Our grandson turned 1 a few weeks ago, and our son Ewan, his partner Phoebe, and Phoebe's mum Helen organized a gathering at my Mum and Dad's place. Helen had picked up her mum, Grandma Paddy from Ballarat which was quite an effort. Mum, Dad and Paddie aren't too mobile these days, so having the party at Mum and Dad's made sense.
It all went well. My partner Christine and I are tremendously proud of our family and how they're making their way in the world.
Regards
Steve Nurse
 |
| Finished! Octahedron with large Holey Dollar (side) and small Dump (truncation) construction. 8 Holey Dollar sides and dump truncations. 3d printed hinges surround each face, and geometry is determined by the truncation diagram and table shown in an earlier post. |
 |
| Octahedron with cd sides and nexorade knitting of vertices as support, see here |
 |
| Octahedron with cd sides and bicycle cog truncations, see here |
 |
| Holey Dollar and Dump, a historical coin system from New South Wales. |
 |
| A glued pin from bicycle spokes and spoke nipples are the edges / hinge pins. Here, some cut up spokes are ready for processing |
 |
| Spokes with spoke nipple in place and cropped for length. Nipples are superglued to the spokes. |
 |
| Holesaw set, trial Holey Dollar and Dump. |
 |
| Measuring parts and dollar blanks. The disc od's are used in hinge designs. |
 |
| Drilling the dollars |
 |
| Cube made from dumps. |
 |
| Ready to assemble. Half hinges are held to sides by hair elastics (strong rubber bands) |
 |
| Halfway through |
 |
| Done! |
Hi
For a while I've been making platonic solid shapes using circles as sides. After a while, I realised that 2 of the solids - octahedron and icosahedron - are hard to make using this method because the sides don't join together in reinforcing triangular 3d groups. For these solids, some reinforcing is needed, and truncation works well. Here are some octahedrons I made before: one here with bike cogs as truncations, and this one with knitted corners.
Since making those constructions, I've improved the edge pins by making them from threaded bicycle spokes, and they don't come out now!
So this post shows the latest version. A few days ago I worked out that the octahedron truncation circles could come from the face circles, it just needed a bit of calculation to work out whether the sizes I could make with my holesaws would work. And I found a suitable size, did the 3d cad and printing required, and a few days later, voila it all works. The construction reminds me of the Holey Dollar and Dump, an early New South Wales coin set where a small coin is manufactured from the centre of a large one.
The same construction pattern could be used for a truncated icosahedron - a version of this one - but that is quite a bit bigger.
For now I want to make an octahedron with dump sides made by drilling the main sides off-centre. This will make the truncation sides have 2 holes, making clues as to the origin of the truncation sides. I can just make and varnish the sides, and use the pins, hinges and hair elastics shown above. Otherwise I can make the whole thing which involves being a slave to the 3d printer for about 24 hours. At the moment I'm inclined to make it from scratch.
Regards
Steve Nurse
Regards
Steve Nurse
Hi
There have been a few energy efficiency drives here in Victoria, and one of them has been free replacement of incandescent and flouro lightglobes with light emitting diodes. And our household has been offered that several times but we have declined, but one day I will do the job myself. Anyway I decided to another small energy saving job, and that is to put a switch before the transformer of our paper shredder. In its existing setup the transformer is always powered and warm.
The shredder had already been modified, it used to have a small plastic bucket, but that's been replaced by a large wooden one. There was an old light switch outside and yesterday I bit the bullet and did the mod. It all works ok, I'm happy with it!
Regards
Steve Nurse
Hi
This is a post about something I made years ago, a conversion of a Radiogram which originally had an AM radio plus mono record player, to an up to date music player which plays cds, cassette tapes, am and fm radio, records and digital files via usb or sd card.
The unit looks good and works well, and it's mainly used for playing records. We gave an EP of Old Man River by Paul Robeson a go a week or so ago.
This is the second stereo system to go in the case, and this one came from Aldi, cheap and cheerful as stereo systems go, about $300.
The radiogram was cut at the top to give access to the record player. Its a bit rough and I think I could do more work to improve it, but its ok for now.
Regards Steve Nurse
 |
| Pvc pipe as seedling snail protector in the garden. Not recommended, snails have still eaten our bean seedlings. |
 |
| Triangular sides from 27 inch bicycle rims. I first made one a few weeks ago, and the over / under rim pattern and its inspiration is shown here. |
 | ||||||
| Southern Bearings helped me a lot! They didn't have what I needed, but were happy to get it in, and I was able to pick up the m6 tee nuts a few hours later. Much better service than a couple of other shops. |
 |
| 3 sides lashed together using new pvc pipe and velcro. |
 |
| Which is the killer ap, this clothesline........ |
 |
| or this bike stand? |
 |
| Anyway, my wife Christine and her friend Chris like the clothesline. |
 |
| These are the sides. The large tetrahedron needs to be take-apartable, otherwise it would have to be removed from the house by putting it over the back fence. |
 |
| One of the sides together with the creation from yesterday's blog post. |
 |
| Fitting the sides in the back of our Kia Rio. It needs a bit of limbo to get them in, but they fit. Just. |
Hi
Following on from making a one-rim per side tetrahedron from cycle rims, I've gone ahead now and made a 3 rim per side model. I had made a side several weeks ago , and it had been sitting round till I got motivated. Building a small tetrahedron proved to be the catalyst, I just continued on from there and made the larger version. Plus I thought it would make a good cubby house for my grandson, or maybe a couple of grand-nieces and nephews.
So everything I've done with cds (125mm diameter) should also be possible with bike rims (about 650mm diameter), for example, the top join in the cd tetrahedon stack shown here is a part of the clothesline app shown above. There is a triangular truncation of the tetrahedron corners, and the 2 tetrahedrons are joined using this truncation. Anyway, I'll try to put some more details of the construction soon.
This construction was mostly done by seat of the pants, that is position things against other things, then mark and drill and saw accordingly. But not entirely, I did some graphic assisted calcs on what the angles between the sides of tetrahedrons are to work out hole positions, see below. Also I only made 3 tetrahedron sides, the 4th is virtual or implied by the edges of the other 3, or the ground becomes the other side.
Regards
Steve Nurse
Update, Nov 21, 2021
The big tetra has been updated with a complete spoked wheel with a cd turbine, and put on impromptu display in Batman Park during my regular Saturday volunteer session for Wecycle. Story with video in bikes blog here .
Regards
Steve Nurse
Hi
A while ago, I realised that if cd's and other round things can be incorporated into tetrahedrons and all the other platonic solids. And really, there aren't too many limits on that, and any disc or hoop could be built up into the form other shapes. Up till now I just did small parts, but I wanted to demo something larger for some writing I was doing. Months ago, I collected some 27" wheels from the Ceres bike shed, and for the most part just stored them.
So here are the results of a first experiment making a solid from a bike rim. The 27" rims seem to be all drilled with 36 holes plus the valve, and that makes it easy to space the rim joiners (about 100mm of 50mm diameter steel tube in this case) and it all worked ok. I used 3/16" bolts for this, and the spoke holes had to be drilled out a bit to take these bolts but that's not hard.
It takes weight fairly well, I'm 80 kg or thereabouts and can sit on it fine.
All for now, regards Steve Nurse