Bad arithmetic.
Balls. Do they shrink or do they wear?
- Thread starter Sloppy Pockets
- Start date
Hey Wedge, thats from have to much testosterone in there, you have to let some out, some how r another!
My mistake, one-hundredth, not one-thousandth. But the measurements were consistent in all respects. My calipers that go beyond one inch go to the hundredth of an inch unless you've got very good eyes, to see between those segments.
I don't think the circumference difference matters or else the rules would not permit variation from the standard specs for weight and diameter of the balls. I really doubt you could get a set of matched pool balls all weighing the identical weight down to 1/10ths or even 1/1000ths of an inch. And if you could, it would cost a fortune and probably not amount much of a difference.......the Brunswick Centennial balls all weigh the same with a variance of <.3 grams difference of each other. Do you need a set of pool balls with closer identical weights than the Centennial set?
Remember the rules allow for variation and specify that all the balls be composed of cast phenolic resin plastic and measure 2.25" (15.715 cm) in diameter with a variation of not more than .005" or .127 cm. The weight shall be 5.5 ozs to 6.0 ozs (156 to 176 grams) and for tournament play, the balls should be unpolished and should not be waxed.
So any set of pool balls that weighed the same could weigh 156 grams, 157, 158. 159, 160, 163, 168 etc. up to 176 grams maximum weight. I submit the Brunswick Centennial set is dialed in on weight as close as any you'll find which is really all you want. And the Measles cue ball is the closest in weight to the Centennial balls other than any cue ball but the Centennial Cue Ball which is the same weight as the other balls in the set.
Now try playing with a cue ball weighing 1/2 ounce heavier than the object balls, or worse, have a set of object balls that vary by more than 1/3 and up to 1/2 of ounce, and play using the lighter weight red dot cue ball or any cue ball that's 12-13 grams lighter than the object balls. The see if you don't get inconsistent position with the cue ball or how you do with bank shots or long (8 ft) cut shots separating the cue & object ball, see the difference in cue ball squirt......all this crap comes into play and then there's all the variables that come into play with the cloth.......a lot of variables that need to be quickly evaluated and allowed for or your match could be over sooner than you thought.
Remember the rules allow for variation and specify that all the balls be composed of cast phenolic resin plastic and measure 2.25" (15.715 cm) in diameter with a variation of not more than .005" or .127 cm. The weight shall be 5.5 ozs to 6.0 ozs (156 to 176 grams) and for tournament play, the balls should be unpolished and should not be waxed.
So any set of pool balls that weighed the same could weigh 156 grams, 157, 158. 159, 160, 163, 168 etc. up to 176 grams maximum weight. I submit the Brunswick Centennial set is dialed in on weight as close as any you'll find which is really all you want. And the Measles cue ball is the closest in weight to the Centennial balls other than any cue ball but the Centennial Cue Ball which is the same weight as the other balls in the set.
Now try playing with a cue ball weighing 1/2 ounce heavier than the object balls, or worse, have a set of object balls that vary by more than 1/3 and up to 1/2 of ounce, and play using the lighter weight red dot cue ball or any cue ball that's 12-13 grams lighter than the object balls. The see if you don't get inconsistent position with the cue ball or how you do with bank shots or long (8 ft) cut shots separating the cue & object ball, see the difference in cue ball squirt......all this crap comes into play and then there's all the variables that come into play with the cloth.......a lot of variables that need to be quickly evaluated and allowed for or your match could be over sooner than you thought.
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I agree, but think this is cosmetic rather than the reason for shrinkage. Friction / Heat generated from the bashing of the balls may be the direct cause to shrinkage...
Can a rep from Aramith step forward? :thumbup:
It could also be your caliper, as with any measuring devices error has a way of creeping in so maybe it needs to be re-calibrated.
Thread title ??
If people are curious about the different effects caused by CB and OB weight and size differences, see the online video and articles on the ball weight and size effects resource page.
Enjoy,
Dave
Enjoy,
Dave
Dave... can you please stick to the original post.
I've seen all that stuff several times, and it is very interesting and makes perfect sense, but that's not what I'm asking with this thread. I'm more interested in your scientific opinion regarding phenolic balls shrinking over time. If you don't know the answer, perhaps a colleague does? I personally find it hard to believe that Aramith made their top-of-the line ball .010" too small as it left the factory.
As I said earlier, my brand new (right out of the blister pack) measles ball still measures 2.250" +/- about 5 tenths or so everywhere on the ball I measure it, even after six months of steady use. It's about as near a perfect sphere as I imagine anybody could make a resin ball. Seems like it's not just a fluke it came out that way (although I certainly am interested in reading what others measure their measles balls to be).
Maybe Aramith didn't have the same finishing technology back 20 years ago as they have today, but ten thousandths of an inch is a pretty big difference. I fail to see how sloppy factory polishing could erode the balls that much without severely compromising their sphericity.
It could be for some folks, but that's not the case here.
A dial caliper is a simple mechanical device that relies on a rack and pinion to drive the rotations of the dial. If the thumb wheel turns smoothly and the dial zeroes when you close it all the way, you are good to go. It is quite easy to see a .001" gap between the jaws with the naked eye, so if there is no light coming through when close them and you hold it up to a light bulb, and the dial reads zero, there is no need to calibrate anything. If you see light when the jaws are closed, there is either debris on the faces or there is a burr on a jaw itself preventing them from closing all the way. In either case you must remedy the problem. If the dial is still a bit off at that point (just a thousandth or two), all you have to do is loosen the screw that holds the bezel and rotate the bezel until the indicator needle is exactly on zero and then tighten it again. It will now read true throughout its range.
If it feels rough when you turn the thumb wheel, there is debris between the rack and the pinion gear, and the gear will skip on the rack if you force it. You will know this happened because when you close the jaws again the dial will not read zero, but will most likely read about 1/4 turn of the dial off in one direction or the other. My Starrett is a major PITA to take apart and reset the pinion gear in the right place, so I clean it right away if it's not turning smoothly.
Bottom line is, I won't even take a rough measurement with my calipers unless they are working perfectly and are well calibrated. At that point, I can trust both the instrument and the guy wielding it.
Of course, you have to be very familiar with your equipment. Experts in metrology will be the first to tell you that a measurement is only as good as the guy taking it, regardless of the accuracy of the tool. Just like playing pool, accurate measurement takes thought and a lot of feel, coupled with experience. It is very easy to be way off when measuring a sphere if you aren't already reasonably skilled in measuring stuff.
I thought some people in this thread might be interested on the effects ball size and weight differences can have during actual play. Some people find measurements and data interesting, but most people want to know what happens at the table and why.Dave... can you please stick to the original post.
I serious doubt this can happen because phenolic is very stable.
... unless somebody made a big mistake.
Regards,
Dave
How stable is "very"? Can you put a number on it?
As to making a big mistake, they must have made 16 identical big mistakes and put them all in the same box together with each other. What are the odds of that happening, I wonder?
I can't put a number on it, but I'll ask one of the materials guys in my department on campus the next time I see one of them.
The "big mistake" would have to be something like not applying the finish correctly or not setting the polisher to the right setting or something like that. It would affect all balls in the same batch the same way. Again, I doubt this, but it is possible.As to making a big mistake, they must have made 16 identical big mistakes and put them all in the same box together with each other. What are the odds of that happening, I wonder?
Regards,
Dave
It's going to be a pretty hard thing to do since we don't know the exact composition of the resin. Who knows what fillers they used? They likely all have different stability profiles.
Best I could come up with is up to .01"/inch during curing, which would explain a lot except for the fact that they had to have started with cured resin. To be sure, we would need to have time-accelerated data, and that would be hard to do since they would be mimicking kind of "neutral" conditions (inside a box, outside of direct light, not subjected to extremes of temperature, etc). Still, I'm very interested in what they have to say.
Sure, that could always occur, but what would it say about the quality control of an established European company who had just been awarded a major contract from the largest billiards product supplier in the world? Who knows? Maybe they told Brunswick and Brunswick said, "Look... we'll take them all if you give us half off. Nobody will ever notice a few thousandths of an inch." Wouldn't put it past them.
Anyway, I don't want to start a row with the esteemed scientists here, but my mentor always stressed to me, "Above all, never throw the baby out with the bath water." So I try to think of all the possibilities, not just the likely ones. All I can say is something seems a bit rotten in Denmark.
Or should I say... Belgium.:wink:
FYI, I just talked to a materials expert in my department on campus, and he said there is no reasonable explanation to explain shrinking of resin-based pool balls other than wear and/or excessive polishing. Phenolic resins are thermoset materials and are extremely stable (once cooled and set), even if exposed to harsh conditions (temperature, light, liquids, etc.). If the shrunken balls in question have never been used or polished after they were sold, they must have been sold that way (in their shrunken state).How stable is "very"? Can you put a number on it?
As to making a big mistake, they must have made 16 identical big mistakes and put them all in the same box together with each other. What are the odds of that happening, I wonder?
Regards,
Dave
Thanks for looking into it, Dave.:smile:
It's funny that Saluc would put out a ball set that was .005" under the BCA minimum acceptable size, even on accident. They are, after all, makers of precision balls for industrial use. I guess back then they figured if they rolled true that was all that was required.
The other interesting thing about all this is that they weigh about a gram heavier than slightly larger balls of the same material. They should be about 2 grams lighter instead.
BTW I found the original patent for hardening phenolic resin for billiard balls that was awarded to Harold Luth back in 1946. Interesting stuff to read. Thanks go out to our good friends at the Chicago Billiard Museum.
http://www.chicagobilliardmuseum.org/files/1946_METHOD_OF_HARDENING_CAST_PHENOLI.pdf
I'm kinda bummed that my beautiful Centennials are slightly undersized. I mean, they roll fine, rebound normally off each other, and look great, but you know how this stuff gets into your head. You're shooting great, haven't missed a ball for the last hour, and suddenly you think, "H-mmm... Am I really shooting that good?... or is it because the GD balls are .010" undersize?"
Physics are weird with that kind of stuff. seems about everything changes over time to some degree, even the weights stored in temperature controlled atmosphere in europe that they base their unit weights on have slightly changed over the years when weighed in. theres always theories as to why, but they dont actually "know" why
Title like this confuse me sometimes. 