Approved Croquet Balls - Specification
1 New Balls
The Equipment Committee administers a scheme for the certification of balls
which are suitable for use in major championships and tournaments. The regulations
are set out in Section 1.2. The World Croquet Federation Management Committee
has recognised the CA's Championship Approval scheme ('International Ball Standard')
and agreed that it applies to all versions of croquet.
Approved Balls
Balls that have current Championship Approval are as follows:
- Barlow GT Mark II 1st Colours (Approved to July 2006*)
- Barlow GT Mark II 2nd Colours (Approved to July 2006*)
- Dawson 2000 International 1st Colours (Approved to November 2010)
- Dawson 2000 International 2nd Colours (Approved to November 2010)
- Sunshiny (CB16) 1st Colours (Approved to November 2010)
- Sunshiny (CB16) 2nd Colours (Approved to October 2008)
- Willhoite Xtreme 1st Colours (Approved to October 2009)
* Approval not renewed: ball production terminated
Suppliers
Recommendations
It is suggested that purchasers may wish to safeguard their rights by ordering
balls that comply with the current CA Championship Specification. Makers produce
balls in batches and the CA is not able to test each batch, so close inspection of
new purchases is recommended. Modern plastic balls appear to be produced from moulds
comprising two hemispheres: it is a simple matter to check that the two hemispheres
have been correctly aligned - any significant step across the joint line causes out
of line rebounds and is unacceptable in play.
Manufacturers who wish to obtain or renew Championship Approval for balls are
required to submit a set (non-returnable) to Equipment Committee accompanied by a
fee of £50 (payable to The Croquet Association). In the event of the balls
failing to meet the required specification, £20 will be returned; balls that
meet the specification will be awarded Championship Approval valid for a period of
three years. Test Reports will be sent promptly to the Manufacturer and those for
Approved balls will be forwarded to the WCF and may be published by the CA.
2 Championship Ball Specification
(Imperial measurements are definitive; metric equivalents are given for convenience.)
(a) Diameter
- The maximum diameter of a ball must not exceed 3 21/32
inches (92.9 mm) and the minimum diameter must not be less than 3 19/32
inches (91.3 mm).
- The maximum and minimum diameters of a ball must not differ by more than
1/32 inch (0.8 mm).
- The maximum and minimum diameters of balls in a set must not differ by more
than 3/64 inch (1.2 mm).
(b) Resilience
- When dropped from a height of 60 inches (1524 mm) from the bottom of the
ball onto a steel plate 1 inch (25.4 mm) thick and set rigidly in concrete, a
ball must rebound to a height from the bottom of the ball of not less than 31
inches (787 mm) and not more than 37 inches (940 mm).
- The rebound height is the average of eighteen measurements: each ball is
dropped three times onto each of the two poles and four nodes in the milling
pattern.
- The rebound heights of a set of balls to be used together must not differ
by more than 2 inches (50.8 mm).
(c) Milling
- All balls must be milled with an identical pattern.
- The pattern must consist of two orthogonal sets of grooves and the width
of the grooves must be less than the width of the upstands left after grooving.
(d) Weight
- The weight of balls must be within the range 15 3/4
ounces (446.5 g) to 16 1/4 ounces (460.7 g).
3 Ageing of Balls
The Equipment Committee is not aware of any definitive assessment of the effects
of ageing and use on the rebound characteristics of Championship Approved balls.
Ideally, sets of balls should be tested when new and at annual intervals thereafter,
but in clubs with several similar sets of balls it is likely to be difficult
to keep track of a particular set. To facilitate such performance monitoring,
Equipment Committee would welcome the assistance of one-court clubs which are
intending to purchase one or two (e.g. 1st and 2nd colours) sets of Sunshiny
balls. Finance would be made available to cover costs and to provide some recognition
for the effort involved. Dawson 2000 International Balls had unchanged resilience
after 2 years use.
Modern cast polyurethane balls may retain a satisfactory appearance even when
performance in the resilience test has deteriorated. It is also noteworthy that
relatively small blemishes on the ball surface have been observed to affect
the direction of rebound in the bounce test. Regular inspection and monitoring
of performance is recommended.
4 Colour of Balls
Colours of first and second colour sets of balls with Approval in 2005 have
been measured and assessed for visibility and distinguishability. Recommended
ranges have been forwarded to makers and a copy of the definitive document is
archived in the CA Office.
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