So some of my parts need to have fairly close tolerances in order to maintain precise spacing in the finished joints. I hope that the 2:1 ratio between the pins and the actual lateral movement of the sled will reduce some of the error or slop in the arm, but after running an preliminary test in 1/2" acrylic I can tell that laser cutting the inner bearing slot in the arm is not going to be sufficient because as the laser cuts deeper, even with refocusing after each pass, I'm still getting a slightly V-shaped slot where the sidewalls angle in towards the bottom of the cut. I'll definitely need to mill this piece if I want greater accuracy. Now I'm not sure if I shoudn't upgrade at least the arm to Aluminium instead of Acrylic.