I built one.. It was good for my mission. In the end you will have twice the amount of money you first planned into it. That's the truth. Someone will say they built one for $3 grand but they actually have much more than that.
Actually when listening to some one tell about their home built and discuss the low cost and great savings.. believe this.... Open mouth, all lies, except when breathing. For example. One point they always leave out is the computer. You do not want your tweaked computer out in the production area. So you will need another computer.
Cons to a small home built. It is slow. It is time consuming to run. . Slow means waiting long time for work done. Dirt gets every where. Did I mention slow?
If I was planning on doing a lot more router usage I would use this home built model to build a real router. Or better yet, I would save up and buy a real router. (Take this with a box of salt because home built machine designs are rapidly improving.) For example. there is a recent design out using 80/20 extrusions that is amazing. It is strong, accurate, light and fast. The challenge is you must have access to power tools.
Right now a real router will cost just a little more than a home built. But as in almost anything the hardware is not the real cost. The time and learning curve is where it hurts the most. After I spent the money in parts for my little baby a gerber sabre 4x4 went up for sale across town for $5 grand complete.
I spent a lot of time learning about the various drivers, post processors, software and hardware. I spent a lot of time adapting and improvising this and that to make it all work together. It was something I wanted to do anyway. I had a specific mission in mind. When completed It could have cost me more in displaced lost work. But that is another subject.
Do not ignore this fact. CAD software diving a cnc router is nothing like running corel draw and a cutter. Any one who down plays this fact is exaggerating. You could get it cutting parts with in a short time. But, getting it to do professional work will take a long time.
Yes, your software needs will factor as well. The software comes along with great prices. You think Flexi or signlab is high.. Just wait. Or you can go the hobby route and find some adequate lower cost softs around. Look at Mach 3 for example.
When I completed my little home built using hand power tools it several weeks of time and many hours researching online and remaking a few parts.. Suddenly another working XYZ router came up for sale just down the street. It had software and goodies to boot. He wanted it gone and the price was a few thousand more than I had into my small home built. The problem was it was like buying a semi when you have a room for a bike.
Right now there are lots of real nice cnc machines going cheap. If I really wanted to pursue this router deal I would get a loan or save up and wait until I could pounce on a desperation sale.
But remember. The hardware is not the real cost. It is the learning curve. It is the mental ability. It takes a real commitment. And then you have to have a good place to run it. The dust and chip load is unbelievable. It gets every where. This is something you do not want to run in the garage. The wife will let you know first minute how strong your marriage is about the third trip into the house tracking your mess behind you if you try the garage route.
Using an old cutter to convert into a router... the only parts you could use is the motors. Those could be too weak at 50 oz. You will need 300 oz.
Over all.. search out a deal for a "real" router. All the work is done. Just pick it up, set it up and then spend the next year learning how to run the software. You will save your self hundreds of hours and lots of cash in the long run.