Contemplating DIY build; quick hi and q's

[EddyCurrent]

Dan, welcome.

I'd like it to remain a tool in the stable for years to come!

I don't know if I'd want people to call me a 'tool'

From what I can gather from basic skim-reading... please tell me true/false where you see fit!

1) Linear *supported* rails are really the only way to go without getting frustrated in the long term.
2) I'm torn between frame. MDF is clearly out, but it's whether to go alu frame or steel? I can weld, I have plenty of tubular steel, but I'm concerned about accuracy of construction. I've seen plenty of commercial offerings and all seem to use alu frame; if I can go that route I'd be more confident in the construction I think, but will I get the accuracy of build I need, or does it make no difference? I understand the pressures the machining will put on the chassis; if I mimic an existing design that uses alu extrusion I presume there's nothing that says I won't be able to machine the bits I'm looking at above?
3) Go proper balls screws, avoid the temptation to use cheap threaded rod, belts, chains

1. From what I've learned, Yes, especially if you want to do aluminium and good accuracy
2. Steel seems the best way, there are methods of construction that allow adjustment in the final stages.
see this thread for example http://www.mycncuk.com/forums/router...on-please.html
3. Ball screws are a must, advice is mostly 1605 for Z and 1610 for X & Y driven by pulley and belt from the motor. Of course it depends on the size of machine you intend.

in terms of controller board I've yet to look into anything. Something USB-based would be good rather than parallel port.

There is an Ethernet device called Smooth Stepper from warp9td.com, I think this is better because I wanted to use USB for other things like a wireless pendant and
didn't want any interaction that might cause the machine to loose steps etc.

Re. PCB's, if it will do aluminium it will do PCB's, I'm using a 2.2Kw spindle but plan to fit 1mm cutters for some jobs, the key seems to be in making a strong/stiff machine that will deliver accuracy at a good speed.

Edit: Forgot you intend Linux first, here's a link to some hardware
http://wiki.linuxcnc.org/cgi-bin/wik...orted_Hardware