Here is the result of two years work I practising CNC using the marvellous Rustica Design.
I spent some time testing the construction and the use of it, and I gathered and helped a good group of model makers in my club and surroundings to build theirs!
But, since I like to experiment and design things; I have just finished my creation of an ultrasimple table. (Nevertheless it was extremely inspired by the concept of Rustica)
It is not portable but on the other hand, the mathods used and work necessary to build it are really reduced.

- Since I often cut different wings, (washout, varying chords, etc) and this was part of the reason for the beginning of the CNC foam cutting concept). I found that on Rustica the carriages extended too far and with the great angles, the arc or the wire was fixed against various elements. I thus imagined a system with the essence being under the table carriages, which would work cantilever and is guided by only 3 bearings: 2 are guided in a maintained angle aluminum 15x15 with 45° by small squares fixed at the edge of the table. A third bearing rolls on the backhander to prevent the carriage from rocking.

- Nothing falls into the guide rails (like dust poly or small or large pieces, falls etc. (You can even close the sides completely)
- Guidance is relative to the table and if it's on that plane, the carriages follow it.
- The useful travel of the carriages, in spite of the use of a threaded rod of one meter, is 96 cm instead of 80 cm of Rustica
- There is nothing which goes beyond the table
- This design, rids the need for ends in MDF, considering you no longer need the support of mason and the tube
- The motor of X is fixed under the table by means of a square - same at the end of the threaded rod.
- There are nothing any more but 2 bearings per vertical carriage

- I kept the MDF for the making of the carriages but the parts are simpler and smaller
- the system of the brackets and nuts take-up play and function Cardan joint
is super and I preserved it.
I put together photographs of the construction, the plans in DES (corel
designer10), in bmp and the files plt for the making of the parts in
the layout of the vertical carriages.
 

Material:

4 engines step by step (for example CONRAD ref. 071338-C1 to 6,90? 27,60Euros
3 threaded rods M6 of 1 m (stainless, brass or galvanized quite right) with 0,40? 1,60 Euros
8 nuts M6 0,25 Euros
4 ends of hose (silicone preferably) 10 X 8 or 10 X 8 of surroundings 25 mm -
4 ends of hose (silicone preferably) 8 X 4 of 40 mm (driving couplings) -
12 bearings 22 X 8 X 7 to 1,3 15,60 Euros
4 angles aluminum 15 x15 mm of 1m20 (maximum race) or 1m 8,00 Euros
20 squares 50 X 50 mm with 0,15? 3,00 Euros
2 tubes aluminum or steel diameter 10 mm of 1m 2,25 Euros
4 pieces of epoxy board or similar Ci of +/- 100 X 30 mm -
1 piece of MDF (or another wood) of +/- 18 mm of 10 X 40 cm (carriages) -
1 board (MDF or other) of 1m20 X desired width (table) according to dimensions.
(I use 60 cm they are extra for the planes and sweptback wings and thing like significant angles)
2 vertical reinforcements of the same wood (120 X 10 cm) -
4 screws M5 X 25 milled heads + 12 nuts M5 \
2 screws M5 X 15 milled heads + 4 M5 nuts|
4 screws M8 X 25 + 4 M8 nuts + discs|
12 screws M4 X 25 + nuts|Some? for screws and bolts
8 screws m3 X 25 (fixing engines)|
wood screw 3 X 16/
2 does U aluminum 10 X 10 X 1 m 20 for the arc + 20 cm boil of wood 8 X 20 4,00Euros

- If there is a milling machine or a buddy who has some, one uses the plt files joined to cut out the parts in the zip file of the diagram (preferably coppered 2 faces to avoid the wear of vés by the wire).
If not to bore according to the plan and to cut out in a simpler way of the rectangles in Ci.
- to assemble the parts of the vertical carriage as on the photographs 005 and 006
- To cut out 2 rectangles of 120 X 100 mm and 4 rectangles of 30 X 100 mm in the piece of MDF of 10 X 40 cm
- To drill according to the plan (wicks 10 and 4) (if required to increase all for passage of the hose)
- to drill 4 of the squares to 30 mm of the corner (see plane) (wick of 5) and to shorten them to 3 mm of the edge of the hole
- to drill 2 of the squares to 34 mm of the corner (see plane) (wick of 5) and to shorten them to 3 mm of the edge of the hole
- to screw the square on the carriages according to the plan

- to fix the bearings on the squares by means of the screws M5 at head milled and of the nuts

- one can drill a hole of 3,5 and insert a screw M4 to make an adjustment height of bearing

- to fix the engines

- to assemble the pieces of wood and the tubes aluminum of 10 by means of the screws M4 X25 and to stick them on the horizontal carriages

- to refine the position of the bearings (20 mm of the tubes) by means of the nuts

- to shorten with dimensions squares to 20 mm (attention: my squares 50 x50 make 49 X 51 rather.... thus locate all the squares by marking them on the longest side and shorten the other)

- to stick 6 squares to 45° on each angle of 1 m20 initially wirh superglue then to reinforce with epoxy

- to prepare the table with its vertical reinforcements placed at 10 cm of the edges (see photographs)

- to prepare two fixing angles adapted to the stepper

- to fix the steppers of X, equipped with their threaded rods (connected by the hose) as well as a pierced square with 7 on the same level as the axis of the engine, the axis of the threaded rod must be to 50 mm of the edge of the table

- to prepare two parts of coupling of the carriages of X on the threaded rods (a hole of 4 and one hole of 10 (or 12 following the thickness of the hose) in falls of CTP or others. And to laterally drill a hole of 3,5 in each carriage. To install the carriages on the rails and to couple them with the threaded rods (the longitudinal offsetting and use for taking up slack is ensured by the two M6 nuts enclosed in the hose which passes in the hole of the part of coupling

- the carriages pass completely to the top (below) of the steppers, which makes it possible to have a race of more than 96 cm on the x axis

- position your Spartia as you wish it (at home suspended between two other tables) connect your steppers and cut out!

- To cut two lengths of 60 + 1/2 width of table + 30 cm in aluminum U of 10 x10
- To cut a V to 60 cm of one of the edges in the side walls and to fold with 85° (a little less than 90)
- to cut out two small squares of 20 x20 and length a 200 mm in a wood end of 8 X 20 mm of section
- to epoxy the small squares to reinforce the angles and the other piece to join both half arcs without them being touched
- to drill two holes of 4 and to insert two screws M4 to make connection with the electric cable of heating.

- two kerfs to make hooks for the hot wire

- you can paint it to look metallized to give an illusion of thick brushed aluminum (some find that wood made bad mechanics of a system HIGH TECH

- You cnc use counterweights in genuine lead to improve the stability of the carriages

- the additional bars anti-cant and their two bearings (one recovers the falls of the angles is what makes it possible to prevent the carriages from rocking towards the interior because of traction of the arc when one cuts out with significant angles and a height max.

- dust protection side closures : two Scotch tape bands 50 mm stuck between the edges of the table and the angles prevent dust from flying in the rails

- Graph paper of high precision (creation Jackie Sculier)

- I added a Layer of protection (to protect the preceding option from the burns of wire, spots of adhesives, blows of cutter and other aureoles of coffee cup.....) out of glass of 2 mm cut to measure with the coutour of the corner (to pass the edges to the average sandpaper for step to cut itself)