Is there a reason that the finisher movement needs to be in a predominantly vertical direction. All of the spring based ones are being shaken up and down is there a reason why a horizontal linear shaking wouldn't work? It would be much simpler to build. Would it be that it would take longer? I am wanting to build a finisher for steel motorcycle frames that I chrome plate. I talked with a local company about having them plate them and they mentioned they have a polishing machine and it takes about 4 hours. I dont mind if mine takes 40 hours if it can be done reasonably cheaply and can leave me with just needing to color buff.

We have three vibratory machines in our shop that are run on an almost daily basis. Since you mention springs, I assume you are talking about the standard vibratory finisher with a torroidal bowl, rather than a tumbler, whiich doesnt generally have prominant springs. The bowl on a vibratory finisher isnt reallt moving uo and down. The springs are there around the bowl circumference to enable it to shake. What then happens, because the bowl is a torroid, not simply a round bowl, is the finishing media and parts go around in a circle that is continually folding in on itself, generally from the outside of the bowl towards the inside. This gives an almost continuous abrasive action which makes for shoter cycle times than using a tumbler. In a tumbler the abrasive action only occures at descreet intervals, when the part/media mix has rotated up the wall of the container and slides back down.