I was looking for some steel to make the base of my tensegrity chair and thought this bit looked pretty so I bought it.
It is approx 10mm solid square with the twisted spiral added. My first thoughts were to just cut straight lengths to act as legs and then weld them to the box steel to give me somewhere to mount the cable mounts.
Now I am thinking that it might look pretty if instead of two straight legs it just had one curved leg, a bit like a banana hook, welded to a strong heavy base.
and this leads to the questions.
1) How easy is it to bend cold rolled steel bar and does my home made steel former in the picture look suitable?
2) I guess adding heat (propane blow torch enough?) would help in the bending but is that likely to deform the metal / spiral effect or wreck the steels strength?
3) If I can bend it to the shape I want, what stops it carrying on bending?
Safety footwear.
Top work 🙂
You can see the colour of the top of the right toe nail. That would have really hurt if it was stuck inside steel toe caps
I think its going to look shit. Sorry.
Anything that distracts from the tensosity i think you should avoid.
Having said that i sincerely doubt that shitty clamp will achieve much have you got a proper c clamp?
Heat probably won't help and a blow torch will barely tickle a lump like that.
You also want it to be fixed down in someway.
Yes, I have a bench vice - the clamp was just to show the concept. I did wonder about the blowtorch, as you say it is a fairly chunky chunk of metal.
I disagree about distracting from the Tensegrity though. Instead of having two straight legs with a bar between them and the cable hung down there will just be a single arc of metal holding up the chair. Artistic differences 🙂
To the question of bending it though. Can I use the 8 feet of leverage plus scaffold pol on the end if I need more leverage to get it to curve around in a graceful arc?
Is it likely to continue to bend if I then sit 18 stone plus the chair on the end of the arc?
It is hard to show 3D in MS Paint but sort of like this
Gargle:
"cold rolled steel properties"
In terms of physical characteristics, cold rolled steels are typically harder and stronger than standard hot rolled steels. As the metal is shaped at the lower temperatures, the steel's hardness, resistance against tension breaking, and resistance against deformation are all increased due to work hardening.
Depending on how it was twisted hot/cold and cooled it could be so rigid you cannot bend it
without serious heat , or just about possible.
The twisted element just adds to the complexity of how it bends and settles.
So basically you will just have to try and see how you get on.
This could be interesting 🙂
Off to the garage with a selection of clamps and levers
watch out it could shatter/snap if its got really hard - ie if it feels springy and does not go elastic.
Give me a place to stand and with a lever I will move the whole world. - Archimedes
Got to give it to the old fella, leverage is strong stuff. Turned out to be quite easy, in fact I am now a little concerned about the weight bearing capacity so might make up some decoration bracing that hopefully won't detract from the simplicity.
Finishthat - I was videoing it so that the medics could see which bits went where
First Loose fit
All that remains now is to work out the main strain cable, all of the support cables, fit the upper legs into the seat base, weld the lower support into place, add ornamental bracing, clean back, pain, oil or lacquer the wood, check that it actually works and then wait until next Thursday for the bin men to collect after MrsWCA has seen it and made her views clear, 🙂
Beat me to it - I was about to post that looked like crappy mild steel bar that was twisted hot so probably fairly easy to bend.
Cold Rolled mild steel as far as I can tell. It was labelled as 'threaded bar' and was a tenner from B&Q so I thought it was worth a punt
A result, Seems like it got annealed by hot twist, another way to check what it’s likely to do is with a file to see how hard it is , can range from super hard to putty soft.
You have the option to temper it and turn it stiff/springy , it could work depending on the design and .
Anything out of a DIY shed will be putty. It might have been cold rolled at some point in manufacture but that twist was done hot.
