When gauge sizes differ

[quietly]

Hi
I get fed up with only using wires so I thought I'd make up a couple of 2 in 1 picks.
So, I made 2 sizes in what I thought was 5 gauge (5.4mm) and 6 gauge (4.75mm).
Only to discover that the 5 gauge was way too small (loads of wobble space) in a Chubb 5 gauge 3 lever lock I was messing round with.
Going to the mutipick website and a couple of other reference sites, I now see a number of sizes quoted for the 5 gauge ranging from 5.3 to 6.2mm.
Luckily the two picks fit everything I've played with but it could have gone the other way i.e. nice picks, shame they don't fit!!!

What's going on ?
Is the term "gauge" NOT standard throughout the UK lock industry ?
Is "gauge" a measure of the key size or the keyway size ?

[gloves]

In measurement, gauge means a lot of things like: diameter of a shotgun barrel, cross-sectional area of a wire, thickness of thin plastics, thickness of metal in sheet form, outer diameter of medical needles etc. just to name a few.

The most common one I came across is wire gauge. It determines how much current a wire can safely carry. There is more than one standard, check British Standard Wire Gauge, AWG and wire gauge on wikipedia.
I am not aware of any lock manufacturer using "gauge" as keyway measurement though.

You may also find this comparison chart useful.

Also about making picks, there's this thread discussing which material is best to use www.lockpicking101.com/viewtopic.php?f=4&t=54290

Cheers

[MacGyver101]

quietly is asking about "gauge" in the sense of lever locks... and I'm afraid that I don't have a good reference handy, but I'm sure some of our UK locksmiths will chime in shortly (and with far better advice than I'd be able to provide).

[quietly]

Thank you both for replying.
I've got the chart downloaded thanks gloves and with a bit of playing round made a nice little handy laminated sheet. No more guessing!
I sat with my coffee tin full of old keys and micrometered the lot.
The difference was tiny in older keys (pre 1980's) but modern stuff seems all over the shop.
I'm beginning to cotton on that 'gauge' ain't an absolute more a "near is close enough" sort of measurement. I'm just wondering why it took me so long to see it.
Should have stuck with wire picks and not gone "high tech" I suppose.
MacGyver101, are canadian locks (in terms of gauge) different then?

[dls]

there are also half guages dont forget that, and cheap locks like basta and legge 2 levers etc will have a wide tolerance so i wouldnt base any studies on their actual size.
An old pin key will rarely ever grow in diameter with age it will wear and become thinner never mind the fact that cheap blanks like rst pin and pipe blanks are shit quality and the chrome flakes off when cut or used which can throw off the measurement.