[AdamHeard]

In the simplified case you present, yes it would be safe. Missallignment or other factors will reduce the load.

I'll say something a lot of people overlook on arms is shafts/bearings. We did 1/2" with FR8 bearings in 2011 and it worked, but in hindsight we wanted something more rigid.

In 2013 and 2014 we used 1" 1/8" wall tube turned to 25mm (barely any material removal as 1" is 25.4mm), and 25x37x7mm bearings. This is a 6805 bearing from the 6800 series and can be purchased for very cheap. We use USA bearings and belts. We used two bearings in each bearing block (as they are so thin), for 4 total. Our two bearing blocks were ~12" apart in 2013, and 18" in 2014.

We turned the shaft to 7/8" diam for long lengths that weren't interacting with anything.

We were VERY happy with the strength and stiffness of it during both seasons.

Both years we drove the arm with a 120T, 10DP 3/4" wide 6061 gear (waterjetted tooth bolted into a hub). We'd likely go a tad beefier for games with more arm to arm interaction, but this certainly was pretty robust for the last two years.

We also used an E6 2500 count encoder from US Digital both years directly on the shaft, our sensor had zero backlash because of this.