building with steel tubing pre-welded plates with holes doable?

[Boyan Silyavski]

also after reading from an old thread on here i seen some people say to never rely on 3d drawings when it comes to actually putting the pieces together in real world.

That may be true if you don't spend enough time analysing your drawing. Not for me though. On my 2 builds and other stuff i designed, when i finish the design, i start assembling piece by piece the design in the building order, so i check if all elements are able to pass through and so on. So far had some minor mistakes like very difficult access once for a wrench so i needed my wife's help with her smaller hands to tighten a bolt.

What i said many times here is not to drill or machine for ball screw nut mount, spindle mount and similar from china, as they sometimes have different holes placement than drawings or a molded aluminum, so holes are not on exact place. In general until you have all linear elements / screws, nuts, end machining, etc./ at home to examine, dont start the build if possible.

what i mean is if i can get steel plates made and drilled from my drawings and then welded onto the steel tubing directly from the same company would i expect problems matching those holes to the rest of the gantry?

Same as above, and follow Dean's advice to leave always place for adjustment. My advice from experience is if you use steel laser or plasma cut for motor mounts etc., leave all pass through holes 2mm bigger diameter. Say bolt is M6, so pass through hole should be 8mm. As base coat, paint and adjustment will eat that 2mm.