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Thread: Shroud Design through FreeCAD

  1. #1

    Default Shroud Design through FreeCAD

    Hi All,

    I've been prepping to start building my first "serious" saber pair -- two-handed and shoto -- and I had something of an insight for an "easy" way to design shrouds for use. I figured it might be helpful to post.

    The challenge with planning a hilt sleeve or emitter shroud is the ability to design, or envision a 3d object and create a template for it. Taking a chop-saw or miter saw and cutting an angle off the end is all well and good, but something detailed is a bear. Using grid paper helps, but it isn't terribly precise. So, I'm plugging for the open-source software "FreeCAD" as a fairly simple means of designing a shroud. You can find the download links here: I'm not going to take the time to give a long tutorial on the software -- besides I suck at it -- but I'll give a simple explanation for some of the design work I've done in prep for this build.

    (1) Create a model for the sleeve material:
    Using Part Design workbench, start a part and make a sketch.
    Make two arcs with diameter constraints of 1.458in37.0332mm and 1.574in/39.9796mm (ID and OD for the sleeve material.
    Set a horizontal equality constraint between the endpoints of one of the arcs, and create lines from one arc endpoint to the corresponding endpoint of the other arc -- set vertical constraints on the two connecting lines.
    Set distance between the lines to 1mm or so. Smaller works, but I've made it work with 1mm.
    Use the "Pad Sketch" process and set the length to whatever length you want your sleeve to be. Here, I'm using 4.5in or 114.3mm.
    Screenshot (13).jpg
    Screenshot (14).jpg

    (2) "Cut" the model sleeve material to shape:
    Continuing in Part Design, create a new sketch -- or a series of sketches -- that form the tube into the desired shape using the Pocket tool. This can be tricky as using a flat plane as a cutting reference can be a pain -- though I understand there are ways of doing this more precisely in the software that I've not taken the time to learn. But, especially for simple emitter shrouds, this is not terribly difficult.
    Screenshot (15).jpg
    Screenshot (16).jpg

    (3) Turn the model into a "Mesh" and Unfold:
    Change over to the "Draft" workbench and create a "Facebinder" of the model. Select the Body and hit the spacebar to make everything invisible except the "Facebinder." Do the same with the last object before "Facebinder" (here called "Pocket"). If you don't make these parts invisible, you might end up selecting the "part" instead of the "facebinder" later on, and that's no good.
    Change to the "Mesh Design" workbench and create a "Mesh" of your newly created Facebinder. This will bring up a prompt that will require you to select the outer face of your model. Just click on it to highlight. THIS IS WHERE IT IS CRITICAL THAT YOU SELECT THE FACEBINDER AND NOT THE OBJECT FROM PART DESIGN! Once again, that is no good.
    Once you've created your "Mesh" select it, and use the "Unfold Mesh" command.
    Screenshot (17).jpg
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    Screenshot (19).jpg
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    Screenshot (22).jpg
    Screenshot (23).jpg

    (4) Create a PDF of your Profile:
    Open the "TechDraw" workbench.
    Select "Insert Default Page."
    Select your unfolded Mesh object in the list.
    Select "Insert a View." This will add the unfolded Mesh to your TechDraw page.
    Export the page to PDF.

    (5) Print:
    The most important thing here is to ensure that you set your printer to the correct settings. Make sure you are printing to a Landscape setting and are not scaling the document. This will give you an image that is to scale.

    ALTERNATIVE! -- Create a flat profile:
    Because it is awkward shaping a cylinder in this fashion, you can flaten your piece first and cut it from there.

    (1) Create a model for the sleeve profile:
    Follow the same process as before to create your base sketch. In this case, you are creating a rectangle with dimensions W: 4.945in/125.6mm (circumference of the cylinder) x L: However long you like -- My example is for a 5" long sleeve.

    (2) Cut the model for your sleeve:
    I recommend creating reference lines that help you to see the middle "third" of your sleeve and the middle "half" -- this will help you have an idea of what the piece will look like from the top.
    Note: The challenge with this method is that it is difficult to "visualize" how the sides of your rectangle will look once they meet. It is possible to turn your rectangle into a Mesh and fold it into a cylinder, but the most reliable method is to...

    (3) Using the same process as before, create a PDF of your Profile and Print:
    Turn your flat profile into a PDF and print it. Glue/tape the printed profile to your sleeve material and see how it looks. If you are not happy, you can edit it on the spot, or go back to your program for a "guess and check" method.

    From here, follow tutorial on Dremel-ing sink-tube parts to cut your part:
    Glue/tape your profile to the sleeve material.
    Cut it using a Dremel and cutting disc (or Band Saw/Miter Saw if simple enough and you have access to them)
    Clean it up with sanding discs. Etch/Engrave/Anodize/Paint/Powdercoat/insert-your-favorite-finishing-process-here.
    Means of attaching your sleeve include machine screws following drill/tap combo, or Epoxy/Gorilla Glue.
    So long as you're sleeving standard MHSv1 parts, your material should have a tight enough fit for the latter -- just make sure you put it somewhere stable while drying so that the glue can really set.

    Here are the completed parts for this build. Hope this is a useful tool for someone!
    Last edited by St0rm; 05-31-2022 at 06:40 PM.

  2. #2


    Rats! I can't upload all the photos at once... Oh well:

    (4) Creating a PDF:

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