Clocks hate to be moved once they are set up. Setting up a clock often requires that the clock must be adjusted by putting it back in beat, especially if the surface has a different level from the earlier location. "In beat" means that it has a rhythmical, even tone in the tick-tock. You can hear the difference if you take a wall or mantle clock and tilt it from one side to the other until the tone changes. If a clock is way out of beat, it will stop.
If a mantel clock was originally set up to run on a perfectly level shelf (or vertical in the case of a wall clock), then the clock must be similarly positioned in the new location. This can be done either by tilting it one way or the other to make it level like the original location. When a clock leaves the factory or repair shop, I set them to operate on a perfectly level or vertical position. The old trick was to put coins under one side of a mantel clock or tilt the wall clock to the right or left.
But sometimes the clock can be so far out of beat that it stops even if vertically aligned. It may have to be so tilted to have it run rhythmically that the internal mechanism needs adjustment. That's where I can help.
There are other essential set up considerations. For example, grandfather clocks are heavy and have a high center of gravity. It is very easy for them to be knocked over with disastrous results. All such clocks must be anchored to the wall. This is absolutely essential if you have children around of if it is in a high traffic area where it could be bumped. A grandfather clock on a rug is also not as stable as one on solid flooring.
Additional information can be found at Antique Watch & Clock Repair and Restoration
and also on Setting up a mechanical clock: eBay Guides
and specific to grandfather clocks