Would this concept work?

[Boyan Silyavski]

I agree with that. Though the screws inside seem a good idea at first and even the connecting plate could be made quite stiff, there are some small details to be considered.
Like:
-tightening the motor belts and later visually inspecting them constantly. Ones inside it would be difficult to notice something is not right
-adjusting all that contraption, once the machine is heavy
-screws outside are almost at the ideal height for cutting with very short to none arm, to drive the gantry, once inside the arm becomes big, needs additional strengthening which may lead to need for Servo motors due to too heavy gantry

In short- all could be done but on a first build i would aim for simplicity, proven designs, easy to adjust. raising the sides of the table is not ok if you are in a production workshop and need a machine to lift heavy plates to the table. All else is a preferred design, shorter to none gantry legs and additional dust protection. Its proven, dust will not go on screw even without vacuum cleaner.

[amd7000]

Thanks for the informative replies. So running a couple of long belts on the outside shouldn't be a problem? I would probably use self tensioners if that'd work? I will check out Deans cnc, cheers.

Yea, I thought about access to the pulley after I did the drawing, haha. Not good. Could put a Perspex plate across the back where no cutting is going to take place, but whats the point. Could put some nice neon lights in there too,haha. :)

Would the top section of the gantry work O.K? As its easy to do, just 5 pieces of 120mmx60mm box section. Looks a bit crude but would add extra 8mm steel plate to support the top too.

Will keep checking other peoples designs as I agree with you guys by making a tried and tested cnc.

I've also seen your project 1 silyavski. Wow that looks like a beast! Very nice. But looks too expensive and heavy for what I want, also I don't think I'd be able to make something like that. Really want to keep the whole cnc less than 100kg.