I needed a simple way to tighten the heavy duty camera arm and double wing nuts worked really well. Effectively I have a piece of M4 stud between two wing nuts. One end will be locked with thread lock.
These are M4 domed caphead bolts from BoltBase. Must admit that I find this company has good parts, prices and deliveries fast.
For the fixed joints such as where the plates bolt to the swivel pin I have used the M4 capheads without washers. These have been tightened with M4 nyloc nuts.
For all of the points where I wanted a moving joint I used caphead bolts and nyloc nuts. I just snug these so they can still move. This is where the nyloc nuts work well as they keep this tightness over time.
However, the holes might need sleeving as a thread will gradually wear the aluminium. A brass sleeve could work.
Even at the head of the heavy duty camera arm I’ve used the M4 capheads and nyloc nuts. The up and down motion of the camera mounting pin is controlled with the split pin. At the moment this doesn’t look that elegant. Maybe a turned knob on the end of the split pin would improve this?
With all of the joints now held snug with the M4 caphead bolts and nyloc nuts the arm is very stable. It is also very fast to move it’s position by releasing the double wing nuts.