First of all thanks everybody for the participation to the thread.
Next i would like to introduce some of my conclusions and ask some things about all these that i have already read

1. I beam will not be used
2. For the rails support beams I am between these profiles
80X80 4 mm
80X80 5 mm
100X100 4 mm
100X100 5 mm
and for the table structure
80X80 4 mm or
80X80 5 mm
i want your advice


Jazzcnc wrote
Now regards the table Bed and getting it parallel to the cutter then don't worry this is not a problem.? Because every time you move the bed or in Fixed bed case Add the raiser block you MUST surface the table to be sure it's parallel to Cutter.
Jazzcnc when you say "MUST surface the table to be sure it's parallel to Cutter" you mean that the spindle should make a full pass over the cutting table and milling the table surface ?


Jazzcnc wrote
NOW what is VERY VERY important is that the X axis~(long axis) rails are on the same plane and not in twist.!! This is where all your efforts need to be concentrated on getting correct. The Bed could be Banana shaped and slopping at an angle it doesn't matter because after surfacing it will be flat and parallel to cutter BUT ONLY if the X axis rails are on the same plane. Any errors in this department affect the whole machine.

Several ways to ensure this but really only 2 that are realistic to the DIY builder. These are Epoxy levelling or adjustable top rail and careful measurement.
Epoxy is probably the easiest because it doesn't require accurate straight edges or equipment.! It's just more time consuming because of prep to surface to ensure clean and setting up dam walls and bridge etc . . .Plus it's messy and requires clean up afterwards!.
Here i have two question

1.when you say "adjustable top rail and careful measurement" you mean the X ( long) axis rails should be adjustable right?
2.when we talk about self leveling polyester epoxy, is it specific epoxy or common marine polyester can do the job. Should i need a primer in order the epoxy to bond with the metal?



Jazzcnc wrote
I recommend Digital drives with good resonance damping built in if building from steel. Also fill the Tubes with sand for best affect.
When you say "digital drives" you mean the motor drives. I reminds you that i will use 400watt yaskawa servo motors Sigma II generation, and i plan to put all the electronics not under the cutting table but to a separate enclosure in order to avoid vibrations for the electronics.


My main concern of using epoxy is the aging and the temperature effect to the table. I am talking about contraction expansion. The machine will be placed at my basement where i have temperatures from 8 ( winter ) to 26 ( summer ). Would that be a problem? What will happen if one day i decide to move the machine to another place. The truth is that epoxy look a good and easy solution, on the other hand i don’t fell good if i don’t have the ability to adjust. Also do we know how epoxy reacts. It is more than sure that epoxy doesn’t have the same contraction expansion ratio as steel. I have heard that pro builders that use cast iron, leave the metal for aging for 10 years...
Thanks again everybody. If anyone has something to suggest i am anxious to hear