UPDATE: Read step 7, It shows a better build method and has a link to an Ible that shows how to make the jig.
I also posted and Ible on how to join ball bearings with soft solder here.
I discovered this fun little toy while surfing around the net in the wee small hours last night on a site called www.grand-illusions.com
Hurricane balls are just 2 ball bearings joined together, when spun on a flat surface and then accelerated by blowing a jet of air at them will spin up easily to around 3500 rpm. over 12,000 rpm have been recorded in lab conditions
I was so amazed by this fun little toy that I decided that once I had managed to get some sleep that I would try and build a set of these.
Its a fun little project that is so much fun to play with. Sadly my camera is not high enough spec to really show this thing of, I will try and get a high def video posted asap.
This is quite a simple build but need to be built well as they can reach over 3000rpm if you really blow hard and this provides the potential for mayhem if the balls decide to separate at this speed.
2 matching ball bearings about 12 - 15mm diameter.
1 3mm machine screw.
1 Biro pen, makes a great blow pipe.
A concave mirror to run it on, a flat surface will do but it will work better on a concave surface.
Superglue, this is optional but is a good idea to help lock the threads in place.
2.5mm drill bit.
3mm tap and tap wrench.
2 pair of pliers
Junior hack saw.
Small flat needle file.
The retail version of these are welded together with about 8000amps of current, I did not 8000 amps available and it sounded a bit dangerous to boot so I decided to go with with what I had at hand and went down the bolt it together road.
I have since noticed that there is another Ible for hurricane balls using epoxy to glue the balls together. I just dont have faith in epoxy on metal to metal (or any non-porous surface) when high rpm and centrifugal forces are at play, there is the possibility of a high speed detachment. while your face is a few inches from the source of mayhem. The contact area between the 2 balls is just to small to trust the bond the epoxy would have.
Have fun, play safe and I hope you liked this Instructable.