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How to sharpen a stick

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36 commentaires

  • Tim Heeney

    this is how i would 'long hand' do it.

    Note, in manufacture the cone end chamfer to a point is never going to produce a perfect 'circle' at the intersection with the helex.

    The process i describe is akin to grinding a point at an 'off hand grinder'

    It didn't work out as planned...the helex refused to be combined with a cutting object.

     

    I then detached surfaces from the helex spring and cutting triangle , then split those surfaces using intersecting surfaces, then combined the surfaces into a solid.

    I suppose a bit troublesome but the helex obviously has special properties that disallow end face eradacation.

     

     

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  • Jacant

    Copy and paste the surface. Pull the surface the length of the diameter (2.5).Chamfer the end (1.25).

    Move the end point. you could do a bit of maths here to determine the length, for the angle you want.

    Draw a line as reference to be able to snap to from the end of the tubes axis.

    Select the 'Cone' with the 'Move' tool, move the Anchor to end of line. Rotate.

    Depends on how precise you want this.

     

    Edit : There is no need for the temporary line. See last image.

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  • Tim Heeney

    or... ( but only in V4.0)

    Plane on spring end, place point at center

    Move point off face by rad size ( 45 deg cham)

    Ctrl select curve of end face and point - then click Blend >tick mark. ( makes separate part)

    Combine Spring and Cone parts.

     

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  • Jacant

    Nice one Tim. Yes that's the easy way with V4. Buk only has V2.

    The reason I showed it this way is because, if you try to pull something and it does not work as intended, then copy and paste the face and pull that.

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  • Buk

    Is it possible to attach .rsdoc files here?

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  • Jacant

    Only if it is under 2MB. You could 'Zip' it, again under 2MB

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  • Buk

    .rsdoc are already zip files, which I know you know, and I knew too, but I tried it anyway and zip.exe error was quite cute:

    zip error: Nothing to do! (Design2.rsdoc)

    Assuming it was <2MB, what then? Attach as an image file?

    (I think I already tried that and it complained. I can't remember if it was the size, or the non-image file extension.)

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  • Jacant

    Use https://wetransfer.com  get a 'transfer link' and paste it here.

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  • Buk

    Sort of finished, but I'm still not happy with the corkscrew itself. The point is not good, and my editing of the path in 3D to get the helix to join to the central shaft leaves something to be desired.

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  • Buk

    I'll look into the wetransfer thing tomorrow.

    I tore a muscle in my shoulder whilst bracing my fence against the storm at the weekend, and right now I need to take some anti-inflammatory and lie down for a while.

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  • Jacant

    Another method.

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  • Jacant

    Use the image as a guide. If you can scale the image to the correct size all the better. If not scale the solid to the correct size later.

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  • Jacant

    It may be best to 'Move' the end of the coil, rotated, so it is at 90° with the edges of the coil as shown.

    Then do as described above.

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  • Buk

    Here's what I came up with:

    I can post the technique I used if anyone's interested?

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  • Buk

    Jacant:Use the image as a guide.

    That image is of my model:

     

    The main part of the corkscrew, the helix is fine, but the point (was) straight, rather curving; That's fixed now.

    The other part of the problem is connecting the helix to the straight centre at the other end. Constructing a spline in "thin air" between the two in 3D is a painful and hit&miss affair; I've yet to find a good solution to that (yet).

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  • Jacant

    Buk. I can post the technique I used if anyone's interested?

    I will always be interested in finding new ways to achieve the impossible.

    Nice model, something to get your teeth into.

    There is a video somewhere, where a 'WoodScrew' is shown how to be drawn; I'm talking about the way the point is slowly curved to the end. It may give you inspiration. If I find the link I will share.

    Found it. in my Favourites/Bookmarks

    https://www.youtube.com/watch?v=eZffOtyuapI 

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  • Buk

    Jacant:There is a video somewhere, where a 'WoodScrew' is shown how to be drawn; I'm talking about the way the point is slowly curved to the end. It may give you inspiration

    Thanks. I'll take a look at the video later.

    Jacant: Nice model, something to get your teeth into.

    It a Pederini corkscrew which I've had for years and always admired.Having modelled it,I'm less admirable about the design, there are several weak points; but the casting templates were probably hand carved in wood originally in a bygone era, so one has to bear that in mind. And to be fair, its seen plenty of use without breaking, so it can't be all bad :)

    I've simplified the construction since I grabbed the following images, but the technique remains essentially the same. The numbering of the comments relate to the images, left to right, top to bottom: (And actually, having typed all that, you probably only need to look at the last 3 images to understand.)

    1. Construct the main helix by spinning a 7.5mm line around the origin (pitch 10mm length 45mm), copy&paste the edge and discard the surface.
    2. select a point at the end of the helix that's to become the point, and click Plane tool.
    3. Draw a 2.5mm circle on the plane and Pull it to a surface.
    4. Full pull the surface down the helix. (The cylinder tool also works but seems to create more problems later on v2)
    5. Select the end surface and Move/Path it back alone the helix 5mm.
    6. Go into sketch mode on the newly position end and project to sketch the edge (Note: Its centre in not the same as the origin of the grid.)
    7. Put a point at the centre.
    8. Create a pattern of 6 points to the edge. (delete the pattern.)
    9. Then replicate the outer 5 points around the centre.
    10. As shown I drew circles, but I now replicate a bunch ot 45° construction arcs instead. The benefits are that the construction arc stay separate as arcs, which means they can be used as guide curves when filling the surfaces later.
    11. Back in 3D mode, select the inner most set of points and arcs (has to be done manually, points first, then arcs!) and the Move/Path -4 back long the helical spline.
    12. The select the second ring of points and arc and Move/Path it back -3 along the spline. Ditto -2 and -1 the other two rings.
    13. The connect the dots, all lines ending at the end of the spline.
    14. (no image) Fill the surfaces, the the back and if everything has gone correctly, you should get a solid. If not, and many times I haven't, a close inspection usually shows I've missed the end of the helical spine and attach the last point of one or more lines to one of the others.

    It fiddly as hell, and to be honest, I wish I'd stuck with your method :)

    Getting the other end of the helix to mate nicely with the central shaft is even more complex. I might post technique later, but I doubt anyone but me would be stupid enough to use it :)

     

    Now to try it (the corkscrew) in Blender!

     

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  • Tim Heeney

    Jacant.

    That's a favourite of mine to...it gave me great insight into designing directly in X mode creating solid geometry by just using the sketch tools alone ( no pulling/ revolving etc) in 'advanced mode', plus an insight into using layers as well.

    The original post was by Spaceclaim. The above i believe is a low resolution copy.

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  • Buk

    Jacant: https://www.youtube.com/watch?v=eZffOtyuapI 

    Wow! But vids like that are a double-edge sword. It just reminds me just how much is missing from DSM!

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  • Tim Heeney

    Buk.

    No, it's all there...in  '>design spark options > advanced> auto extrude / rev sketches in section mode' must be selected...

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  • Tim Heeney

    Buk.

     

    This is possible in v4 Blend - just FYI... sorry i had forgotten this could be done. 3D Exploration has done a good video on this and blend limitations....

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  • Buk

    Tim,

    I was looking at the ribbon! Looking again, it might be possible to replicate that screw in (my version of) DSM... I'll have a go later.

    However, after watching that,Utube autoplayed this one.

    Now tell me nothings missing from DSM :)

     

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  • Buk

    @Tim: This is possible in v4 Blend - just FYI... sorry 

    Now your just taking the pissant. :)

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  • Tim Heeney

    Buk.

    Just thought i'd add this...of course as you know this without question.

    I like your model and also as Jacant, i learn from your modeling explorations...

    It's a shame you can't work with the latest version. V4.1 is out in next couple of months...

    Tim.

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  • Buk

    Finally, I'm ready to screw ;)

    Update: Shoulda said: "Ready to pop my cork"!

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  • Tim Heeney

    Buk.

     

    'this one' video unavailable...

    Agree totally that DSM is only a subset of full Spaceclaim capability ;) ...but what is there should work OK or because DSM is newer than much of the older Spaceclaim youtube video's, operations / functionality may have 'moved on' , some may say, 'moved backwards' to ...

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  • Tim Heeney

    'Doing' projects like the above 'corkscrew' to completion is the best way to learn...

    Feels good to complete it i bet.

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  • Buk

     

    Huh! Sorry for the bum steer Tim. (You in the UK?)

     

    The url is "https://www.youtube.com/watch?v=AlcgO_QxPj4"; the title is: "Top Ten Reasons to use SpaceClaim."

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  • Buk

    @Time Feels good to complete it i bet.

    Indeed. 'cept if I stick to my plan, now I've gotta reproduce it in Blender! Which is a whole 'nother ball'o'wax.

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  • Tim Heeney

    Buk.

    Sure DSM doesn't have all that Spaceclaim does but...

    Yes, no sheet metal - but you can still make sheet parts quite easily imo. Sure no special tab/ folding reliefs but manufacturers often have their preferred way to do things anyway.

    Yes, no Mirror function - but DSM does have some mirroring capability and with a little thought much is possible and ultimately all is achievable.

    Yes, no Repair tools - hmm, got me here. Bad imported models rarely came up for me in my brief career as i mostly did original design and 'KISS' principles kept my modelling simple as...

    Yes, no Keyshot - it was an extra anyway. It's still available to buy and import .stp models into it. My important output ultimately was numbers on drawing's and easy makable parts/assemblies/instruments. But, if i was a product design studio, i'd need all the 'flash' i could get!

    Yes, no Drawing / Exchange module , not unless you purchase it for DSM.

    Yes, no Facet manipulation / smoothing tools for .stl files.

    Yep, in the UK...

     

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