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Old 18-09-2018, 06:43 PM
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Lognic04 (Logan)
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Small request

Hi all,
I'm making a mirror, which needs precise saggita measurements. I use coins under a steel ruler to gauge the depth, as i have no feeler gauges or a spherometer.
I'm wondering if someone would be kind enough to measure the precise thickness of a one and two dollar coin with calipers for taking measurements? (or more coins!)
I can then precisely check my saggita and also update the clearly wrong wikipedia article
Thanks!!! Hope someone can help!

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  #2  
Old 18-09-2018, 07:14 PM
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billdan (Bill)
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Here you go Logan this has all the details for you.

https://en.wikipedia.org/wiki/Coins_...tralian_dollar


EDIT: Whoops your suggesting that wikipedia is wrong, sorry about that.
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Old 18-09-2018, 07:24 PM
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eddiedunlop (Martin)
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As requested, I obtained the following measurements (in mm):

$1: 2.6, 2.5, 2.55 mean 2.55

$2: 2.7, 2.75.2.65 mean 2.7

Measurements were taken from randomly selected positions on the coin rim. I did notice a bit of variation on individual coins.
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Old 18-09-2018, 07:38 PM
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Lognic04 (Logan)
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Thanks Martin!
Seems like i have been overestimating the saggita a LOT!
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Old 18-09-2018, 11:57 PM
Saturnine (Jeff)
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Logan

If you have access to a set of metric drill bits in 0.5mm increments you can use them to slip under the steel rule edge to measure the sagita.
For arguments sake, if a 2.5mm has some play and a 3.00mm wont fit , then your sag. is somewhere in between, say 2.75mm. Theoretically you should then be able to measure to an 0.25mm accuracy, give or take a bit.
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Old 19-09-2018, 06:25 AM
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bojan
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This is the tool for you.
Or this one..

Or, if you prefer analogue.. this.
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