Comments sought on new build: A CNC Router for RC Gliders and Planes

[njhussey]

Man wish I'd got £ for every time get asked this.. .Lol

That's £ I owe you then

What makes you think Ali box is any straighter or flatter than steel.?. .. It's not.!!

Just presumed that as lots have it for the Y axis that it was straighter, never used it really so presumed others knew best!!

In my experience steel box has just the same inaccuracies that Alu box does but steel is much easier to correct. Often all it needs is a quick run over with grinder knocking off any high spots, Low spots can be filled. Then just shim the rails to get perfect.

Can do all that in our works, Was thinking of welding some 50x5 flat to the 50x50 box and get a local engineers to skim the surface so it's flat.

If your using the Chinese round type rail then I can tell you with 99% certainty the base will not be flat or straight and will have more error than the steel your fastening it to.!!. . And thats without correcting the steel.!!

Nice, I look forward to that!

Have no fear of steel, it's cheaper,stronger and very easy to work with and manipulate to your needs. Other than being lighter Alu has just the same issues steel does and unless you have special welding equipment is actually harder to work with.
If you bolt together while bit easier to drill alu suffers from crush and hole deformation much more than steel does. Unless it's thick material doesn't hold tapped threads very well like steel does. Steel will easily hold fine threads in 3mm thickness for fastening rails etc and allow decent torque on bolts, try that in Alu.!

I have no fear of steel, it's my preferred material of construction as that's what we use at work to build the oil systems I quote, see the pic of a system we did for Ratcliffe Power Station ID fan blowers.