There are a couple of considerations here. While it's true it's harder to cut big pieces with a smaller footprint CNC cutter, you have to consider that almost all the work you will have the opportunity to work with will be to cut parts/objects less than 1 meter square. There is just not a lot of projects out there were they need the accuracy and speed of a CNC cutter to cut out big shapes from full sheets. If you were a production shop and did lots of multipart cut jobs (lots of quantity of smaller parts) working with full sheets from a time perspective does make sense. A good portion of the cut time on a job is loading/unloading and setup. The small shop/ backyard guy seldom is faced with having to do those type jobs (and wring every penny out of each part to make a profit). In fact I would avoid those type of jobs. You will make a lot more money cutting one-off or small quantity jobs and a LOT more if you can offer quick turn on custom cuts or to do personalized decorative cuts. Doing production cutting and working for low wages takes the fun out of the CNC experience!
Usually custom jobs fall into one of two categories: Moderate sized cut pieces of 750mm sqr or less or large jobs of several meters long. Good examples are the decorative cuts for gates and fences that can stretch over 5 meters wide. There it's done in smaller sections and welded to a supporting structure.
There is a market (depending on where you are) for brackets and panels for off-road builders or motorcycle guys. Even then you find a lot of your opportunities are decorative in nature and smaller than 1 meter in size.
You can usually get steel suppliers to cut sheets down. My metal supplier will make one cut for free so I simply have everything cut in half. A 5 X 10 becomes a 5 X 5 ft piece and fits my table. More common sized 4 X 8 sheets become 4 X 4. My need to cut bigger than that over the last 6 years and thousands of cuts can be counted on the fingers of my left hand and leave enough unused to pick my nose (:-).
If you have the room for a big table the incremental expense is not a lot after the gantry weight gets above about 50 KG. Smaller than that allows you to use smaller motors, smaller drivers, smaller power supplies and lower cost electronics.
On the other hand if you never use it the oversize is not of much value.
It's hard to advise when your market is undefined and it's hard to define until you start cutting. I can tell you that I made a lot of money with a table that only cuts a little over 4 ft X 4ft The amount of money you would save in raw material by buying bigger sheets only makes a difference if you can get 100% usage out of the sheet when you put it on the table. It did not take me long to realize I did not want try and compete with production shops and do shift work to make money.
There are some interesting nitch markets that you can explore. It's way better to have a line of products that you can fabricate and make them custom to the buyer. Examples : Decorative firescreens, large wallclocks, personalized outside markers, etc.
You might pop over to our commercial cutting site at
www.FourhilllsDesigns.com. You will find decorative cutting is seasonal but it's profitable.
There are some samples of decorative patterns on our support CD with the MP3000 in CDR (CorelDraw) format. One is an "Old Motorcycle". Cut some out, clean and paint them and hang them up....you will get some interest. Drop me a line and ask me for the Decorative Clock master art. You can use it with CorelDraw to quickly create personalized wall clocks that use a simple $5 quartz movement and large hands and yields a product that sells well for $125.00 USD(18" size).
One last bit of experience: The custom bracket guys (needing a few parts to build their rock-crawler machine) will not see the value in paying you what you will need to get to draw, setup and cut a few pieces. You will get lots of "opportunities" to cut small jobs (especially for Free).
We do not live close to a major city so my cutting business needed to adapt to the market. While we sell all over via the web, most business is local and based on finding nitch things that people will spend money on.
TOM caudle
www.CandCNC.com