Self articulating Arm

I really like the Articulating arm by doctriam and the remix by igorF2. But how much cooler would it be if it were to move on its own without untightening and tightening the screws....so here it is!!!

This design uses a spring to push down on the articulating groves and stops allowing for free movement until the next grove is reached. The knob can adjust the amount of force needed to move the arm.

The arm is intended as a general purpose item. Hope to see it used a bunch of projects! However I have include the LED lamp parts by igorF2 since its seems to be popular. Please note that there is only one size of arm included and the overall size is 120% of igorF2 design to accommodate the spring.
You can use a 9/32" or 7/32" spring. check out harbor freight if they have a large box of assorted springs for $3.

Also if you find any thing wrong with this please let me know so i can work on it. Thanks!