Quote Originally Posted by Jonathan View Post
Most of what I said about the machine you linked to in China also applies to the Strike CNC machines, so I wont repeat it here. They've used Hiwin rails on X/Y, which is of course excellent, but the spacing of the bearing blocks on the longest axis is quite small - only the width of the gantry sides. That gets extra travel, but sacrifices so much potential rigidity. The Z-axis supported round rails (I think?) which could be fine, except not how they've mounted them. It's hard to tell from the photo so lets compare to their other machines:

http://www.ebay.co.uk/itm/4-axis-3D-...ht_1071wt_1270

That one uses profile rails which are by far the strongest type of rail, but they've put the bearing blocks on the Z-axis aluminium plate instead of putting the rails on this plate. If the rails are there then distance between the support (bearing block) and the tool tip is proportional to the axis extension, whereas the way they have it this distance is always the maximum value. Increasing this distance clearly decreases rigidity.
When buying from Strike you have to know a bit about what your ordering. Just taking their 'stock' machine might end in disappointment as corners have been cut to meet a price point. Virtually every aspect of the machine is configurable and this is where you have to do your home work and tell them what you want. Of course that means the price goes up too. If you want to flip around the rails and blocks for the Z axis then you have to tell them to build it like that. Same goes for the gantry uprights, ask for larger extrusion to widen the bearing block spacing.