Couple New Guy questions

[Black Mesa]

Being a computer nerd and being interested in machining and metalworking, CNC mills have interested me for quite some time. Ive read the CNC robotics book by Geoff Williams and it has given me some good insight into what goes into making a hobby CNC machine. Im looking to build a small gantry style machine just to little projects I have in my head. I have a couple questions, I didnt see a newbie section but if this is in the wrong place, sorry.

1) Is it possible to cut metals and plastics on a hobby cnc machine? I have a computer case project thats just begging for a CNC machine and most of the stuff I would want to do would be either plastic or metal. Would a router be best suited for this and what sort of cutters would I need?
2) Would the hobbyist kit from stepperworld.com be a good starting point? If I had the schematics Im sure I could build the circuits but $250 for everything doesnt seem bad and it seems it would be a lot more cost effective this way.

Thanks for your help.

[chuckknigh]

Absolutely, a hobby machine can do plastics -- it'll have to be a stiff hobby machine to do metals, but sheet metals like computer cases should prove to be of little difficulty.

Many people start with the stepperworld kit, as well as many of their competitors. One of the favorites is the series called Gecko...by all reports they work great.

-- Chuck Knight

[ger21]

Both the HobbyCNC and the Xylotex *should* give better performance than the Stepperworld board for about the same price.

[Black Mesa]

Im assuming that when you say stiff you mean that the leadscrews dont have much play in them. What could I do to counter the forces caused when machining metal? Is it feasible for a DIYer? Also, what would you recomend for a good beginner program? I know of KCam which doesnt seem bad for $100 but I was just wondering if there is anything better/cheaper.

[ger21]

TurboCNC is cheaper ($60), but runs in DOS. Mach3 is better, but costs more. $159 You can try both for free. www.dakeng.com www.machsupport.com

[randyf1965]

Stiff as in no deflection in the gantry, rails, etc cutting metal involves alot of force (unless taking very light cuts)

[chuckknigh]

I meant stiff, as in no flexibility in the whole machine. Stiff rails, stiff supports, stiff structure, and no backlash (play in the screws) either.

The idea is to keep the router in the position you want...no wandering around. Any flexibility, coupled with the forces involved with cutting metals, will result in a poor quality of cut.

Remember, it's easier to build a stiff router, if it's small. Especially if it's your first attempt.

-- Chuck Knight

[whirlybomber]

EMC/EMC2 is cheaper yet....

here

[Aklz]

I´m a luthier in Brazil and it´s my first atempt to make a cnc to cut wood parts.What should be the best parts (rails,bearings,leadscrews,etc) for a stiffer cnc 24"x35"table area?