Ball size testing

Bavafongoul said:
Well, hopefully you already started to eliminate and replace mismatched sets.
I know it took Tommy five to six months to swap balls and sets at his pool hall.
I carry calipers & scale in auto’s trunk but these can slip in my Aramith ball case.
For only $12 bucks, it costs about a cube & a half of fancy chalk & doesn’t wear out.
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Interesting, I have been having an issue getting all balls to touch on 8 ball racks even with a template. This seems pretty cheap to confirm. I have two sets of aramiths I can test. Would be interested to see the tolerance deviation difference between aramiths and a company like dynasphere.
 
Update on the laser cut gauge. I found a way to measure them with better accuracy than inside jaw dial calipers. I bought an inside micrometer from ebay for about $15. Its an old Brown and Sharpe. I wanted another type of inside micrometer with two pins, but could not find in the size range for a pool ball. The laser cut gauge is right on, better than .0005". measured at a few points around the circumference.

The high accuracy 2.250" steel ball bearing does not pass through the 2.250" gauge, as expected. I will order another set probably from 2.240" to 2.253", in .001" increments, and see how they do. I'm making an order for my day job in a couple of days, and I'll sneak these in.

.040" thick aluminum was the winner on the material. It looks good, stiff enough, and cheap.

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iusedtoberich said:
Update on the laser cut gauge. I found a way to measure them with better accuracy than inside jaw dial calipers. I bought an inside micrometer from ebay for about $15. Its an old Brown and Sharpe. I wanted another type of inside micrometer with two pins, but could not find in the size range for a pool ball. The laser cut gauge is right on, better than .0005". measured at a few points around the circumference.

The high accuracy 2.250" steel ball bearing does not pass through the 2.250" gauge, as expected. I will order another set probably from 2.240" to 2.253", in .001" increments, and see how they do. I'm making an order for my day job in a couple of days, and I'll sneak these in.

.040" thick aluminum was the winner on the material. It looks good, stiff enough, and cheap.

View attachment 645917View attachment 645918
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How did you calibrate the eBay inside micrometer?
 
kling&allen said:
How did you calibrate the eBay inside micrometer?
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A 2-3 Starrett micrometer, that was calibrated to a new 2” Starrett micrometer standard. It actually was right on when I bought it so I didn’t move the zero.

The tricky part is the faces are convex, and the sheetmetal is thin. That’s why I wanted the other type with the pins. But I was able to get it to work in the end.

Of course 2 points of contact can’t measure roundness errors. But I think it’s good enough.
 
iusedtoberich said:
... The high accuracy 2.250" steel ball bearing does not pass through the 2.250" gauge, as expected. I will order another set probably from 2.240" to 2.253", in .001" increments, and see how they do. I'm making an order for my day job in a couple of days, and I'll sneak these in.
...
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Or, you could cool the ball bearing a known amount in a water bath and from the CTE you could calculate the size reduction. I'm guessing that would be plenty to get it through an "equal sized" hole.
 
Bob Jewett said:
Or, you could cool the ball bearing a known amount in a water bath and from the CTE you could calculate the size reduction. I'm guessing that would be plenty to get it through an "equal sized" hole.
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At first I thought you were making an aiming joke. Ha ha.

Let me put my hands on the gauge a while to see if that’s enough.
 
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