Boolean modifier difference not engraving correctly I am trying to make some custom chess pieces.

I am just trying to engrave some images onto the chess piece but when I use the boolean difference modifier, the piece goes crazy and doesn't really engrave it properly.

It seems to cut out faces weirdly and I also have to align the pieces up a certain way, or it won't even apply the modifier at all.

I am trying to figure out how to attach the blend file, but I can't find the button.

Any help with this would be great please!! Complete blender newbie here :(
You have some problems because you need to clean up a bit your meshes:


Select your symbol object, go in Edit mode, select all and W > Remove Doubles.
Also press X > Limited Dissolve.
Select your cylinder, go in Edit mode, select all and W > Remove Doubles.
Give your cylinder a Boolean modifier, choose Operation > Difference, and select your symbol as Object.
It works (well, it will need a bit of topology work)