News and Events

Keep up to date with Steve Nurse's designs and 3d printing.

Monday, 15 February 2021

Soccer Ball: Icosahedron from construction kit, part 2

 

Truncated icosahedron is...

Done!

My side assembly template. The hex side shown uses a cd, 6 joiners and a hairband / rubber band. Edge joiners must be evenly spaced to ensure it all fits together.

Interior. Yes an entire season of dodgy Grey's anatomy DVD's were used.

More interior

Constructing.

Making the .........

truncation sides

which are timber cut using a hole saw

Cd and timber dodecahedrons

Timber Dodecahedron. This is all the truncation sides joined together for a bit of a warm-up.

Hi

Tonight I finished the icosahedron I'd started making bits for. Quite an achievement I think, Lego Masters eat your heart out!

The bill of materials:

20 cd's

120 edge joiners for cd.

12 truncation sides based on holesawn timber,

60 edge joiners for timber

32 hair bands.

90 edge pins made from bamboo skewers. These are crushed at one end so they're a press fit in their slots.

The truncated icosahedron has the same form as a soccer ball, this one is not for kicking though!

regards


Steve Nurse


Saturday, 13 February 2021

Icosahedron from construction kit, part 1

 

Truncated icosahedron of the type I will be making.

This table for designing truncation pieces this was used to design the extra square sides of ....
this octahedron (about 42mm from edge holdes on squares to centres)


and the planned icosahedron faces....

with edge holders 57.2mm from centre.

The round timber pieces were cut using holesaws to cut through.....

3mm plywood.....

in this large drill.

Graphical image of truncations of cd polygons.


Hi, as described in posts here and here and here, I have been experimenting making regular platonic solids using cds as a base, but haven't yet cracked the 20 sided, triangle sided icosahedron. But a bit of work making a truncated, reinforced octahedron made me realise the reinforcing truncation sides could be made quite easily. 

The octahedron only needed 6 extra square truncation sides and I made them from bicycle sprockets of varying sizes. There was a bit of effort designing and making 3 different types of matching surrounds for the sprockets. With 12 truncation sides, the icosahedron really needed a uniform truncation side.

Eventually I wandered out to the shed, grabbed my big, (mostly intact!) holesaws and worked out which holesaw would cut the best truncation sides. Then I made a sample side, and designed and printed an edge adapter for it, using the spreadsheet and graphic 57.5mm measurement as one of the dimensions.

So the sides worked out ok, and I was ready to start making more parts. The round part of the truncation side came first, I was all set up to make that with the holesaw already in the drill. (to be continued)

regards


Steve Nurse

Monday, 1 February 2021

Double Ended Asym Surfboard

Some small scale models of the board. The fin position is at the bottom of the pic. Models downloadable from the thingiverse website here

 

Full size double ended Asymmetrical Shape in 3d cad.


Some design inspiration from my brother Richard's.......

homemade, handcarved......

Wooden Handski.

Fil from Jucsurf, I showed him my current carbon fibre asym board, (left) and he brought along a Juc Surf Carbon fibre reinforced model. My Asym is a reworked Trigger Brothers Windsurfer as documented here. Some of the design process for the new board is here.

Back in the day (ok, about 1990) at the same beach - a Mailibu (8 foot and over) surfing comp at the same beach - Left to right, Alan Atkins, Steve Hughes, Howard Hughes, Phil Trigger


Hi

For a long time I have been a surfer, and into my 30's I was over-obsessed by it.  It was only when I realised I could never when a world championship, and that travelling a 260k round trip to go surfing wasn't helping family life that I slowed down my surfing and became more involved in building bikes.

But my surfing has never stopped entirely, and I still try to make it down for a surf if I have the time and the waves look good.

Anyway, without bothering with too much yammering, I've now ordered a double ended asymmetrical surfboard from Jucsurf,  who make surfboards using recycled carbon fibre reinforcement.

I'd had the idea of the double ended Asym for a while. When you're surfing, the front bit of the board doesn't do anything, it just sticks out in the free air - so if you're going to make an asym board - which lessens the difference between toe and heel side surfing - why not make one end suit goofys (right foot forward surfers) and the other to suit naturals (left foot forward surfers). 

And the asym never caught on, maybe because conventional symmetry allows a board to be made and sold which suits goofys and naturals equally well, and needs no complex explaining. Well - the new board will suit goofys and naturals equally, as long as you switch the fin from one end to the other - but the complex explaining will become necessary! 

A post about a vintage Asym board from Shred Sledz puts some of this into perspective. Some of the post needs to be translated from "surfboard language" into "English" which most people will have some hope of understanding!

Shred Sledz: "The Carl Ekstrom asymmetrical surfboard measures in at 7’10” x 23 1/2″ x 4″. Wave count is not an issue on this thing!"

English: The surfboard is long and thick and so floats well. This means that for most people the board will float you out of the water, and most experienced surfers should be able to paddle it easily, and catch waves easily too"   

For this board: My board will be longer and just as thick at the Ekstrom which means it should be easy to paddle and catch waves. I am a bit old (60) and a bit heavy (83kg) but moderately fit and it was designed for me. See pic 6, some boards are much smaller!

Shred Sledz: "Unfortunately for me and all the other regularfoots out there, the tail on the Carl Ekstrom asymmetrical surfboard is designed for goofyfoot surfers. It’ll be hard enough finding another one of these boards in great condition, much less with the right tail configuration."

English: Even if I could borrow this board and have a go on it, its tail configuration would not suit me. With my left foot forward surfing the toe side rail is shorter. Asyms work in reverse, the toe side rail should be longer which evens out the ability of the board to turn on toe and heel sides.

For this board: With fin boxes on each end of the board, and the right sort of tail configurations, the fin position of my board will be adjustable between "suits goofy / right foot forward surfers" and "suits regular / natural / left foot forward surfers. This will involve swapping fin postions, a 2 - 3 minute job. See pic 1 of some existing models.



Regards


Steve Nurse

 

 


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.