So, I own a hand held XRF gun.
For those of you that don’t know what it is or what it does, let me explain.
It uses X-ray fluorescence and scans the surface metal a certain number of micros deep giving you a reading of what the metallic composition is with percentages including trace elements.
There are various industrial uses for it ranging from scanning soil samples to see what metals they contain to scanning precious metal for composition.

We use this in the office for a variety of application. Mostly scanning things like rare coins for trace elements as a tool in determine authenticity and vetting counterfeits. For instance prior to electrolytic refining many trace elements could not be entirely refined from the ore when it was smelted and assayed. Many silver coins prior to electrolytic refining have 1/4 to 1/2 of a percent of gold and other metals in them because refining techniques at that time were not able to remove 100% of the trace metals from the ore.

Does it have limitations? Yes, absolutely.
Certain items like items that have been plated will not give you a correct reading. Since it only scans so many microns deep, it would give you a skewed percentage and a larger percentage of the plated material would show in a reading rather than the objects actual composition.
For instance I could get a pretty good reading on a pinball, but not one that’s been chrome plated.
It’s not 100% infallible and there is a small margin of error. The only real way to get a correct reading of composition would be to melt an item completely down and test a core sample. You can also get an inaccurate reading if the metal is oxidized or you don’t have a clean surface. Oxidized parts will not read the same as parts without oxidation or corrosion. Essentially trace elements and lesser metals tend to get eaten away first in the corrosion process.

Anyhow, it is an interesting tool and since I have one was wondering if it would be useful for testing the composition of pinballs or perhaps pinball parts?
Maybe there are certain metal parts with a higher failure rate than others, or pinballs that get beat up faster than others?
In these cases it might be interesting to see what their metallic composition is and what they are alloyed with.

Here’s a sample I did where I scanned some pinballs I purchased from Marco.

Fe 99.33% Iron
Mn 0.54% Manganese
Cr 0.05% Chromium
Sb 0.03% Antimony
Pb 0.02% Lead
Sn 0.02% Tin
Zn 0.01% Zinc
Zr 0.00% Zirconium (almost unmeasurable amount)

So what exactly does all this stuff being in the alloy mean? Well, the 0.54% of manganese and high percentage or iron are really the two things you want to focus on in this case. About a half percent of manganese is what’s needed in the process of making steel. The fact that the iron is refined to 99%+ is also a good sign.
The rest of the trace elements that are showing are very minor and insignificant remnants of other metals that probably had a higher concentration prior to refining. It’s way too expensive and costly to get these tiny percentiles out 100%.
In short, this is a well made pinball that is refined and alloyed correctly.

Thinking about testing some other stuff.
Any suggestions?
Other pinballs, lock down bars, coil stop etc?

Anyhow, might not be useful at all, but I thought it was interesting.
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I can probably do something like this with the machines I have.

My two older Sterns are POTC and Big Buck Hunter. Both are home use machines that have not had the coil stops replaced, so they would be fine to do a sample test.

All my newer sterns with the exception of Beatles I am the first owner and none of them have had the coil stops replaced, so I could test those as well.

That said, I haven’t had a coil stop fail on any of those machines. Maybe they are not made in the time period you are referring to, or maybe I just got lucky (don’t know).

If somebody wants to send me a broken one that failed, I would be more than happy to test it.

Thinking about this a little further.
I could probably test a few other manufacturers as well. I have one CGC, a few Spookys and couple JJP pins as well, where I know the coil stops have not been replaced.
Things like my older Bally/Williams games I would be more skeptical about testing, because I have no idea what’s been replaced over the years and whether or not what I would be testing is an original part.

Yes, you need a clean surface to get the most accurate reading. Anything as hearing to the surfaces would contaminate the reading. It’s will scan though paint, but it’s sort of like getting a reading though a filter and can skew the data.

Interesting. Like I said, I haven’t had this issue with any of my Sterns, so haven’t really followed that topic all that closely.
I would still be willing/interested in testing one of the stop that has broken out to see what it’s made out of.

I can do that on the machines that I have that still have the original balls in them.

I scanned the balls that shipped with my Deadpool premium last night. This is a good example of how a plated item gives you a slightly skewed reading. If you notice the percentage of Iron and Manganese are slightly lower, but the Chromium level is higher. That’s because it’s reading it through a fine layer of chrome plating.
I.E. there’s a higher level of chromium on the surface from the plating.
The thicker the plating, the more this will be skewed. In this case the plating is extremely thin. The rest of the percentages all seem correct when you take the plating into account.
I’ll test some others tonight when I get home from the office.
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Shape shouldn’t matter as far as convex or concave as long as you’re getting a full scan of the surface area.
That said, whatever your scanning has to have a large enough surface area to get a good reading. If an item is too small you may be getting a faulty reading as it would be analyzing whatever it’s sitting on or attached to.
You wouldn’t scan something that’s transparent like plastic or glass. It won’t register (unless you had something like leaded glass). We’ve scanned coins though the clear plastic on a slab and it still gives an accurate reading of the coin through plastic.