I've been lurking for awhile, seeing a bunch of different designs. I've settled on a mix between the free cnc plans and the bearing setup that joe200che uses. Travel looks to be 28"Y 17"X 6.5"Z. Using the 3 axis package from HobbyCNC. Should start on it in the next 2 weeks or so.

Comments?

Thanks,
Dave

gorgeous work on the CAD, or is that the machine?

I designed it in a modeling and animation program called Lightwave. Been using it for 14 years now, and although CAD type design isn't it's strong suit (I used it mostly for film and television animation), I'm pretty comfortable with it.
Instead of the more traditional low cost gas pipe and skate bearings, I've heard others using drawer slides. Would they be strong/stable enough? Seems alot easier to impliment.

Dave

I have drawer slides on the old 'MDF Critter', and they are OK for light [no metal, no MDF cuts more that 0.100] hobby use.. I think I paid less than $45 CDn for all three pairs at the time, not really sure any more...
They seem reasonably tight in the center of thier travel, but close to the edges [any axis] a 5lb or so force will visibly move them..
cuts keytags, balsa model plane parts, plexiglass well enough, PCB fab is 'fair', occasionaly a bit on the sloppy side, but still useable..
I think total cost was around $100 for slides, MDF, and _real_ cheap stepper controller.. the motors came out of old printers..

Very good modeling job.... I have started a new machine, here is a link to pics of what i have built.. I to adapted the jgro plans but made it much larger, you can also see the gantry sitting on my present machine to compare the size.

http://www.lumenlab.com/~joe2000chevy/cnc/

Must purchase access!!!!! Says the link

Must purchase access!!!!! Says the link


ok try it again

OK! looks good. A Linux man! Nice work there....

I like the use of an optical mouse for work holding in the video :)

Graham

As I said when I started this thread, I hoped to begin building in two weeks. That was 5 weeks ago. I promised the wife I'd paint and install flooring in the office before I start the router :( , which brings me to my question. I live in Florida and in about 2 weeks (new build start time) we'll be getting into the beginnings of our hellish humid summer. Seeing as MDF and humidity don't mix, what is my build window before I have to paint/seal it? I'm toying with the idea of 80/20 but really don't want to spend alot on a 1st machine.

Thanks

Dave

If you don't think the cost will be too much, then try cabinet grade plywood.

Seeing as conformat screws wouldn't work on plywood ends, how would you join right angles? Screw into corner blocks?

Dave

Use baltic birch plywood, and good quality "drywall type" wood screws. (NOT drywall screws, though). Predrill and countersink with the correct size drill, and it will go together fine. I get my screws from http://www.mcfeelys.com/ The baltic birch will cost quite a bit more than mdf, but it's lighter and stiffer. But you won't have to buy Confirmat screws, so you might save a little money there.

your right about the humidity and mdf i was builing the cnc jrgo plans and it swelled in
a few places and made the bearing hard to movie I may have to change material or find a better way to mount the bearing.

I'm worried about that as well. I'm in southwest GA, just above Tallahassee. I've got the gantry pianted but not the bed, and at present mine is in the living room(the wife likes it there, noo really), it makes a great conversation piece is my argument.... I can''t put it outside on the porch, not enough cover, and too much weather.....no shop as yet either.....

Still weighing my options. I'll build it in the garage (attached). I'll take some humidity readings out there and decide.

Just get some shellac, and brush it on as soon as you cut the parts. It will dry in a couple minutes, and if you need to do more cutting and drilling, it's easy to just brush on a little more to keep everything sealed up.

I reached the same conclusion. MDF wins out due to workablilty, stability and price. I'll just work to keep it sealed.

Dave