There is a lot of people who do not seem to understand what I do.
This is a good article that explains the process and all the steps involved in engraving of a chromed item.
Some things can be engraved through the chrome, but most plating will peel or chip.
Parts must be removed from the bike or car/truck to be engraved. They can not be done properly in place.
This does not apply to all glass work as it can be done in place.
Hoping this helps to understand the Art Of Engraving.