published in the 80's in "Fine Woodworking" magazine and "Wood" magazine. They have also both appeared in their, post magazine, book publishings as well.
So to begin here is Carlyle Lynch's lathe design, published in Fine Woodworking in March 1986.
And now for something different. If your a welder or have a friend who is a welder and have access to some heavy steel sections, you can build this massive lathe. It might also help if you can turn, or have a friend turn up the massive 2 3/8" spindle. When you look at it, it doesn't look that massive, a credit to it's well designed dimensions. You can turn a 2' diameter hunk of raw hardwood into your hearts desire, with this beast. On the other hand if you want to do metal spinning, as in the small book I recently uploaded, this is just the lathe to do it on. Built by Jerry Blanchard, awesome beast.
As stated in the safety warning, don't take chances with your design, all adjustables should have positive locks, a lock that can vibrate loose, is not a lock at all. Like most machines, there is more than one way to get hurt operating a lathe, if it comes spinning out from between the centers the right way, it only takes once.
So I will upload the "Wood" magazine lathe design named, "Back-To-Basics" shop lathe, hopefully on Sunday, stay tuned. This is the lathe I would have built, if I hadn't found my top of the line (in the 60's) Rockwell/Delta.