It-Tech Goliat

Hope this is not too late, but yep, I have been running one for about 18 months now. I have the model with the 580mm stroke Y, and X 830mm (with 80mm useable on the Z when I added in a simple end-stop switch). I have the 3Nm motor option. I made my own control electronics based on fluidnc and external drivers. You will need to add end stop switches to each axis and use a controller that can auto-square Y for best performance.

If you are going to put a router on it, then any of the motor options are likely to be fine. I put a 2.2kW water cooled spindle on mine (the spindle was from IT-Tech too). The folks at IT-Tech were great and made sure that 80mm mount brackets were fitted that suit the spindle. With the 2kW spindle, the Z-stepper supplied was a shade underpowered and I would lose Z-steps occasionally, but I put a larger stepper on the X, and used the 3Nm old X-stepper on the Z, and it ran a treat. I run mine with 7m/s rapid moves with the upgraded X and Z motors and acceleration of 200mm/s^2 and have no trouble with lost steps.

The design uses 20mm linear rails and 1605 ball-screws. The layout of the linear rails means that each of the axes is very compact, and overall it makes for a nice compact machine. The only downside I found was that for the X-axis, as the two linear rails are arranged 'face-to-face', the slide blocks are physically quite close to each other and there is a limit to the rigidity of the X gantry. That is, in the middle of the span, if I ram the Z hard into material, there is a small flex and twist in the X, which means the Z accuracy drops a little. The flex is way way less than you see in most other CNC router structures though, but it is there, and I suspect that in the version with the longer X gantry, it would be more noticable still. The way the linear rails are mounted for the Y and Z does not cause any flex problems and they are really rigid.

Knowing that there can be potential for a small flex in X (rise in Z) means that some toolpaths need a little more planning, but I have had no problems living with it. For example, the worst-case scenario I found was using a 1 1/2" flat bottom bit for skimming epoxy resin that was filled with slate powder off a V-carve inlay. If I tried to be conservative and just take say 0.1mm off the entire wood surface, then the bit may ride up over the top of some of the less-proud epoxy regions, rather than skimming them off (it mills the highspots fine). The bit then rubs and gets hotter, causing the epoxy to soften, and becoming a mess. Taking a full 1mm skim off the entire wood surface works fine though, but that needs to be allowed for when doing the initial V-carve etc. If I did need to do just a very fine skim, then I would use a 6mm upcut spiral which is much sharper than the flat surfacing bit, it just takes a bit longer, but I had no problems with cutting thin slices.

I have milled wood, plastic and *lots* of aluminium on it. I have also milled 3mm mild steel plate, but that is really messy, but the machine has done it. Basically, I have used the machine to mill all the aluminium parts for my new bigger machine