"Scissoring" Monitor Mount - Cantilever Tipping Point

[zild1221]

OK. Hopefully you guys can help me. I could do this off of just trial and error, but I would rather not have to re-cut any of my material as it is expensive. I just built a nice new desk and would rather not permanently mount a scissoring monitor mount. I have triple 24" monitors. My old setup was that the center one was permanently affixed, and the left and right were attached to two articulating arms.

My new setup, I want to be able to pull all 3 monitors close to me, or push further away without having to slide something across my desk. I have Misumi aluminum extrusion coming out of my ears, so I figured I would build a "scissor lift" type design that is mounted horizontally. I am not worried about flex in the extrusion or anything like that so hopefully this is easy.

I need to figure out how long of "legs/feet" I would need out forward of the main upright of the mount. Here's a really rough diagram of what I mean. The red bits are the legs. Forgive the rough'ness, I'm on a crappy old laptop and can barely run sketchup!

http://i.imgur.com/g9gq2ns.png

I'd like the monitors to come forward 16" or more possibly. Each monitor weighs about 9lb, the two articulating arms I have are 2.2lb each, and between the aluminum that extends off the uprights and the panel that the middle monitor mounts to, I'd figure maybe another 3lb on the high side.

If you guys could provide any insight, I would greatly appreciate it. Thanks.

 

[elegysix]

I need to figure out how long of "legs/feet" I would need out forward of the main upright of the mount. Here's a really rough diagram of what I mean. The red bits are the legs. Forgive the rough'ness, I'm on a crappy old laptop and can barely run sketchup!

This will depend on how heavy the base is. The safe bet is just to make the feet come out as far as the monitors do. This will guarantee it won't tip on its own.