I’m not entirely sure if this has been posted before, but I couldn’t find anything after a quick search.
If you have a chain-bar design for your arm system, one of your biggest problems is most likely going to be “play” or “slop” in the chain which allows the intake and tray to rotate backwards and forwards. A good way to eliminate this “slop” almost completely is to use zip-ties. My team uses large zip-ties and just replaces two or three links with one large zip tie on the bottom and the top of the chain, and this eliminates “slop” almost entirely because the zip-ties can be cinched very tightly. This works because the chain on the chain bar does not rotate entirely around the sprockets and therefore does not have to have links all the way around, just on the places where it touches the sprockets. I hope this helps! 
