So I learned a lesson on set yesterday. There is topside and a bottom side of an arm post. I apparently had mine upside down and it snapped. Luckily it was a light setup, Sony F800, and I was able to hold onto the sled. Only the arm post and a ¼ 20” cold shoe from my bolt transmitter were damaged. I have a 10” arm post too so I was back up and shooting within 5 min.
The top of the 6” post has a hole right at the top. The bottom has a hole 15/16” of an inch from the bottom. Glad I know now.