Polyhedra

[Burkhardt]

Thought I post my latest project (actually I am working on it for some time)....

It started out that I wanted to make boxes that go beyond the usual brick shape but obviously anything other than a body with perpendicular joints requires compound miter cuts that become difficult to calculate and to make (or dangerous on a table saw when small). So I ended up with another software project to flat machine the faces of any given polyhedron (provided it is convex). That means it can do the common regular polyhedra (http://math.boisestate.edu/m287/wp-content/uploads/sites/4/2013/11/Weinberg-1-102711_jpg_630x171_crop_q85.jpg)like crystal shapes but also more complex ones like Buckyballs (https://www.uwgb.edu/dutchs/Graphics-Other/polyhedr/archpol0.gif). Irregular ones like faceted barrels, tubs, trays or coffin shapes should be possible as well. The software is still buggy and rough around the edges but works in principle

I made the first practical cut over the weekend for a Dodecahedron, a 12-faceted box (see pics below). Came out reasonably well for a first experiment in cheap softwood but I need to improve my glueing fixtures for better accuracy (normal clamps can not be used). This one was just held together by duct tape and the joints do not match up perfectly.

I am still wondering what one could all do with it, besides fancy boxes I can imagine a sphere chair, lamp shades, large faceted bowls or blanks for turned segmented ones, a geodesic dome dog house, wooden globes, faceted columns etc.

https://lh4.googleusercontent.com/-xeiEk_5-JOY/VjAORchFe3I/AAAAAAAAGA4/y70W7HJXwpk/w800-h424-no/1-DSC03358.JPG

https://lh5.googleusercontent.com/-IhLpD5baKac/VjAOSdHgqPI/AAAAAAAAGBI/-ymvTSTsp4c/w800-h351-no/3-DSC03366.JPG

https://lh3.googleusercontent.com/-QVyglglC7mY/VjAc47RVVmI/AAAAAAAAGBw/PMmSVSCvcWw/w713-h857-no/MainAndNesting.jpg

[myxpykalix]

Drill a few finger holes and you got a "Bizarro" bowling ball......who "gets it"?
Actually that's kind of neat....

[scottp55]

Neat G. !
First thought was lampshades and then reread and saw you had that.
Be nice not to have to depend on the angle of a bit for a tight joint.
Been thinking of lampshades with scroll saw(Desktop cut) patterns backed by Mica sheet for over 2 years now, and bit angle defined sizes was always a sticking point, and never quite liked one enough to invest the time.
Of course I never have enough time to play with the gadgets I Already have from you:)
Thanks for always posting these projects of yours Here!
scott
Oh, Noticed carpet tape. Going on others ideas on an intermediate tape, I JUST completed tests yesterday using 3 brands of duct tape stuck to wood BEFORE whacking it onto carpet tape. Gorilla brand duct tape was closest to Ace Hardware carpet tape for tack/hold down. Next was Duck Deluxe(?) brand, and then regular silver Duck brand duct tape.
ALL released cleanly, but Gorilla (black) was also the thickest(.02"), and allowed a clean cut all the way through the wood without cutting into/through the fabric for an easy off.
First production run today on buttons. Test was on a .25X1X2" piece of Maple sanded to 600G, and was fantastically simpler.

[Burkhardt]

....Oh, Noticed carpet tape. ....

Well, actually I ran out of carpet tape. Instead I stuck masking tape to the board blank and glued the masking tape backing with titebond to the carrier board. Kind of worked and good enough for the experiment but not recommended. The tape adhesive did not release from the wood and was quite messy to get rid of.

For future tests I will use proper tape. I also added a feature to the software for tabs so that small pieces are help in place more reliably.

[scottp55]

Good about adding the tabs G. !
Saw that tab box.
What does the "Skeleton" check box do?
Yep, tape adhesive my nemesis...you should see what lacquer thinner does to carpet tape:)
Nice that it has a nesting feature! Works reliably?
Thanks again for your stuff.
Make a nice little plant pot holder for my orchids, or a stacking set of THICK bench cookies for when I need to lift stuff off the floor to work from wheelchair easier.
scott

[Burkhardt]

........What does the "Skeleton" check box do?
Not yet functional but the intent is to allow for a cutout in the polygon face with defined width, basically making a frame with mitered edges instead of a plate. The other thing not yet finished is a feature to drill a row of holes along the edge so that I can "sew" large thin plates together where a glue joint is insufficient (like an old fashioned canoe). I thought besides improved stability it might look attractive when using hemp twine or manila rope.

[QUOTE]....Nice that it has a nesting feature! Works reliably?..../QUOTE]
Nesting works well. However, it is not a random nesting function. The nesting is controlled by even distance and angle steps between the individual parts.

After all, I am not sure where this project is going to take me and it is probably weird enough that it does not make much sense to publish. For now it is just an interesting engineering challenge and I want to use it for a few practical projects.

[scottp55]

Thanks G.
Neat idea of the holes if someone wants to spend the time. Think if I were going to do it I'd use synthetic sinew or Waxed linen twine as some leather stuff using those has lasted over 40 yrs for me with hardish use.
Really pretty when done right.
Also reminded me of a technique a MicMac lady taught me I used for a gathering basket once when tools were scarce(hithchiking the Maritimes). Boiled wood strips(like staples) similar to this quiver pic, and they dried in shape pretty rugged. It lasted one hard use summer with no problems.
Let me know if you need it "idiot checked" :)
Haven't quite gotten a perfect Guilloche button yet:( ,but thanks!
scott

[chiloquinruss]

'just an interesting engineering challenge' it is also interesting for us to follow along with you so we can see how you approach various problems and how you resolve them. Thanks for sharing. Russ