CNC joint links

This topic contains 29 replies, has 9 voices, and was last updated by  David Walling 3 months, 3 weeks ago.

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  • #21848

    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

    Ryan
    Keymaster

    Nice!!!!

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

    #21860

    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

    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

    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

    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

    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?

    #22007

    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

    Jeffeb3
    Participant

    Nice work Barry.

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

    #22124

    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

    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

    Jeffeb3
    Participant

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

    #24933

    Renegadez
    Participant

    W0w this is awesome thank you for sharing!

    #34721

    Jeffeb3
    Participant

    I found a place where someone made most of the joints. Helps with the visualization, I think:

    http://mkmra2.blogspot.com/2014/08/cnc-cut-wood-joinery.html

    #34724

    Ryan
    Keymaster

    I love seeing them like that.

    I am making a new bed frame / headboard by hand (no cnc). If the system works out good I might make a few more with some cnc joints. In particular the headboard.

    I love the joints but a few that require fasteners would be cool as well, The dogbone overcut ones are not appealing to me, but the puzzle fit and stairstep ones are first on my list to try.

    #34727

    Jeffeb3
    Participant

    My couch has rectangular armrests. So I’m going to make a table that sits on it. I’ve been trying to decide which of these joints I’m going to add in there, purely as decorative elements. There are so many choices.

    #34729

    Ryan
    Keymaster

    Exactly, some logo shaped joints or anything crazy like that. I was putting serious effort into my headboard parts exact sizes very carefully with angles, etc. Cnc routing would have made it way better. Now I know for sure and need to make something super cool on the CNC for my headboard not out of a single plank.

    #34730

    Jeffeb3
    Participant

    I haven’t done this either, but the other thing you could do is cut out a template with the CNC, and then use a pattern bit on the router to quickly carve it one any gigantic object, like a headboard.

    I feel like you’ve been talking about this bed for a while. You really need to finish it so you can get some rest.

    #34736

    Ryan
    Keymaster

    Almost done, I only get an hour or so at a time.

    IMG_20170525_111523

    Allt the aluminum has been cut and welded, I am getting better at tig welding! The wood has all been cut, most of it has been glued. Just need to put the finish on it and do final assembly. Getting excited

    #34744

    Jeffeb3
    Participant
    I only get an hour or so at a time.

    I know the feeling. That’s why it took me two months to finish my Low Rider.

    Looking good. I really hate finishing. I have an unfinished picture frame I made right after I bought my first table saw. It’s been hanging above my fireplace for all 8 years or so since we bought this house.

    The last project I did, I used wipe on poly, and it was pretty good, but pretty expensive, and it did take like 9 coats. But it didn’t require a ton of sanding, or being careful when I applied it. Any time I can get away with a less tolerant finish, I use linseed oil, because three easy coats, and it looks good enough to hang up.

    #34751

    Ryan
    Keymaster

    Yes! The finishing is pissing me off. I much prefer the oils. That is why I have not finished the other cut pieces I am trying to decide if I should switch to tung oil or something I enjoy working with. I wanted the color but I don’t think it is worth the effort. That means remaking the headboard, with the cnc this time, kind of a bonus really.

    #34756

    Jeffeb3
    Participant

    Next time I need something to be water proofish, I’m going to make my own wipe on poly. That way it won’t be expensive, and the 9 coats kind of sucks, but if I can be liberal with it, and not worry about bubbles or anything, then I can just do one or two coats per day, and spend like 15 minutes on it.

    I have a project that I finished a while ago on my MPCNC, and I haven’t shared it yet, because I’m entering it in a plans contest. That’s the one I used wipe on poly for. I just submitted the entry.

    #34759

    Ryan
    Keymaster

    Interesting! Good Luck, and I can’t wait to see it.

    #34775

    Mike
    Participant

    Bookmarked. This is a great resource. It’ll come in very handy.

    1 user thanked author for this post.
    #34776

    Barry
    Participant

    I usually just put clear poly in my hvlp sprayer.

    1 user thanked author for this post.
    #34781

    Ryan
    Keymaster

    I miss having the ability to spray. Hopefully I can get a real shop soon.

    #34782

    Wayne A Hogue
    Participant
    Exactly, some logo shaped joints or anything crazy like that. I was putting serious effort into my headboard parts exact sizes very carefully with angles, etc. Cnc routing would have made it way better.

    Too bad you don’t have a neighbor or buddy with a CNC

    1 user thanked author for this post.
    #34785

    Jeffeb3
    Participant
    I usually just put clear poly in my hvlp sprayer.

    IIRC, you make a real mess with that sprayer. 🙂

    Are the cheap ones worth it? I was thinking about getting one. HF has a cheap one. I have a decent pancake compressor, but it’s high pressure low volume…

    #34804

    Barry
    Participant

    https://www.lowes.com/pd/Wagner-Flexio-590-Kit-Handheld-HVLP-Paint-Sprayer/4619636

    Have this one. So far I’ve put a few gallons of paint through it. I also have an older model, both work really well, but this one can spray undiluted latex. Though I still dilute it a little, too much orange peel texture otherwise. I’ve put about a gallon of poly through it too.

    #34812

    David Walling
    Participant
    I usually just put clear poly in my hvlp sprayer.

    <span class=”et_quote_sign”></span>

    IIRC, you make a real mess with that sprayer. ?

    Are the cheap ones worth it? I was thinking about getting one. HF has a cheap one. I have a decent pancake compressor, but it’s high pressure low volume…

    Mine is a cheap one. It might not lay the smoothest finish, but I haven’t noticed anything horrible with it. Be sure and get a good regulator. I use two. One of the big ones on the compressor itself, then one of the small ones on the air line right by the gun.

    My airbrush on the other hand…. spent way too much money on that thing.

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