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Thread: Using a cnc router for ply on frame construction

  1. #1
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    Default Using a cnc router for ply on frame construction

    A lot of stitch and glue boats are built from parts cut out using a cnc router. These machines allow for extremely accurate parts to be cut, over and over again.

    These kits are pretty awesome and lots of people build boats from them, people who would never otherwise build a boat.

    The downside of these kits include cost of shipping large sheets of plywood, the requirement to fiberglass and use epoxy, and the cost of cutting the kit, which looks to me to be about double or triple the cost of plywood.

    So I was watching a video about using cnc to make a piece of furniture, where the builder made a template of the piece using a cnc router and then made the piece using a router table and a template bit. I thought this could easily be adapted to building frame kits for ply on frame boats. For each frame, a single hardboard template of the plywood gusset could be made, which could be shipped along with the transom--cut in plywood, stem profile template and breast hook or other reinforcement templates as well. If the plans include not just the length of the frames, but the angles of the end cuts, the builder just needs a miter chop saw and angle gauge. Or the kit could even include 4 to 6 inch long templates of the frame ends.

    It would be a lot less costly to ship, and the boat design could be built with polyurethane glue and screws and avoid glass. Perhaps using 2 sided mdo or one of the better plywood to make painting easier.

    The cnc could cut thin hardboard much faster than thick plywood and need only make 1 gusset template for every 4 gussets so only 1/4th the parts load. There could even be holes in the template to mark the screw locations.

    A boat like a Spira design could be built without having to layout the frames.

    Anyody with a cnc and the software want to make me a test kit?
    Last edited by TomMcKinney; 03-12-2018 at 09:31 PM.

  2. #2
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    Default Re: Using a cnc router for ply on frame construction

    I have no need for CNC-cut gussets. I cut them proud, install them on the frame, then trim them to their final perfect dimensions with a flush-trim bit. QED.

  3. #3
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    Default Re: Using a cnc router for ply on frame construction

    I really like the idea of CNC cutting as it applies to boat construction. I have now completed two boats that were CNC "kits" as you describe. Previous builds were from plans that sometimes had full size templates.

    Although the CNC hardboard templates would allow you to go to the router table for final shaping, if a designer includes full size templates then they have basically done the same thing with just one added step for you the builder. You have just shifted the burden from builder to designer and consequently increased the cost of the "plans".

    I will say that buying the full kit, although more expensive, ensures (at least in my case) high quality plywood is used and shipping at least here in the US is relatively cheap. My time is worth something, so I give up the ability to say the boat was built from a "pile of planks", but gain speed and accuracy that is more important to me at this point in my own development.

    I think the next phase that we might see is more designers releasing plans as files so that home builders who have access to CNC machines (as prices for machines keep dropping) can cut the kits at home. This saves on shipping, and CNC time somewhere else, but with economies of scale the material cost would be higher for the home CNC builder so savings are still minimal. This would likely help overseas builders more.

    Good luck.

  4. #4
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    Default Re: Using a cnc router for ply on frame construction

    I think the premise behind this thread is flawed as you can eliminate the need to cnc the patterns for use with your hand held router and just cut the actual boat parts directly.All it takes is using a cut depth equal to the thickness of your building material,rather than the pattern stock.A number of enlightened designers already supply nested sheet files for your tame programmer to work with.Having to extract the expanded shapes and do the nesting adds a bit to the job and creates a need to communicate the assumptions that have been made about cutter diameter.All in all it can be a much faster way to get your boat parts cut.

  5. #5
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    Default Re: Using a cnc router for ply on frame construction

    I'm all in favor of numerically cutting boats. Our boat frames were all CNC (Steel Construction) - this meant the "lofting" was done on the computer screen, and having the full model available while assembly allowed checking any diagonal measurements for alignment. If I was building in wood I would CNC all the frame patterns - it is an amazing time saver - if the boat was designed as a computer model.

    Cheers,
    Mark
    Last edited by Mark0; 03-12-2018 at 08:22 PM.

  6. #6
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    Default Re: Using a cnc router for ply on frame construction

    I'm not trying to get the parts done quick, I'm thinking about how to get them done cheap and build a boat without epoxy so that more people might consider building one. This kind of kit would be very minimal, not a full boat kit. Its like the shed kits that just contain special joist hangers, but here we only provide a copy of one hanger and you cut out all the hangers from plywood. Just like the old time full size patterns from Glen-L, but instead of a paper pattern, its a hard board pattern of the gusset and/or a few other pieces. that would mystify a new builder.

    This isnt about building a boat where the whole thing is optimized for cnc. Those boats are awesome and go together fast, but are stitch and glue with lots of epoxy. I really like how this technology is changing design and boats I'm specifically talking about older ply on frame designs and how a cnc machine can, for the least bit of money, reduce the complexity and need for tools so that novice boat builders can get their feet wet.

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    Default Re: Using a cnc router for ply on frame construction

    You can just as easy create a kit for screwed ply construction. Just need a better cnc than a basic 3 axis machine. Or use people with semiautomated machines. A sensible kit would include all components for the frames, stem, stern and deck framing, all cut, shaped and prebored. All longitudinals can be prebeveled oversize, than cut and scarfed to lenght but not glued. All the above can be shipped in a small package with some full size mylar patterns for the ply or even cut panels prepared for joining.

    I find one of the biggest problems a lot of people have is finding good quality wood and ply at decent pricing. The kit solves that and also enables amateurs to build with handtools only, and that's what most have.

  8. #8
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    Default Re: Using a cnc router for ply on frame construction

    Our we just skip right to the end....

    https://www.digitaltrends.com/cool-t...rinted-yachts/

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    Default Re: Using a cnc router for ply on frame construction

    For one-offs, using CNC or a router with patterns probably doesn't make sense. But in a community-boat-building program based on a simple boat (OZ Goose) and building multiple boats at a time, patterns and a router makes a lot of sense to me.

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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by BobW View Post
    patterns and a router makes a lot of sense to me.
    That is how I make numerous versions of the same shape.

    Here is how I cut 20 knees...http://boatbw.blogspot.com/2014/10/i...my-kneeds.html


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    Default Re: Using a cnc router for ply on frame construction

    What's this forum come to? Of the ten posts above, only one poster's number of posts breaks into the four digits and his wise comment was that the idea was flawed. Big waste of bandwidth, Grasshoppers. Huge waste.

    There is no substitute for good craftsmanship. There is no free lunch. If you enjoy simply assembling parts like a moron on an assembly line in a mad rush to "get her done" at the expense of quality woodworking, well, go for it, I guess. I'm sorry, but "Ikea boats" seem antithetical to the entire concept of amateur boatbuilding. I realize your mileage may vary.

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    Default Re: Using a cnc router for ply on frame construction

    I've been a professional photographer for almost 20 years. One thing I have witnessed over and over is that nothing kills the enthusiasm of fresh minds in any industry or hobby than "old fart syndrome". What is OFS, simply the mentality that if you don't do it how "I" have done it for 50 years or how it's been done for 100's of years, it's somehow wrong. Having people participate in crafts, hobbies, industries in their own ways has one major factor, it insures that craft, hobby, industry survives. That survival will include change. Craftsmanship much like creativity comes in many forms.
    - John

  13. #13
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    Default Re: Using a cnc router for ply on frame construction

    I suppose I should feel I have arrived now that Bob Cleek has noticed and commented on a post of mine.I think cnc machining is a very relevant technology for boatbuilding as it expands the range of things we can do in a sensible timespan.It isn't of itself a substitute for careful craftsmanship,but it enlarges the range of things we can accomplish.It just needs careful judgement to decide where it might best be used.I suspect I am the only poster to this thread to have used a 5-axis CNC router and an adze on the same day.

  14. #14
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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by John Meachen View Post
    I suppose I should feel I have arrived now that Bob Cleek has noticed and commented on a post of mine.I think cnc machining is a very relevant technology for boatbuilding as it expands the range of things we can do in a sensible timespan.It isn't of itself a substitute for careful craftsmanship,but it enlarges the range of things we can accomplish.It just needs careful judgement to decide where it might best be used.I suspect I am the only poster to this thread to have used a 5-axis CNC router and an adze on the same day.
    Now, that's an accomplishment! Which one was the most satisfying? (Assuming you didn't swing the adze into your shin!)

  15. #15
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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by bnaboatbuilder View Post
    I've been a professional photographer for almost 20 years. One thing I have witnessed over and over is that nothing kills the enthusiasm of fresh minds in any industry or hobby than "old fart syndrome". What is OFS, simply the mentality that if you don't do it how "I" have done it for 50 years or how it's been done for 100's of years, it's somehow wrong. Having people participate in crafts, hobbies, industries in their own ways has one major factor, it insures that craft, hobby, industry survives. That survival will include change. Craftsmanship much like creativity comes in many forms.
    As a certified (or certifiable?) "Old Phart," I've seen my share of "enthusiastic fresh minds" walk into the wall of reality. Of late, there's been no end of that type posting questions that betray a complete lack of understanding and a determined intent to reinvent the wheel. Most think their "bright ideas" are original, but very rarely are they. More often, they are shopworn attempts to avoid learning the skills necessary. Coming up with new techniques and ideas is rarely accomplished by those who have not learned the basics in the first place. If you wan to play jazz improvisations, you'd better master your instrument first. I'm sure if this were a forum about fine art painting, there'd be guys posting that Rembrandt and Van Gogh were "Old Pharts" because they used oil paint instead of colored felt-tipped pens.

    There are always new techniques coming along in quality traditional wooden boat building. Plywood hasn't yet proven to be one of them in the last 75 years or so. The fact is, materials and techniques always change and evolve, but the wind and the waves are constants which are ruthlessly unforgiving. Anybody who thinks they've found a better way than the guys who spent the last couple of hundred years experimenting with wooden boatbuilding technology, and dying when they were wrong, needs to ask themselves what makes them think they are so darn smart.

    Like I said, if somebody wants to build a plywood boat and has fun doing it, that's a good thing. I've seen some really beautiful artwork done with felt-tipped pens, too.

  16. #16
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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by Bob Cleek View Post
    Now, that's an accomplishment! Which one was the most satisfying? (Assuming you didn't swing the adze into your shin!)
    Both tools did the job they were meant to do.I have to say that the adze caused more heads to turn when people passed by.

  17. #17
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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by Bob Cleek View Post
    . . .

    Of late, there's been no end of that type posting questions that betray a complete lack of understanding and a determined intent to reinvent the wheel. Most think their "bright ideas" are original, but very rarely are they

    .
    The lack of understanding is why some of us are here. We dont know how things are done and we are trying to learn by asking questions. Our ideas often come from our learning experiences, and when we see things are not sone like we think they should be we ask, then people who know better chime in.

    We aren't trying to reinvent the wheel, we just have wheels in our heads that we sont see around us, and need help figuring out why our wheel design is a crappy wheel, because someone else thought of it bwfore and proved it to be a crappy wheel.

    And sometimes, we actually think of entirely new ideas because we aren't directed in our thinking by how its always been done.

  18. #18
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    Default Re: Using a cnc router for ply on frame construction

    No matter what you may hear, don't stop asking questions or be dissuaded from proposing a new concepts. Some of us enjoy contemplating new techniques and discussing them with like minded individuals.
    I applaud you for trying to find a way to get more people involved in boat building. No one starts out with all the skills. We learn where and when we can. Thanks for asking this one.

  19. #19
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    Default Re: Using a cnc router for ply on frame construction

    Quote Originally Posted by TomMcKinney View Post
    The lack of understanding is why some of us are here. We dont know how things are done and we are trying to learn by asking questions. Our ideas often come from our learning experiences, and when we see things are not sone like we think they should be we ask, then people who know better chime in.

    We aren't trying to reinvent the wheel, we just have wheels in our heads that we sont see around us, and need help figuring out why our wheel design is a crappy wheel, because someone else thought of it bwfore and proved it to be a crappy wheel.

    And sometimes, we actually think of entirely new ideas because we aren't directed in our thinking by how its always been done.
    Fair enough answer. Regrettably, the internet is a questionable educational resource. It's full of good information, but, as you say, without some sound foundational knowledge, it's often very hard to discern whether what Google spews up is really any good or not. It's often hard to tell if a guy in some YouTube video is a master Boatwright who came up through the old apprenticeship program, somebody who just took a beginners' "wooden boatbuilding /course" someplace, an MIT professor, or some clown who just likes to hear himself talk! Starting by acquiring some of the "classic" boatbuilding books and studying them until you know them well is the best way to start. Consider Chappell's Boatbuilding and Boat Designing and Planning, L.F. Herreshoff's Commonsense of Yacht Design, McIntosh's How to Build a Wooden Boat, and Rossel's Building Small Boats. One book anybody who ever aspires to building more in wood than a few bookshelves really must get a copy of Tage Frid Teaches Woodworking: Three Step-by-Step Guidebooks to Essential Woodworking Techniques. (Profousely illustrated.) It's the best book for self-learning the techniques necessary to do just about anything with wood in the correct way... and with hand tools alone at that. https://www.amazon.com/Tage-Teaches-...es+woodworking Frid starts you out making a square cube of wood using a few basic hand tools and moves on from there. Just that first exercise teaches you to measure and cut with complete accuracy using basic tools. One of the greatest benefits of Frid's teaching manuals is that they free you from the fear that you need tens of thousands of dollars invested in a shop full of power tools to achieve master-woodworker-level results.

  20. #20
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    Default Re: Using a cnc router for ply on frame construction

    I am here for my lack of understanding, and the cleekster's condemnation. One takes the day with the night. And you can't buy this kind of entertainment.
    Last edited by wsgilliam; 03-26-2018 at 09:56 AM.
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  21. #21
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    Default Re: Using a cnc router for ply on frame construction

    The bad thing about plywood boats is that they don't hold up. They have been on the water for a century but I have yet to see one, constantly in the water, for even fifty years. Plank on frame lasts, for centuries if maintained, decades if abused. Cnc has no place in big boat restoration, anything that it cut out would have to be hand fit. Now a printer that made 24 foot 8/4 by 24'' clear Honduran Mahogany planks for 50 cents a board foot, then let' talk.

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