Stell frame cnc 1500X1000. Adjustable table your opinion please

[Boyan Silyavski]

In my opinion your legs are overbuild and the rails support underbuild.

The I beams are bad idea.

After a lot of thoughts and considerations for me:
-a whole machine build from 80x80x3mm with a careful design could be the best solution for a DIY sturdy CNC
-a whole machine build from 100x100x3mm with careful design could be a real beast of a DIY extremely sturdy CNC

The people who build with more than 3mm thickness either have a design which is not so perfect or are pro builders who know what they are doing and definitely its not their first machine, usually some beast with a special heavy duty purpose


It would be nice if you take your time and read the entire Tony CNC build here where he started with similar to yours idea, the calculations of the price and weight, how he implemented and personalized the design from another build of mine adjusting to his dimensions and needs.


More or less i could say that the particular design of mine could hardly be beaten for strength, weight and $$$ combination, permitting the final result to be extremely sturdy CNC with deep 160-200mm Z travel.
The trade offs are that it is better to be all soldered and adjust the table bed by fitting thick table bed instead of raising and lowering the bed structure itself.
The plus is that its very easy to cut to size, one profile only, cheap, very easy to solder precisely and completely scalelable from small to big machine.
the gantry could be made from 2 profiles soldered together so finally will be 200x100 or 160x80, which both a are great and in the ideal range for 20 size supported rails

Its not tested on a finished machine, but i am currently building one and can assure you is steady like a rock. If you scale it, mind the distances between every element and don't change them, just add or take elements to make it bigger or smaller.
Its deceivingly simple but many things are taken into consideration.

Hope that it helps.

My advice is when comparing designs take the calculator and see the KG and what you receive for these KG in strength. Then compare. Every KG is an euro



PS. FYI just went in the garage and measured the deflection of my machine under 100kg weight/me/. Its very similar, with different measures. Table bed is 67cm wide and is 135cm long. So stepping on any of one the table bed beams gave me 0.05mm deflection of that beam and stepping on any of the sides that that support the gantry/supported at both ends only/ gave me 0.03mm deflection. So keeping the design and not under doing something when everything mounted will give you real life deflection which is unmeasurable/or for sure less than 0.05mm/ . So my machine with mine particular dimensiones with table bead mounted will have over all deflection of less than 0.01mm. isnt it great?