here is one I media blasted for a nice satin finish, doesnt really scratch easy and easier to hold with wet or slippery hands. this is my beater and had it for over a year now.
here is one I got off the classies cheap it is currently heading toward a brushed SS finish when i have time (more like when i finally quit being lazy)
you have to take something like a long screwdriver and carefully insert it into the body till it reaches the head and tap it with a hammer. moving the screw driver to a couple different places. slowly you will see the head start to come out when it does you have to go slow as the board is wired to the head. once out the button will just fall out of the hole, then unscrew the window and ready to do what you want.
reassembly is easy as well, put the window back in, drop the button in the hole, slide the board back in to place (there is grooves on the inside of the tube) add a few drops of hot glue to the top edge of the board (to keep it from moving around after assembly) set it on the table and take a hammer or something solid and tap the head back it.
As you can see there really isnt anything to damage on the underside of the head as it is just a solid almost 1/2 in thick chunk of stainless,
the only thing to watch out for is making sure you dont scrape the rod,screwdriver, whatever across the curcuit board when you stick it in.