Thick wall "rubber" hose makes a pretty good vibration absorbing bobbin when forced into a reasonably thick substrate. Make the hole a touch undersize so the rubber is a tight fit. Cut the rubber overlong so it squidges out to make a flexible rim when things are tightened down. Through bolt needs to be a tight fit with large stout washers between it and the rubber so things squidge nicely. Best to use nylock or similar locking nuts so the squidge can be adjusted to tune things for best performance.
Generally I reckon 1/4" overlength each side works well enough with 3/4" to 1" thick substrates using my stash of thick wall car heater hose.
Similar technique without the squidge works well for stiff, shake free, pivots and hinges on things that only move occasionally.
Clive