Pinballs, Mirror, Premium and One Microinch Finishes
I like smooth, shiny pinballs because I believe that they play better and reduce playfield wear. I also prefer chromium steel balls, because they take longer to beat up. Old pinballs are like sandpaper.
Here's a reference guide to help you know what kind of pinballs you are getting. You can look at your pinballs under a strong magnifier and see the difference.
Pinballs are just 1-1/16" ball bearings. The manufacturer makes steel balls of the right size, then runs them through a polishing process to make them shiny. The balls vary in both size and surface roughness.
Typical pinballs use an inexpensive finishing process that leaves a fairly rough finish. you can easily see the roughness with a magnifier. The next step up is to polish these pinballs, to make them look shinier. The process works: these polished pinballs have a brighter appearance to the eye, but still have a visibly rough surface.
The third option is to extend the manufacturing process, and take the surface down to a smooth, shiny finish.
So I acquired some pinballs from various suppliers to see what I might get.
It turns out that photographing pinballs is pretty tricky. They really want to reflect the world around them. So I used two approaches. First, I photographed the balls in a group. Here, you can see that the blurring in the image is due to the surface of the ball, and not a difference in focus. Then, I took individual pictures using a constant setup and a F/11 aperture to maximize depth of field.
I washed each pinball in soap and hot water, then dried them off with a paper towel. I didn't touch them with my fingers as I wanted to avoid fingerprints and other marks. The Mirror Glaze pinball came out of the bag and had a quick wipe. There's some evidence of light oil remaining.
First, a regular carbon steel pinball; a polished carbon steel pinball, and a 1 microinch finish chromium steel pinball (left to right).
I had, sitting in a box, a few of the original "Mirror Glazed" pinballs. The vendor's marketing tactics drew a lot of criticism. But the surface finish is visibly superior to the regular and polished balls.
A polished carbon steel pinball; a 1 microinch chromium steel pinball; and an original "mirror glaze" pinball (left to right).
|Now, a 1 microinch polished chromium steel ball. The surface of this ball is near perfect.||Closeup of the reflection of the lamp in the chromium steel ball. Looks like a mirror|
|Here's the "Mirror Glazed" ball. It looks as good as the 1 microinch ball, until you get to the last details. Then, the ball shows very, very fine scratches in the surface.||Fine surface irregularities in the original "Mirror Glazed" pinball.|
|A regular steel pinball. Note the rough surface appearance.||Relatively rough surface of standard pinball.|
|A similar ball, polished to a high shine. The rough surface remains, but the higher points are polished so the ball looks brighter.||Polished version of a standard pinball.|
Finally, a note on materials.
Pinballs come in two varieties. Regular carbon steel, and chromium steel. Carbon steel is surface hardened only, and is a bit softer than chromium steel. Because the interior is relatively soft, carbon steel doesn't hold magnetism. Chromium steel is harder than carbon steel, but the ball is hardened all the way through. This means that the ball can hold sufficient residual magnetism to be a problem with a dimpled ball trough.
There's no reason that a carbon steel ball cannot be polished to the same level.