Stell frame cnc 1500X1000. Adjustable table your opinion please

[JAZZCNC]

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

Any of those will be fine. Personally If mainly wood use then I'd go with 80x80x4 and save some money has it will be plenty strong enough.

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 ?

Yes exactly.

1.when you say "adjustable top rail and careful measurement" you mean the X ( long) axis rails should be adjustable right?

Yes exactly.

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?

It must be solvent free epoxy to avoid shrinkage. No primer is needed just very clean oil free surface also best if rough surface so epoxy binds to it better.

When you say "digital drives" you mean the motor drives. I reminds you that i will use 400watt yaskawa servo motors Sigma II generation

Yes sorry forgot you where planning to use servos.

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?

I've not had any problems with heat/cold, My workshop can go from -8 (winter) to 30 (summer thou rare here in UK) so don't think you will have a problem.

What will happen if one day i decide to move the machine to another place.

Nothing will happen everything will remain the same. Remember the Epoxy is not to level the machine.!! . . . It's just so the two rail top surfaces self level on the same plane.
To give an massively over exaggerated example.!!
Imagine the rails or the full machine before applying epoxy are not on level surface, lets say 10deg slope. When you apply the epoxy to rails they will self level on the same plane. Looking at the epoxy From the side it will have 10deg taper.
If you then move the machine to a level surface the rails will slope 10deg . . BUT . .They will still be on the same plane provided the frame is stiff and doesn't twist when you move it.
This is why My machine works in vertical position(15deg angle) because doesn't matter if the rails or bed are at an angle only matters that the two rails are on the same plane.

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.

The idea of epoxy is so you don't have the need to adjust.! . . BUT . .If you want the best of both worlds then have adjustable top rail and epoxy the surface has well. . . This way you can fine tune using shims if you feel the need.

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...

I've been using the Epoxy method for 3-4yrs now and I've not had any issues but if you want to be 100% sure and follow tradition then leave it to set for 10 years. . .Lol . . .( By which time we will have moved on to making DIY Star trek Replicators . . )

To be honest, as my english arent good , i dont understand excactly what you did
When you say "I put layer of plastic between rails and plate" what you mean? what kind of plastic ?

The layer of plastic is just a barrier to stop the top rail being bonded to the mounting plate so it can be removed. When the Epoxy putty has set hard the rail is unbolted and plastic barrier is removed and thrown away. The plastic can be any type, old carrier bag anything. Someone suggested to me taping the rail with parcel tape which I did try and does work ok.

when you say "between rails and plate" what do you mean? Your rails rest on a plate or on a square beam ? Sorry for asking but i dont get it

Look at the picture Eddy posted and you will see the plates which the rails bolt onto. Epoxy putty is then spread on these plates, then piece of plastic placed between rail and epoxy to stop bonding together.
I then set the rails on the same plane and parallel with a combination of temporary shims and adjusting bolts. Effectively the Epoxy putty is acting has a Permanent shim when dry.

Hope this makes more sense.?