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IndustryArena Forum > Mechanical Engineering > T-Slot CNC building > 8020 extrusion dimensional accuracy
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  1. #1
    Join Date
    Jan 2016
    Posts
    25

    Post 8020 extrusion dimensional accuracy

    Not sure if this is the right sub, please let me know if there is a more appropriate one.

    Recently scored a great deal on a lot of 1530 (1.5" x 3") 8020inc extrusions. 16pcs, 48" inch long , 8 regular weight/smooth, 8 lite/ridged, all anodized black

    I want to build a modular, general purpose setup table.

    Doing mostly woodworking at the moment but may do a CNC gantry at some point (which may or may not be extrusions itself), but at the moment I just want a reasonably flat surface with some t-slots for holdown equipment.

    Any general advice?

    I am thinking I will do a perimeter of vertically oriented extrusions (3" face outwards, 1.5" face @ working surface level) with some intermediate extrusion members running cross-ways (3" faceup @ working surface) with MDF sections between. Also extrusion for legs with the faces planar with the outer perimeter.

    One concern I have is how to connect them squarely. The extrusion seem quite straight, but the faces are not very flat. E.g. measuring the max thickness I get 1.500 right in the center but as little as 1.495 outside of the t-slots, so it seems if I bolt up a flat angle connector it will a bit skew, enough to give 0.25" runout over 48" (by my simplistic reasoning)

    I do have a small desktop CNC mill and I could flycut the faces, 18" at a time, but that would a pain, and I would loose the nice anodized finish.

  2. #2
    Join Date
    Sep 2008
    Posts
    140

    Re: 8020 extrusion dimensional accuracy

    Could it be the 2 degree incline you are measuring?
    Larry
    Attached Thumbnails Attached Thumbnails 2 Degree.jpg  

  3. #3
    Join Date
    Jan 2016
    Posts
    25

    Re: 8020 extrusion dimensional accuracy

    I called my self measuring the maximum dimension, I put the jaw across the whole surface.

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