So like most pinheads I have a bunch of old pinballs laying around. I just bought a batch of new regular balls, I used to buy the premium shiny ones but I had issues with magnetism in some games so I went back to the regular ones. Anyway, this got me thinking about whether or not it was practical to polish pinballs?

So just to caveat this, I am not saying this a good idea or something people "should" do, I was just curious and put something together this afternoon with stuff I had around the house and thought I would share the results.

So I did a little research and found this youtube video and these professionals use these cups with abrasives to cut and polish spheres. But in one shot I also saw they use cups with just leather on them, which was something I had some scraps of.

Screenshot 2022-11-08 162213 (resized).png

I also saw this guys who polishes stones and he uses primarily a three cup setup but also mentions an 2 cup system. It seems the trick is getting the ball to roll randomly in the cups.

Screenshot 2022-11-08 162919 (resized).png

So I thought I might be able to try something quick at home. I went to Home Depot and got some very simple hardware. Just some 3/4" PVC pipe and some 5/16" nuts/bolts.

IMG_20221108_142007789 (resized).jpg

I then glued in the PVC plugs and drilled them out to 5/16 for the bolt. Then I cut out the leather in a circle and cut some gaps for the folds and then used a pipe clamp to the PVC fitting.

IMG_20221108_150850044 (resized).jpg

IMG_20221108_150111013 (resized).jpg

IMG_20221108_150607805 (resized).jpg

IMG_20221108_161922141 (resized).jpg

So my basic idea was to set something up in my small drill press. The simplest was to have the upper moving and simply fix the lower. I thought that if I put the bottom at a slight angle it might move randomly. I put the "white" metal polishing rouge on the leather before I started.

IMG_20221108_153736968 (resized).jpg

It didn't really seem to be moving randomly so I then used my right angle drill strapped to the drill press and tried that:

IMG_20221108_154957728 (resized).jpg

So it did work but it gets hot and I was periodically spraying with water to keep cool. I tried it for ten minutes and you can see the before and after:

IMG_20221108_160148003 (resized).jpg

IMG_20221108_161425044 (resized).jpg

I also measured the diameter as best I could and the before was 1.062 and the after was 1.061 which was actually more than I expected but it is just a cheap caliper so it might not be accurate. I couldn't find any out-of-round but again I am not 100% sure of the measurement.

I think if I was do do something more serious I would make a two drill (plug in) setup over a tub so I could drip water on it. I am a little concerned that the amount you would need to polish to get a seriously mirror finish might take off more material than would be good to use in a pinball game. .001" is not very much but at some point it would effect the game.

Anyway, I thought it was an interesting experiment so I thought I would share.

In that first try I was using old balls but out of curiosity I took a brand new basic ball and a new Silverjet (both from Marco). I was wondering if I could polish the basic one up to the Silverjet. The reason for this is that the Silverjets have issues with magnetism so you might want the shinier version but without the magnetism.

So I ran a basic ball for about 10 minutes and it polished up to the Silverjet. Unfortunately it is way more obvious in person than in pictures. So here they are fresh out of the package:

IMG_20221108_175515195 (resized).jpg

Again, it is obvious in person that the one basic one is rougher than the Silverjet.

Here it is after polishing with another not polished one above it.

IMG_20221108_181207852 (resized).jpg

So it does work. I will admit that I did this mainly because I was curious if I could. I am aware that after any decent amount of time playing in the game they are likely to lose that high polish but that is true of the Silverjets as well.

I think a rock tumbler might work but I don't have one.

I measured the second set I polished (the new one) and I couldn't find any size difference. I suspect it is smaller than <.001 so they can't be out-of-round very much.

That's interesting, he says to use a buffing wheel but they are hard to hold on to. I can't tell you how many times I have tried polish something small only to fling it across the shop.

I like your set up a lot. Modified mine similar to your's. I removed the leather and just sat the ball in the PVC. If the PVC was stationary then I was not getting random motion. I learned you can mark it with a sharpie when it is working and you can see if the marks move. So I used the drill on the bottom as well. However, it worked great. I was way easier to apply the rouge and the ball didn't get hot. This meant I could walk away and let it run for ten minutes.

IMG_20221109_093333746 (resized).jpg

After ten minutes the balls came out pretty much perfectly polished. I can't see any scratches at all on a new standard ball. I am guessing a "grey" used ball will still have scratches but I will check later today. While I have it set up I am going to polish the 10 standard balls I have on hand. Thanks for the suggestion.

IMG_20221109_095003260 (resized).jpg

Honestly, it works great. I have found that 20 minutes will bring back most used balls. I am a little obsessive and have been polishing all my old balls. I am now sorting them by "grade". I may never need to buy new pinball again!

IMG_20221110_211846487 (resized).jpg

Do you mean a rotary style or a vibratory?

I had a vibratory for old pinball hardware and I really didn't like it for various reasons. Partially because it was a cheap harbor freight one but also because it just didn't need it. I use scotch-brite on larger metal parts and I just replace old hardware. However, I figured that the balls were too heavy and would just fall to the bottom of the vibratory? I thought a rotary one might work.

How polished does it get them? My gut is that the buffer will get them to a higher polish.

One thing I like about my current setup is that it doesn't get the balls hot. The leather got them very hot.