Adjustable twist lock tent pole

Adjustable Twist lock cam system for generic Aluminium tube.    Multiple uses but tent pole is basic use case.   Built as commercial twist lock tent poles were a rip off.  Could buy two diameter 6.5m lengths of tube and a roll of filament for the price of one or two poles.   You can buy these twist locks on Ebay etc but they are also very expensive for the tiny piece of plastic they are and only come in one size.  

Example of other use case for this is:- https://www.printables.com/model/232077-fully-adjustable-quickly-removable-low-profile-van

3 current sizes for Al tube extrusion:-

12mm OD x 1.6mm WT 

16mm OD x 1.6mm WT

20mm OD x 1.6mm WT (which fits inside 25mm x 1.6WT)

Insert fits ¼" solid bar

Need to Araldite (or some other glue) the main body into the tube else will rotate when trying to lock the cam.  Works far better than expected.  Larger size easily holds body mass.  8mm x 6mm carbon tube fits inside the 12x8.8mm tube for possible smaller cam but still waiting on order to arrive.

If you want to make your own for different sized tubes the design is just a circle offset by 1mm from center.   You make the larger part as big a diameter as you can to handle the torque.   The cam OD you make exactly the same size as ID of the larger tube so it needs a tiny squeeze to fit.  The tolerance in diameter between the Cam ID and main body is about 1mm but you may need to adjust.  The smaller the tube diameters, the harder to get the tolerance correct.  In Australia you can purchase the Aluminium tube in these sizes at Capral. The smaller sizes don't currently seem to be listed on their website but you can call/turn up to confirm they have stock.