Building a Spreader Bar

My good friend Andrea has come up with a rather clever new aerial apparatus called Flyweight Chains involving a bundle of chain of similar mass to to the performer's body weight acting as a counterweight.

The chain is attached to a steel cable the other end of which is attached to the performer, the cable is then suspended from the ceiling of the venue by two pulleys. The result is the performer being almost weightless...

I started getting involved on the edge of the flyweight chains project around about the time of Andrea's debut performance at the Wellington Circus Trust Christmas Cabaret performance back in December 2011. My involvement at that stage was filming said debut performance:

Now the main issue with the system has been, the pulleys have to be rigged a very precise distance apart with the correct orientation to the audience. At cabaret this wasn't an issue however the requirements have limited the number of possible locations that the apparatus can be successfully be setup.

Andrea mentioned to me that  a spreader bar of approximately 1800mm in length would allow the apparatus to be rigged from a single suspension point... As a bonus the whole rig can also spin....

It was time to do some good old fashioned engineering; Jez, (rocket scientist) Andrea and myself set about doing some design work. That was after some rather NSFW trawling of the internet for all information possible on spreader bars, it would appear that such a piece of apparatus isn't just used for industrial lifting purposes...

After many many many different iterations, the design we can up with was to use plain and simple steel pipe for the bar with load rated eyes at the ends. Jez's rocket science method and my "use the scaffolding standards" both came up with a bar that would be good for approximately 2 tons in compression.

The cleanest way to buy load rated eyes off the shelf is to use either shouldered eye bolts OR eye nuts, we chose to go with eye bolts that would screw into threaded sockets in the bar. Said sockets are M20 threaded rod coupling nuts, modified slightly on a lathe and welded into the ends of the pipe.

Buying the coupling nuts turned out to be a lot cheaper than an equivalent piece of steel and cutting the required M20 internal thread.

The final result showing the pulleys, top cables and the free running steel cable.

The whole spreader bar and cable assembly was then proof tested at Steel and Tube... They issued the bar with a shiny test certificate proving that it had been tested to 500kg with no signs of distress.

Below is the creation in action at The Life You Imagined show in June 2012.



Also see: Andrea's blog post on this spreader bar.

New Cannon

This creation is a new attachement built to go with the pNuke system of pneumatic mortars. These have been used for such fun as attempting to break the sound barrier and all kinds of effects in Shihad's Sleepeater.

Mike Bailey put me on to The Rock's Perfect Pie challenge... To build the world's greatest pie launcher. The PiNuke was the result....

Usually all pNuke plumbing is 50mm, now I wanted the pies to be shot intact complete with wrapper for effect. This required the new barrel to be approximately 100mm in diameter to fit a Big Ben pie whole.

A length of 100mm steel pipe was sourced along with a 50mm to 100mm bell reducer and a 50mm male BSP fitting.

The parts were Tig welded together in record time (there was only a week available for the competition)

A quick video was shot and edited the next day just in time to enter, turns out frozen pies at speed inflict rather a lot of damage to microwave ovens...



















Fast forward a couple of weeks and I took the cannon away on holiday with me (weird I know) Zac, Jonathan and myself set about launching some nefariously fun projectiles such as fence posts with the cannon.

Fun with a cannon and cameras down on the farm

The cannon was strapped to an unsuspecting tree and much fun ensued... Of note: Dead leaves used as waddings and the flying soft drink bottles.

Rapman Extruder Conduit Clamp

For a very long time now the Rapman's extruder conduit has been attached to the frame with a couple of velcro cable ties:

I decided finally that the cable ties were a bit too crude and set about designing something a little more elagent. Twenty minutes later I designed a clamp:

 Now it was only then I realised that the clamp needed an offset between the threaded rod and the conduit. So I had to throw away the nicely rounded clamp and start again.

Mark two was a little uglier - The part needs at least one flat face with no overhangs. That is, the face which will be laying down on the bed of the printer.

A couple of hours on the printer later and these were the result:

Still not perfect (I misread the protractor in my haste) but it clamps the conduit and the threaded rod OK. Mark three will be the correct angle :-)

If I say so myself this clamp goes pretty well with the first one made for this machine.

Building a Ballet Barre

My Sister has been getting more into her ballet recently, she asked me about the possibility of building her a portable barre.

Not one to do things by half and being rather inclined to build industrial furniture and lighting, there was only one material to build this creation out of...... STEEL!

This will probably be the final use for my pile of 32mm steel pipe and matching Kee Fittings. The stash has seen in previous lives, use in a bed been a scaffolding in a music video and more recently as a frame to support the big scary light.

I set about cutting the steel pipe into the appropriate lengths with my friction cutoff saw,

and assembled the frame:

Presently the frame is sitting on four corner couplers, I intend to make something fancy up involving locking casters and perhaps some 3D printed clamps.

Breaking the Sound Barrier

Some friends of mine and I decided to have a bit of a farm get away weekend recently. One of the things we decided would be fun while away was break the sound barrier... With a really big cannon.

Some of you may be familiar with the pNuke system of air toys which have featured in videos such as Sleepeater... The cannon used here is a more powerful and scary version with a custom built valve and some other trickery.

Modified deluge valve fitted to the air tank.

Fire deluge valve with a 5/2 3/8th inch pilot valve.

The barrel is a 6m length of 40mm scaffolding pipe coupled to the pNuke via some very big rubber hose and Mikalor super heavy duty hose clamps.

Clamps securing the rubber hose to the steel pipe. 

Rubber hose coupled to the deluge valve.

Unfortunately we were unable to achieve supersonic projectiles, I think this is due to the maximum flow through the valve not being high enough or the interior of the barrel is too rough.


Despite this the result is pretty spectacular...

As usual, Glow Sticks are pretty impressive in the dark:

We made a projectile out of rolled up newspaper and gaffer tape... It promptly disintegrated when launched.

An attempt to fire a lemon resulted in a lemonade mist... No pieces of the lemon were found.

Putting the Light Into Proportion

The Silly Light has had it's first opportunity to really shine... Ahem.

As the gig was the first "final" assembly I wasn't 100% sure as to how it was all going to turn out... Jez and myself set about pulling the house apart in order to bolt the Kee gate hanger down.
The ironwork is a mixture of Unistrut brackets and a spare construction plate I had lying around. The end of the scaffolding pipe is inserted into this gate hanger to keep it in place.

The festoon lights were gaffer taped to the pipe just before we put it up.

After the whole thing was assembled, the pipe was propped up on one of my ammunition cases as the shade was hanging a bit low. The rope top stay was tied to the hand railing and it was done :-)

The effect is almost exactly what I wanted to achieve, if the light is assembled again I want to prop the pipe up higher and spread the light further.

Thanks to: Jez, Dave and Joel for helping with the assembly, Will for help with disassembly and anyone else I have been rude enough to leave out.

Part One: Where the idea came from.
Part Two: First testing of the light shade.
Part Three: I try out a mercury vapour light source.
Part Four: Procuring parts like the street light.
Part Five: Test assembling the frame.
Part Six: Going away from the frame idea.

Time for a change of plans.

Things have been a little quiet on the Light With No Sense of Proportion front lately... I've been too busy with my day job, rewiring a friend's house and being crook to work on it.

Anyways I finally hung the streetlight fitting inside the lampshade to try it out: Unfortunately it's not all good news.

The ghostly sodium spirit.

The result looks pretty cool, it's almost getting towards my desired streetlight with christmas lights aesthetic.

The mass of the lampshade and streetlight together is a little greater than expected... As a result the pipe bends a lot more than I would like. 

You may be able to see the bend in the pipe here.

So the use of Plan B is necessary: The pipe will now be cantilevered from the first floor  "balcony" with a top stay to prevent the pipe from drooping. Stay Tuned...