I have access to a free sheet of aluminum that’s 3/8" x 51" x 84". I’m wondering if I can sandwich two pieces of the aluminum together to create a 3/4" bed for the XXL. I could use Shapeoko to create countersinks and through holes in the top plate and then holes in the bottom plate and thread them. Then screw them together and maybe use some locktite for extra insurance on keeping them tight.
I’m new to this so I’d love to hear the community’s thoughts on whether I’m wasting my time or if it will actually provide value. Thanks!
Configuration: Shapeoko 3 XXL w/ Z-Plus and Dewalt DWP611 router
Cutting Plans: Mainly wood and occasionally some aluminum (for workshop jigs/clamps/etc.)
You could definitely do that and it should help stiffen it up. One thing you will need to consider is how flat the aluminum is. If it’s just mill finished 6061 it might not be flat and if you face it off it can move a lot.
I’ve literally done zero metalwork before. Do you mind explaining what you mean by it can move a lot if I face it? Similar to wood as in it may warp? Thanks!
Many metals have residual stresses built up in them depending on how they are made. When you cut a section of the material off, it will move to balance out the remaining stress.
The best example is a very long piece of cold rolled steel flat bar. If you put it in a mill and faced off one side of it, it will curl up towards the side you just cut off.
It’s kind of like if you build something that doesn’t line up in the shop, so you just put some 3" deck screws in it to squeeze it together. Then you decide you want to thin out part of it and start cutting pieces off of it. It will move as you starting removing material since it can’t handle the stresses you just put in the system.
In your case, it could warp as you attempt to face it flat. You might be better off bolting the pieces together first and then facing it. That would give it a little more resistance to warping.
Edit: Another example would be cutting something on a table saw and having it pinch the blade or riving knife. Even though you just cut an 1/8" groove out of the board, the internal stresses can squeeze it back together.
Thanks a ton - your explanation was fantastic. I didn’t realize that metal had internal stresses like wood. I haven’t received the piece yet so I’m not totally sure what type of aluminum it is. I’ll definitely check that out when I get it.