So, since I'm new to these forums, I'll begin by introducing myself. My nickname is Schweeb, which is what I like to go by most of the time. I currently draw, program, set up, and run parts in a VM1 Hurco for a small JCI supplier named Alex Products. About the only thing I actually don't do is design the parts. I only have one year of work experience under my belt, but I'm a quick learner.
I am familiar with at least five CAD/CAM programs and proficient in at least two. I have formal schooling in Rhinoceros and Autocad, but I've probably spent the most time in SolidWorks, my personal favorite. My CAM program of choice is Mastercam since that is what I use every day at work.
Despite my profession, I'm actually not very mechanically inclined. I have failed several home projects already due to lack of planning and failed attempts at improvisation. My skills mostly revolve around math and physics; although, I'm capable of quickly learning anything I might need.
With the introduction out of the way, I'll get down to the machine. This mill is designed to be extremely cheap and an introductory course into home built machines. I do not expect to be able to mill steel of any kind, nor do I expect to do much with aluminum other than engraving. My target materials are engraving Lexon or milling plastics.
My current design has a work area of around 30"x36"x14", and it will consist primarily of 1" square tubing welded together. I currently have the rails as 1/2" round stock, but it's well within my budget to go to 3/4". The threads will be 3/8-16 UNC B7 threaded rod. This was virtually my only choice due to cost concerns. I will be using nuts and clamps from DumpsterCNC and Oilite bearings. I have already received my driving kit from Probotix so that's the one component that's not up for changes. I'm using 180 oz in. stepper motors, and I will more than likely using a dremel or a really cheap router with a simple rheostat. The dremel will be thrown in there first to see what I can get away with.
My primary areas of concern are the rails, Oilite bearings, and the size of the machine compared to the motors.
The rails are a huge concern due to their length. The X and Y rails are currently ~4' in length so it might come down to just reducing the size of the machine to relieve the flex in them.
I had never heard of Oilite bearings before stumbling across a thread here. I was struggling in trying to bring the price down when I came across microcarve's design. I honestly have no idea if it's even viable to use them on larger machines. My big question here is what size I could get away with using these things, as linear bearings are quite expensive.
The motors are already bought so they are my absolute largest limiting factor. I honestly doubt they will move such a massive machine which is my primary reason for asking for advice here. Is it possible to drive a machine with over a 2'x2' work area using these tiny motors?
Any comments or concerns are welcome. I have never done anything like this before so it has been quite overwhelming. My biggest fear is that I'll be forced to limit my work area to a 1'x1' area. I'd like as big of a work area as possible.
Eventually, I will build a larger machine, but for now I don't have enough spare money to indulge in this. Most of this is being paid for by my tax return
Some other notes: I'm not interested in buying machine. My total budget is under $1k. I will not use acme threads or ball linear bearings for this machine due to cost. My minimum work area for this to be worth it is 10"x10"x4" with a table around 16"x16".