Quoted from High_End_Pins:It’s pretty much the same principle as mounting an air compressor on rubber isolators it’s done to keep the equipment from transferring its energy into the floor.
When a ball hits a post mounted on rubber the post will absorb that energy more than one that is not.
Since pinball post are not supposed to be mounted on rubber it changes how the game plays.
How much or if it even matters would be pretty hard to argue but it can be avoided if it is a concern via the method I just posted.
We are all just trying to figure out solutions to problems we shouldn’t have.
I still disagree. The rubber isolators I am familiar with have a rubber substance with some sort of threaded fastener on either side of the rubber which allow the rubber to float free.
Here is an automotive motor mount with the "rubber" bonded to metal on both sides. The rubber is floating free, allowing the mount to cushion the engine from the vehicle frame and dampening engine vibration from the vehicle frame.
Here is another design with flange mounts on both sides of the rubber isolator with a threaded hole coming in from the other side, allowing two pieces to be attached and still be insulated from each other.
And one more. This style is an inner barrel and outer barrel with rubber in between. When you install the flange plates to the bolts they are isolated from the mounting plate.
IMO, a rubber washer compressed between a post and the play field is not an vibration isolator. When that post is screwed down tight, there is no way the rubber washer can move and no way the post can float free. It is down tight. It is the equivalent of taking this style of isolator
and drilling a hole all the way through the center, installing whatever attaches to this center hole and running a bolt all the way though and tightening down. Do this and you have lost most, if not all, isolating properties of the rubber mount.
This is how I see it.
I'm not knocking the use of the solid washer that you employ. I just prefer the rubberized washers. Trust me. They are down tight and there is no movement of the post.