Borromean Ring table and pot stand.

 

Hi, 

Back in a design post here,  I mentioned making Borromean rings from bike rims, and in this post (ta da) here they are, not only made but also put into applications, a table and a pot stand. 

The rings are a set of 3 linked steel 27" bicycle rims, and one of them needs to be split apart, then rejoined to make the construction - I will do a making-of post later as I don't seem to have photos. The first app was as a garden ornament over a pot plant, and later I made a table.

Then I used the rings as a pot hanger, and I had the idea of using the construction in a floral display competition at the Ivanhoe garden club September meeting. Trouble was I know almost nothing about plants and called for assistance from friends with the plant to display. M was able to help by providing a pink Primula.

I elevated my standard (ok its rusty, take it or leave it) presentation of the rings for the garden show by scrubbing, then priming and painting the rings. They came out well and (woohoo) I won equal 2nd prize in the open section. A truly spectacular display won my section.

This was quite a good experience, I wouldn't have presented this work here, or properly at  all if hadn't been for the garden club competition.

Refined tangle

 

New set of tangles on 3 part cross shaped jig. The red rectangles were strapped to the jig, then the blak and orange squares added.

New tangle parts, The previous version used 10cc of material, and this new version is down to 7.3cc.

Tangle with some extra bits added

The whole thing from the side.

M6 bolt threaded into hole

Mod to hole positions was .....

The last thing done and it enabled this construction.

Over the last few weeks I have been refining my orderly tangles design, and started making good progress on a revision in the last few days. Initially I was helped by my young grandson, he busted some of the original parts, which prompted me to change some things. 

I've hollowed out the straight sections of the main part in a way that does not require support material when 3D printing. This opens up new holes in the design making some free form structures possible as a secondary use of the parts. This is a lot simpler than making the orderly tangle!

When fiddling with the designs I realized the assembly jig could be changed to make more structures possible: the outer holes of the assembled jig could line up with the holes in the square halves. That change has been done now and the new designs are up on thingiverse. Another nice coincidence is that the holes in the jig and the main part will accommodate an M6 thread this means that a hole can be converted to a stud in the playful assemblies. Download the files here, https://www.thingiverse.com/thing:7366096 

 

  Regards Steve Nurse

Drunken Walk

 

Hi

Mainly to amuse myself but also to potentially create something interesting, I have been doing a small amount of Excel coding, script writing and Bricscad script running to create some random or drunken walks. This is the path someone might follow if they take a step, then another step in a completely random direction, then repeat. 

This is not new to me or to others, and I found a good article about it here . I'll keep going with making some patterns - I should be able to write a 3d random walk and also change colors and line thicknesses randomly. Time is another dimension that can be put into the walks - at the moment my script has a half second delay between drawing lines which lets the drawing play out like a slow animation. 

The scripts are just an automated version of what you'd type into bricscad to draw something and are text files with a .scr filename extension.

See how I go on this, might report again later. 

More Tangles

 

Hi

I have done some more work on tangles, again replicating a tangle shown in Alan Holden's Orderly Tangles. This is a physical, 3d version of the Borromean rings link, and I chose this one as it gives a foot in the door for calculations of the geometry of other tangles. I chose a 9mm diameter for the half-hexagon as this allowed for a 3mm groove with 3mm walls on each side. The groove does 2 things: it reduces the amount of material in the part and the stud at the end clips into it. This was fun to make and I plan to make a bike wheel version of it soon. A model from a golf ball and rubber bands helps show the tangle's Borromonean rings structure.

The part can be downloaded from thingiverse here . 

 

An orderly tangle

A paper version, I haven't made this yet, just cut the pieces.

Hi

After a few weeks of trying, I have managed to make my first "orderly tangle" or "regular polylink" which is a type of link (lots of loops tangled up) made by rotating and interlinking regular polygon shaped loops on the face of a solid. These shapes are described in a book by Alan Holden called (unsurprisingly) Orderly Tangles.  I have written and submitted an article on twin edge polyhedral links and knots (see my last post ) , and during the review process, Holden's work was recommended to me. After resubmitting the article and also seeing online examples, I decided to have a go myself. There are articles by George Hart describing paper and other tangles here and here , but the one I made was based on Alan Holden's work. From here I might be able to work out the maths of the things and could go on to make them from other materials (beer cans being seem to me the most obvious).

Anyway my steps were - 

* Get a copy of Orderly Tangles, I needed to do this for my article anyway.

* Work out what I wanted to make. (This was an easy choice, I had made topologically similar cubes before)  

* Look up the dimensions needed and stick to the proportions - I used 1/4" = 10mm as a scale.

* Replicate the squares Holden used in a 2-part 3d print - 2 identical C shapes plug into each other.

* Attempt assembly without jig (really hard, I mucked around and made "other stuff" with the 12 pieces instead.

* Go back to the original photo and work out the proportions of a jig - it could be based on a 16mm square rod about 100mm long.

* Design and print a cross-shaped jig that could come apart from inside the polylink

*  Strap 2 squares to the jig with rubber bands, and keep putting more squares on as per the photo. To assemble the last square in I had to crop the pin on each side by about 5mm, the fit was too tight otherwise.

* Disassemble the jig et voila!

Regards Steve Nurse

For my 3d print files see https://www.thingiverse.com/thing:7366096  

and to make the tangle complete to another design use the second file on this page,  https://www.thingiverse.com/thing:7194987/files . This was designed by Albert B. Carpenter.