My first cnc machine.

[JAZZCNC]

Hi,

Yes the rail design will work fine but Personally I wouldn't use Ali angle has it wears quickly. I would just use Flat bar bolted to the front of Box section. Doing it this way will allow much more adjustment and make it much easier to setup.

Regards R&P then be aware that you probably need a ratio of 2:1 or 3:1 to get decent resolution. Direct drive with no ratio will have large pitch, You'll most likely use Mod 1.5 and even the smallest 12T pinion has quite large pitch, IE: Diametric pitch(DP) x pie so 12T = 18 x 3.141= 56.5mm Pitch.
Now because your not cutting and haven't got to over come cutting forces plus you can build a lighter gantry then you could probably get away with 12T but on the down side your Linear system won't be so efficient so more friction to overcome. So really larger pinion will be better for tooth engagement but this increases pitch, even 56.5mm pitch would be too much for me so I'd want 2:1 on that.
So going lager say to 17T which gives close to 1" DP which is more common pinion size used with R&P and would give 80mm pitch and this would require 3:1 giving nearly 27mm pitch. This is 3 x the pitch you'd have on CNC router and to me would be about right for plasma, thou I haven't much experience with plasma I do have friend who built one with direct drive and know it was no good and ended up have 2:1 ratio applied. This used Mod 1.0 thou which has smaller DP on same tooth pinions to MOD 1.5, thou I seem to remember him saying wished he's used larger Mod but can't remember is reasons.?