Friday, 29 January 2021

Diy Nexorades

 

As Christmas Decoration

Dodecahedron / Icosahedron as garden decoration

Cube Stack

Octahedron Stack




Variable volume stack

Octahedron and tetrahedron are equivalent with varying side lengths



Hosahedron Schematic

Hosahedron

Octahedron

Octahedron build process

Dodecahedron

Dodecahedron build process

Used in the garden as tomato stakes.


Hi

About 6 months ago I started working on some homemade constructions using 3d printed jigs - I may have seen a few similar things before but didn't know what they were called. Eventually I found out they were rotegrities or nexorades, so was able to research about them and write an academic article. Eventually that article was rejected.

I don't want to go through that rejection again, so am just self-publishing through this thingiverse link .

Anyway the link has instructions, 3d printable files for some tooling, and a complete referenced blurb including instructions on how to make them. Have Fun!

Regards


Steve Nurse

 

 



Saturday, 23 January 2021

One piece construction kit

 

Dodecahedron

Reinforced Octahedron detail

Reinforced Octahedron

Solidworks screen dump showing diameter which fits with 120mm diameter cd's and a 12.5mm distance between cd edges and polygon edges.

Truncation shapes and side lengths for the polyhedra made from the kit.

Tetrahedron stack. From the bottom, the joins are shared edges crossing at node, shared face, shared truncation edges. Bit of dowel in the middle helps support it.

Dodecahedron

Calculation spreadsheet screen dump. The actual spreadsheet can be found here.

Hi

This post is bit of a carry-on from the previous one, and at least some of the pics in the previous post apply. I've released the STL file for a single piece construction kit which uses CD's, rubber bands and 2.6mm bamboo rods to make constructions - all the regular polyhedrons plus tessellations and other forms. This post is a bit of a pre-hack, writing down and drawing the geometry required for forming truncation sides in the construction. I've already done some work based on the hacks, making a truncation side for an octahedron which makes this construction more secure.

It does this by joining some sets of 3 sides to each other making a rigid form not present in most of the "pure" octahedron subassemblies. The square side construction is made from a bicycle rear cog.

Up till now I've made cubes, tetrahedrons, octahedrons and dodecahedrons using the cds-as-sides-method. I haven't been able to make icosahedrons yet but have a few ideas. 

Happy Constructing, Regards  Steve Nurse

Sunday, 17 January 2021

CD Clocks Part 2

 

Test Joiner 1

Test Joiner 2

Test joiner 3: a bit like these house and TV models.

Dodecahedron, elastic outside

Dodecahedron, elastic inside, detail and.......

The whole thing

Octahedron. There are large spaces between some of the discs and not many edge joins, so this configuration is quite unstable and hard to build.

Cube and tetrahedral clocks.

Tetrahedral clock, front, and

From above

Cube clock

Cube clock all packaged up in a bulk cdrom container

A simple derailleur, mechanically transparent or naked


Hi

As per the last post, I have been making Cd clocks for a year or so, but left the design alone for quite a while. I did build a few models or sculptures of televisions and houses though, and these were as much experiments about how to put slabs together and fun as anything else. I put the tv’s and houses on our front gate, the closest thing to a public art space I have.

After a while, I realised that cds could be used as faces of polyhedra by attaching “edge holders” to the cd. With “N” equispaced edge holders you would get the essence of an “N” sided figure: N = 3 for triangle, 4 for square, 5 for pentagon etc. Then the faces could be put together, and all the regular polyhedra could be made.

I tried a few 3d print designs, and for a week or two had several pairs of joined cd’s on the shelves. I was after something easy to print and extract from the printer, and easy to use, and not too damaging for the cd. This included edge holders that clamp by press fit onto the CD. Some of these holders used techniques borrowed from the “house” and “television” experiments, using tubes as variable length joiners.

In the end, I borrowed parts of the clock number design to make the edge joiners, and this immediately made the edge holders compatible with the clock designs. Late last year, I made a few sets and gave a clock to my friend Deb Callister when I visited her, and gave my friend George and daughter-in-law Phoebe some as well.  The parts all pack down quite neatly, and I gave Deb the whole clock kit packaged in a bulk CD-Rom package.

In the hybrid polyhedron / clocks, the edge holders take the place of some of the numbers, so it’s a good idea to stow the left over numbers somewhere safe! 

The 1978 book " The Penguin Book of the Bicycle" describes the bicycle rear derailleur as follows, "Part of its appeal may be that it is is mechanically naked; it is easy to see how it works just by looking at it and it can be taken apart and repaired with relative simplicity". I hope I have achieved some of that design elegance and simplicity with the cd polyhedra and clocks. More to follow.

Regards

Steve Nurse

Dodecahedron as lightshade

Tetrahedron stack. From the bottom, the joins are shared edges crossing at node, shared face, shared truncation edges. Bit of dowel in the middle helps support it.




Tuesday, 12 January 2021

Cd Clocks Part 1

 

7" record clock, front and

....back
Spool Clock


 

Cd Clock

Cd top and wheelset, see here for original blog post and thingiverse files.

Cd clock with some of its mates.

 Hi

For several years I've been making clocks using my 3d printer. This started here, with clocks based on part of the spool my printing plastic comes on. The parts to print this clock are available here on thingiverse. Each clock uses a purchased set of clock mechanism and hands.

 Since then the idea has expanded a bit, with clocks based on 7" single records and compact discs.   Every project has as its base something that might be thrown away or at best recycled, but the clocks use things (filament spool, cd, record) in an upcycled way. That is, in the clocks, the form of the original item is at least partially respected and used again.

Along with cds, records, printer spools and clock mechs, I use hair elastics (just durable rubber bands really) and bamboo skewers in these creations.

By the end of 2019, I'd made a few clocks and gave them away to my son, brother, friends, nieces and nephews.

Will post about more developments later.

Regards

 

Steve Nurse. 

Obverse


 

Thursday, 7 January 2021

Myrtleford Literature and Fashion

 

Pick of the bunch from op shop, Strolling Players by Mavis Thorpe Clarke with nice library stamps for 50c.

Heiner's Bakery, I am chatting to Santa and wearing my newly acquired shirt.

These were 50c as well. Have read most of John Wren Gambler (later chapters slightly boring) and all of Agatha Christie The Man in the Brown Suit. (manages to be a bit more exciting than boring throughout and features the Heroine surfing in South Africa)

Shirt about $3.00

More of strolling players

Hi 

 When  I arrived in Myrtleford, I didn't have a long-sleeved shirt, and that was sort-of-necessary as I was at the start of 3 days riding of warm, sunburnie days. The first shirt I bought was too small and I took it back, so I visited the op shop several times and picked up a few good books from out the front for 50c. each. Several other good shops and sales in and around Myrtleford, I didn't have a chance to visit them all.

Here is my post from 2012 featuring Myrtleford shopping. I still have most of the junk I bought back then. I think.