marker pen driven over an 8x4 sheet help.

[blackburn mark]

that sounds like a lot of work just to get markings for you to follow with a jigsaw..... it "MIGHT" be only a little bit more heart ache and pain to build a lightweight router to do the cutting for you that will at the very least be as acuraite as following lines with a saw... (a cnc router is really only a plotter with a bit of backbone)

if your only ever going to cut woods with a max thickness of say 2" it needent be a heavy monster of a machine and mounting it verticaly should still be an option.

plenty of people build usable cnc machines with less experience than it sounds like you have.... with a lots patience and the guys on this forum you should be able to get there

ps: we were or are all novices at building cnc's so dont be thinking your going to get a roasting for asking daft questions

Can i make this happen on a shoestring?

that really depends an what "you" mean by "shoesting"
http://www.ebay.co.uk/itm/CNC-Kit-3-...item2a14d75139

£180 driver steppers and power supply.... it wont be fast but it should get you there

http://www.ebay.co.uk/itm/3-linear-r...item3a53ea7f05

this is a tipical kit from linearmotionbearings2008 on ebay.... there are other options but lots of us have splashed a little exta cash and bought from this guy (you need to do some research to find a price for the sizes that you are after) however, considering that you where happy to follow lines with a jigsaw you may be able to find a much cheaper option for screws and rails that would match your jigsaw skills for acuracy :)

now you need to have a look at frame options.... aluminium extrusion, easy to use and a bit pricy.... steel box section needs welding

do you have access to a lath and welder ?

do a bit of research and get some drawings up so we can pull them apart and you should soon start getting a feel for how much blood sweat time and cash its going to take

[Jonathan]

if your only ever going to cut woods with a max thickness of say 2" it needent be a heavy monster

Unless you try cutting it in one pass

If you're only using it for plotting them a timing belt drive (instead of ballscrew) would be fine since the force on the pen is very small compared to cutting. With the stepper kit that Mark just linked to and belt drive it could still be fairly fast as the distance moved per revolution for a belt drive is high ... so the motors don't need to move at a high rpm to get a good feedrate. You just sacrifice resolution which isn't a big issue for a plotter.
I wouldn't advise those motor or that driver for an actual router though - you'll only get fed up with how slow it is and want to upgrade.

I was going to mount my machine on the ceiling originally (so at a funny angle) as that would take up less space and the swarf will just fall away and clear more easily.

now you need to have a look at frame options.... aluminium extrusion, easy to use and a bit pricey.... steel box section needs welding

Doesn't have to be welded, but that's the easiest option. A frame made from wood should be fine for a plotter. Can get away with one of the cheaper bearing options.