Welcome to Our Community

Some features disabled for guests. Register Today.

Torsion Boxes!

Discussion in 'CNC Mills/Routers' started by Sage, Feb 2, 2014.

  1. Sage

    Sage Journeyman
    Builder

    Joined:
    Dec 14, 2013
    Messages:
    32
    Likes Received:
    60
    Thought I would start a thread dedicated to building/improving Torsion Boxes. Torsion Boxes are awesome and everyone should have one or two... here is a great video of an all wood build:
    http://www.thewoodwhisperer.com/videos/episode-18-assembly-table-torsion-box/

    Being super flat, and super strong they make great work spaces, but more importantly they make a great platform to build your CNC machine on!

    Since late last year, I've been kicking around a design for a CNC. I was already planning on using V-Slot, so Marks OX build was perfectly timed. Eventually I want to take this design to much a much larger size (~1500x1500mm), and according to my research that means one of the better designs is a fully supported X axis. And that means building a large support structure, and/or a Torsion Box...

    So I made one. Since I didn't have the woodworking tools to create perfectly flat lumber, and because I love aluminum extrusion, I made mine using V-Slot! Probably not the cheapest option, but I knew it would be super strong and flat. Here is what I used:
    • ~4 1500mm 20x40 V-Slot extrusions, cut down to ~750mm lengths
    • M5 Hardware all around (10mm and cut down 90mm)
      • Some standard M5 T-Nuts
      • Some 5mm wood T-nuts (these were a ***** to find)
    • 2x Metal brackets in the corners, and then printed versions on the interior to save a bit of cash.
    • 1/2 inch MDF for the bottom skin
    • 1/4 sanded plywood for the top skin
    Cutting down the extrusion was easy because I went out a picked up a chop saw. Obviously it's critical that you get all your external lengths identical so you end up with a nice square box. I had the skins rough cut at the local hardware, and then used a flush cut router bit to get them perfect after bolting the whole thing together.

    If I had to do it over again I would work on a jig to help line up and drill the vertical holes in the extrusion (I don't have a drill press so this was done by hand). I did use a printed template to space the holes correctly, but it still required quite a bit mucking about to get everything squared up. Now that its done, and I've drilled what feels like 5000 holes in some 3/4 angle iron so I can bolt my 20x60 to the new Torsion Box (more on this later) Now I've got a great base for my upcoming CNC machine!

    What do people think? How can we make this easier to build, cheaper, better, and/or stronger? PS - the reason I went with different upper and lower skins was so that I could eventually embed 2 20x20 V-Slot extrusions as hold down rails for the table. It will make more sense later I promise.
     

    Attached Files:

    Mark Carew likes this.
  2. CutAboveZ

    CutAboveZ Well-Known
    Builder

    Joined:
    Jan 1, 2014
    Messages:
    14
    Likes Received:
    2
    Looks good to me!

    I thought about doing the same, and priced it out. It became apparent a big chunk of the price of setting up a CNC is going to be the table. I don't have a flat spot in the shop, and dead flat by using aluminum extrusion looks appealing.

    To save costs I was looking at using aluminum box levels or screeds. The i-beam levels I looked at weren't very stable I could twist them. Online I found 3/4" x 4" x 48" aluminum screeds for $12 each. The screeds have handles so air flow could happen and this could be used for ribs in a vacuum table. Gluing the screeds down to the skins. If I could find some waterproof skins I could have a wet table. Maybe some boat building composite.

    I think I'd have the MDF or spoil on top and use the CNC to flatten it. After it spoiled, flatten it again. After a few times, flatten then glue on a fresh top.

    If I made a wooden table, I'd be tempted to level the ribs with the cnc before gluing down the top.

    With the v-slot, you open up a section of the table to clamp boards vertical to route the ends of boards if needed.

    So many choices - the v-slot makes sense as the table can be changed again and again :)
     

Share This Page

  • About Us

    The OpenBuilds Team is dedicated helping you to Dream it - Build it - Share it! Collaborate on our forums and be sure to visit the Part Store for all your Building needs!
  • Like us on Facebook

  • Support Open Source FairShare Program!

    OpenBuilds FairShare Give Back Program provides resources to Open Source projects, developers and schools around the world. Invest in your future by helping others develop theirs!

    Donate to FairShare!