size of balls

[C-J]

What size balls do the pro's play with?Is it 2 inch(51mm) or 2 1/16 inch(52,4mm)?

[The Statman]

The rules used to state 2 1/16 inches but the rulebook is now metric with a diameter stated as 52.5mm – with a tolerance of ½mm so the old imperial balls are still ok.

Definitely not 2" exactly, though.

[Son of Cliff]

2 1/16 inches for snooker, 2 inch balls are used on 8 ball pool tables with a 1 7/8 inch white, and 2 1/4 inch balls are used for american 9 ball tables.

[moglet]

I believe the tolerance is actually +/- 0.05mm

[C-J]

I ask because i ordered a set of balls for my quartersize table.They seemed a bit big to me and then i noticed that the white was a little bit smaller,so i measered them.The white was 51mm and the others where 52.4mm.The strange thing is that the white seems to be the size we use at my club(haven't checked yet).They are brand new aramith balls in the box,very heavy and good quality.(and a bargain for 10 euro)

[davis_greatest]

I believe the tolerance is actually +/- 0.05mm

That is correct - at least, according to the rules that World Snooker publish on their website*. It says that the balls should be of diameter of 52.5mm with a tolerance of +/- 0.05mm.

In old money, that means balls of fractionally over 2 1/16 inches. The metric units were chosen to be as close as possible to 2 1/16 inches, but expressed to the nearest half millimetre.

The smallest acceptable size would therefore be 52.45mm, which equates to 2 inches + about 1.04-sixteenths of an inch.

So, taking the rules literally, an "old" ball in imperial units of 2 1/16 inches would be just too small, but only by the thickness of a very thick human blonde hair or very fine black hair, so I'm sure no one would mind.


*and it's quite possible that there is a mis-print on the website, as 0.05mm does sound like a very small tolerance indeed...

[moglet]

Touché, d_g, except that half a millimetre is easily discernible if you put the two dissimilar balls side by side.

Now was that male blond hair or female?

[davis_greatest]

Touché, d_g, except that half a millimetre is easily discernible if you put the two dissimilar balls side by side.

Now was that male blond hair or female?

Hard to tell without DNA analysis or smelling it for perfume.

[moglet]

I see, d_g, you have edited your post with the caveat that there may be a misprint.

Everywhere?

Unless I am much mistaken the tolerance is taken direct from Saluc/Aramith as their own tolerance limit. Could I be wrong?

That they do not always adhere to it is another matter.

[davis_greatest]

I see, d_g, you have edited your post with the caveat that there may be a misprint.

Everywhere?

Unless I am much mistaken the tolerance is taken direct from Saluc/Aramith as their own tolerance limit. Could I be wrong?

That they do not always adhere to it is another matter.

I was only wondering if it could be a misprint, partly as The Statman's post had quoted 0.5mm. If 0.05mm is the tolerance given by the ball makers and you have seen that before, I am sure that must be correct.

Thinking about it, it is not that difficult to obtain such a tolerance with modern manufacturing methods. The greater challenge is ensuring such factors as uniform density and composition of the ball, to ensure it responds correctly.

[moglet]

Agreed, but how will we tell, it is easy enough to use a micrometer to measure the average diameter of a ball, it is much more difficult to measure the other factors you mention.