I notice on your design the X rails are the same length of the box seciton. I would leave about 5-10mm clearance at both ends to ensure they lie flat in case the box section is distorted at the ends.
Going by your order;
1) Bear in mind the holes in the SBR rails look like they've been drilled by an ape swinging on a pillar drill - you can sometimes even see the pencil lines which mark where the holes go, so don't expect them to be accurate. Make the frame and gantry then mount the rails to the frame by drilling and tapping one hole at a time until you have them aligned and running smoothly, then drill and tap the rest.
3) I found recently that a local shop is cheaper than getting the pulleys and belts online, plus no long delivery time and additional delivery time to send back the items they got wrong!
6) I reckon try LinuxCNC then mach3 then Planet CNC because clearly if you get on well with LinuxCNC then you've saved a lot of money compared to the other options. If not by all meant buy mach 3. Either way don't expect to learn much if anything about Linux though, since one it's installed it's just like using a program on windows.
Foam is an interesting idea, by all means try it but I don't think it would help that much with resonance. As far as I know the issue is not the 'air resonating through the centre', it's the walls of the steel box section that vibrate. To prevent resonance on the not moving parts you should add mass, or some material with good damping properties which tends to be materials made up of particles which rub against each other to dissipate the energy as heat. Sand covers both criteria, but it sounds like that's not an option.
Mmmm, as Jazz has tried it without success (Thanks for that Jazz) the foam seems to be a no-no. I will have to see how the boat is when the machine is done. Sand can always be added later if I make the boxes "water tight" from the start. I guess if it is too noisy and the sand becomes a must, I can always use the router to make book cases along much of the other side of the boat. That'll give me an excuse to by more books as they are needed for ballast!
You can try it for free. It's very easy to install (just a wizard mouse click install ! ), and once it's installed, it's very intuitive. Linux, is basically the windows desktop, and EMC is an Icon to click on to use it ! no need to learn linux in the slightest :)
I'll look into it further...
As a user maybe you could answer a question for me (Mach 3 users, I have the same question for you)?
One of the jobs I wish to do with this machine is to engrave motorcycle engine cases, the reason I like the idea of the Planet CNC software is that it has a function where you can scan an un-even surface (in this case engine covers are often convex curves) and the software then allows for this in the Z travel so that the engraving (or cutting) depth remains constant over the uneven surface.
Does EMC2 (or Mach3) have a similar function?
not as far as I'm aware (for either).
I've seen the Vectric Aspire trial version can map text onto a 3d surface, but that's a bit pricey.
I'd have thought that was more of a Cam operation than a front end op. ?
I've made and engraved quite a few MotoX bike clutch casings. If it's just an engraving then Jonathans way is the best and easy enough to do. Depending on how curved dictates to how dense you need to probe and time taken, thou it's usually a 5min affair has your only needing the curvature not the whole shape etc and the surface area is small.
Also I have a USBCNC card to try but not got round to it yet has the machine I'd like to try it on isn't finished. Will let you know when I do but it won't be for awhile.
I was wondering if using a tool and the case was possible, thanks for confirming that for me.
Still much reasearch to go software wise!
Glad to hear someone else has done this, what software did you use? Software is yet another area that needs much reading, this CNC lark certainly keeps you busy, even without a machine!
Look forward to reading the posts on the USBCNC, will be good to know how it relates to Mach 3/EMC2, which do you use/prefer?