CNC joint links

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This topic contains 11 replies, has 5 voices, and was last updated by Profile photo of Jeffeb3 Jeffeb3 3 days, 18 hours ago.

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  • #21848
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Check these out:

    http://www.flexiblestream.org/project/50-digital-wood-joints

    (I’ll just attach the .zip). These 50 joints are hard to view, because of the goofy navigatable pdf (I’m in Linux, so the links don’t work because someone wasn’t careful with their Caps Key… grumble grumble). But there are dxf’s for all the different joint patterns, and they are broken down into categories for joining panels, frames, and extending frames. Someone with some time and scraps could make a neat display of the different joints. It would be nice to have that kind of time, eh?

    I found it from this make page, which also has some examples:

    CNC Panel Joinery Notebook

    Also links to:

    CNC Joinery Notebook: Update 1


    This one has some neat examples. Just getting ready for those full sheet crawlers. 🙂

    #21858
    Profile photo of vicious1
    vicious1
    Keymaster

    Nice!!!!

    I need a new page for this kind of stuff. I need an intern…

    #21860
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Just be careful of the hidden costs of interns:
    – Engineering interns usually get paid.
    – They often don’t know anything, so they need training.
    – Bagels on Thursdays
    – Sexual harassment training.

    The list goes on…

    #21906
    Profile photo of David
    David
    Participant

    Anyone know how to effectively integrate these into CAD designs? Particularly the 3D hidden joints and such. This is *the* reason I’m building my MPCNC.. Yet I still have no idea what to do with this in terms of software, save perhaps recreating it in OpenSCAD.

    #21907
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Oops, I only attached the 4 examples. You really want the big zip.

    Once you have the right zip, unzip it, then find the .DXF file for the joint you want, you can either:

    – Use something like libreCAD (my personal favorite for 2D CAD) or OnShape to import the dxf, and move the parts around on your larger design. This is the C_001_2.DXF file opened in libreCAD:

    or
    – Load it straight into your CAM software, like EstlCAM, and just make the CAM software make only the joinery, save that tool path, and then have the CNC cut just the joint. You’ll have some work to do to make sure everything is lined up, and you will want the tool paths to only do the joint, not cut the piece out completely. This is that same file with the tool paths layed out in EstlCAM.

    You can see on the left part that what I’m doing is just cutting the edge out. Since I don’t want it to cut the entire part out, I couldn’t just use the “Outside” tool, I had to actually do engraving, and click the points around on the trail I wanted to cut. Now that I look at it, I should probably have made the two shoulder cuts as well. The benefit of doing it like this is that you can just attach a 10 foot board, and just make the joint on the end. There are a lot of gotchas though, because you have to worry about:
    – Getting the width of the joint the same as the width of the board. (and scaling the hole with the key the same way, so that they mate when you are done).
    – Getting the joint in the right place on the board
    – Getting the board perfectly parallel to the x axis (in this case, you might need to be aligned with something else in some other case. (Use the CNC to help you here, you can have it cut some holes for dowels in a perfectly straight line along the x axis, or have it carve the edge of a “fence” board.)
    – Getting the origin of the toolpath in the right place when you start cutting.
    – I would do this by moving the “Zero” in EstlCAM to a place on the joint, like the bottom of the board, on the shoulder cut.
    – Move the machine’s head to be touching the material, directly above where that “Zero” should be.
    – Reset the zero position of the machine (by selecting the option with the LCD, or power cycling it).

    Either way, this won’t be a 5 minute deal. You’ll have to learn some tools and understand their issues. It’s doable, but this is really a case of “what works for you”, not a “here’s a step by step”.

    If nothing else, if you want to start working in something like openscad, then you can just design the joints yourself, using these as inspiration. I _think_ openscad can support reading in DXF files. I know it can output them.

    #21908
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Here is the big zip.
    Ungh, too big… Oh well, here is a link to the zip in it’s original home:
    http://download.flexiblestream.de/Digital_Wood_Joints_Complete.zip

    #21940
    Profile photo of Bill
    Bill
    Participant

    Interns:
    You’d think if they are already in college they wouldn’t have to get trained for sexual harassment, didn’t they learn that in high school?

    [I know, not quite PC]

    #22007
    Profile photo of Barry
    Barry
    Participant

    https://goo.gl/photos/gScYdiP8AjdtS8NZ7

    Not bad for a first try. Hard part is getting the cut to line up with the end of the wood!!

    #22108
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Nice work Barry.

    What did you think? It looks like the joint is a bit loose? Does it feel strong?

    #22124
    Profile photo of David
    David
    Participant

    I wonder if maybe you need to have one side offset slightly to account for the width of the bit? Maybe make the “male” piece a little oversized so it takes a bit of pressure and even some sanding to fit in place? Overall I think it still looks like a nice wood joint, even with a bit of extra space.

    #22137
    Profile photo of Barry
    Barry
    Participant

    I think I might slow down the feed rate a bit. I think the bit is pulling into the wood because it’s moving faster than it cuts, but just a theory.

    #22140
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    Agreed. It does look nice. Try doing that with a chisel!

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