Steel frame for 8' * 4' cnc bed ?

[flanagaj]

Hi,

I am in the process of designing the bed for my CNC machine and would appreciate any guidance regarding frame dimensions and material choice.

My plan is to weld a steel frame together with 10mm * 50mm plate welded to the sides of the upper rails, which will then be milled by a local machine company in readiness to accept the linear guide rails. They have quoted £800 to mill the side rails and drill all of the holes.

Their machine is super accurate and will ensure that the rails are 100% parallel and level to each other, resulting in super accuracy. Whilst £800 is expensive it will save me the headache of getting the rails aligned

My plan is to base it on the axyz 4000 series machine as shown below.