The sizes of winks

[fluppeteer]

Historically, we've had a supply of winks that everyone has used, so (unlike personalised squidgers) the legal size of winks hasn't mattered too much. However, we're now in negotiations to try to source more winks, so this suddenly matters.

The rules currently state that all winks should be approximately 1.5mm thick, with the smaller winks 16mm in diameter and the larger winks 22mm in diameter. I've historically tried rendering images of winks (for trophies and the like) with winks of this measurement, and they look "wrong" (visibly too thin).

A while back, I measured some winks (at least two sets' worth) and found the following to be a better match:

Small thickness: 1.85mm (measurements were 1.7-2mm) Small diameter: 15.5mm (measurements were 15.4-15.6mm)

Large thickness: 1.65mm (measurements were 1.5-1.8mm) Large diameter: 21.5mm (measurements were 21.5-21.6mm)

Rendering with these sizes looks less "wrong" to me. The following image places the measured sizes on the left and the "official" sizes on the right. I hope I've got the aspect ratio right, otherwise this will be misleading.

(Actual winks are rarely properly toroidal: they tend either to be a bit squashed or to have vertical parts to the edge. But we need to approximate with something.)

I'm concerned that replacing winks with those actually 1.5mm thick might significantly affect the weight and the behaviour as one squops off the curved edges.

Before we get as far as ordering replacements, could the RSC please check the sizes of their winks and see whether we want the rules to reflect reality? If we explicitly decide to aim at 1.5mm and deprecate the old winks as "phat", I don't mind, but I don't want to do it accidentally.

[timhunt]

I think the rules should reflect reality, so I think we should change this.

I have never been aware that large and small winks were different thinkness. Does it work to standardise the thickness as 1.75mm?

Not sure I have anything good enoguh to measure my winks to that accuracy. If I can, I will.

[fluppeteer]

Ooh, tags. Thank you, I forgot.

If we can dither long enough, I could bring my calipers to the London Open so someone can have a really exciting lunch time. (Perhaps Alan could do it while the rest of us play drinking games...)

[timhunt]

This pedantry seemed like a good excuse to buy a micrometer. It seems to reliably measure to the nearest 0.01mm. However, tiddlywinks are definitely not reliable to 0.01mm. They are not even flat. I took to measuring each one in 4 points around the circumference because some are significantly wedge-shaped. Anyway, I have reported the range of thicknesses I measured for each wink in one of my full sets.

Big
B   1.59-1.66   1.69-1.72
G   1.75-1.76   1.59-1.62
R   1.56-1.58   1.57-1.61
Y   1.59-1.62   1.55-1.59

Small
b   1.75-1.77   1.69-1.73   1.76-1.77   1.89-1.92
g   1.77-1.78   1.73-1.81   1.77-1.79   1.85-1.86
r   1.90-1.92   1.90-1.93   1.86-1.87   1.88-1.90
y   1.74-1.78   2.02-2.03   1.89-1.93   1.61-1.64

I still think that, for the new sets, we should aim at the same thickness for large and small, and it still seems to me that 1.75mm is the most sensible number that is consistent with the current winks.

However, accurate maufactrure is clearly very difficult, so I wonder if it is more realistic if the rules just mandate "Between 1.5 mm and 2 mm thick". Remember, there is already Rule 2.5 "Winks, mats and pots approved by National Associations should be used wherever possible."

[fluppeteer]

I, of course, commend your nargery. Although I no longer have the full set of figures to hand, I too detected significant variation across both axes between points on the same wink (some are significantly non-circular as well as not having fixed thickness).

I can vaguely see the merit in small winks being thicker: it makes it marginally less likely that you'll overshoot when squopping (since large winks have a larger area onto which to miss), and it probably makes the weights a bit more even. I suspect it was a happy accident, though.

I'm happy to suggest 1.75mm; that's at least on the lower end of the range of small winks and upper end of large winks, so they may not be completely different from our current sets (I'd quite like us to be able to mix and match if possible). I've mentioned both my measured range and the 1.5mm figure to several prospective manufacturers and asked whether a round 1.5mm would make a difference to price; I'll bring up 1.75mm as well should I hear back. So far my only response is from Sentinel Plastics, who decided they can't help. Fingers crossed for the others.

I'd be happy with "between 1.5 and 2mm thick" in the rules, although I hope we can be a little more precise for manufacture. I have impressed on people that our current winks aren't perfectly consistent. I do think that, unless we manufacture them as such, the rules should stop saying 1.5mm.

[hatj2]

I prefer giving an ideal measurement and a tolerance limit. I would therefore suggest 1.75mm with a tolerance of 0.25mm. What we might like to discover is if there is a noticeable difference between 1.5 and 2mm winks in terms of playing, so that, for example, if one player had only very thick winks and the other only very thin winks we could see whether one had an advantage. I would expect the thicker end to be better to play with. In the laws of croquet there is an appendix of equipment tolerances, which is something I like: https://www.croquet.org.uk/?p=games/association/laws/6th/laws6th#a1 While we say that our equipment is 'approved', in practice this means 'we looked at them when we bought them 30 years ago'; nobody is actually testing the equipment used in tournaments. If we cared more then someone (me?) ought to be going through the sets of winks before each tournament and checking them. In practice this isn't necessary, but who knows what a new batch of winks may bring.

[fluppeteer]

That's not entirely true - we've certainly rejected winks that are oddly bent or scratched, and we've been known to filter out under-sized greens. The problem with a tolerance (and in stating a size range) is that we don't know how closely we can meet it, or if there's a bias away from centre; on the other hand, not specifying does mean that we could find almost all UK winks are closer to their average than some that a third party wants to make.

As with the argument that it's annoying to spend a week making a squidger and then be told it's illegal, I'd like a company to be able to say "I can make some winks for these people" (or for independent sale) without having to tool up first and then have us retrospectively decide whether they did a good enough job.

[hatj2]

Surely, though, it's easier for a company to work to a specification? If we say 'between 1.5 and 2' that's quite vague; if we give them an ideal and a tolerance we're in theory happy with they'll be able to know exactly what they're aiming at and also know what is unacceptable.

[hatj2]

And, of course, if they all turn out to be bang on 1.9, or whatever, we can retrospctively alter it.

[RickTuckerUSA]

The rules currently state that all winks should be approximately 1.5mm thick, with the smaller winks 16mm in diameter and the larger winks 22mm in diameter. I've historically tried rendering images of winks (for trophies and the like) with winks of this measurement, and they look "wrong" (visibly too thin).

A while back, I measured some winks (at least two sets' worth) and found the following to be a better match:

Small thickness: 1.85mm (measurements were 1.7-2mm) Small diameter: 15.5mm (measurements were 15.4-15.6mm)

Large thickness: 1.65mm (measurements were 1.5-1.8mm) Large diameter: 21.5mm (measurements were 21.5-21.6mm)

Note that historically small winks were 5/8" in diameter (15.875 mm) and large winks 7/8" (22.225 mm). (Time for me to buy a digital caliper as well!)

Can the prospective new manufacturer(s) prepare realistic samples in different size options for us to compare?

[fluppeteer]

Can the prospective new manufacturer(s) prepare realistic samples in different size options for us to compare?

I suspect that'll be a big ask. One of them (who hasn't got back to me yet) indicated that they might be able to make some samples, but other may well not - the process is likely mass production or nothing. I can check, but I wouldn't hold out much hope.

Of course, arguably we already have samples of different sizes. Often within one wink.

[madsquopper]

I measured my "tournament" sets which contain more uniform winks than a random selection. Offhand, I think the ones I culled are slightly thinner than the average of all winks. Thicknesses can vary quite a lot. For my sets, the average thickness of the smalls is about 1.7mm, and for the bigs it is slightly less, at 1.65. Diameters are about what everyone else reported. So if we specify 1.75mm thickness for both then that's pretty close to what I see.

I think a tolerance of .25mm is too much. That's close to 15% and I would think decent manufactures could do a lot better. I'd aim for .1mm, or even .05. Standard tolerances for plastic manufacturing (and there are several methods) seem to be 1 or 2 percent.

[fluppeteer]

Thanks, Larry. I'll chase people and see whether there's been a reply - my entire home internet went offline a week ago (for two independent reasons), and I've been fixing it. I have a new machine up with my data on it; if I'm lucky, I'll have everything back online tonight, and be able to see who's been emailing me.

[hatj2]

I think this isn't a priority; instead, I think we should wait until we have a new source of winks that are good and work, and legislate around them.