3 points and 100 fine for tyre on 1.5.7

[johnfm]

Foliage said:

ging84 said:

Foliage said:

sigh, if you mean -0.05mm then firstly get it right, secondly that's not the law the only thing that matters is that its less than 1.6,

Why people are defending the op god only knows, in the original post the OP states that the tyre was also measured at one point as 1.3mm which is clearly illegal..

What I have tried multiple times to say is what simply that 1.57mm is equally to 1.6mm not less than it. No one seems to be able to get there head around the concept of taking measurements to different levels of accuracy. The law makers were more than capable of understanding that if they wanted even 0.01mm under they could have made it abundantly clear by putting 1.60mm, but they did not, we cannot assume that was an over sight so we must assume that it was deliberate and that they only wanted to class tyres as illegal when they were less than 1.6mm taken to the nearest 0.1mm, to me that is what is black and white. For all we know there could have been a debate about should it be 1.6 or 1.60 and the law makers did not want the police to be able to whip out a more acurate gague and effectively make a good half of all 1.6mm tyres illegal which was not the intention at all
I'd like to see some case law on a similar issue of measurement which has been ruled the other way.

Seriously... 1.6mm and 1.60mm are the same, 1.57mm is not 1.6mm, in your primary school maths class of rounding up and down it probably is BUT in the real world engineers and designers (of which I'm both) decide how to round the measurement and in this case as its a area of with a safety concern 1.57mm would be rounded down to 1.5mm if it was deemed that the measuring device wasn't accurate enough.

Why is this such a problem for you to understand? I fully understand what your saying BUT your wrong, putting yourself and others at risk because of semantics is simply short sighted.

Surprised that an engineer thinks that 1.6 and 1.60 represent the same thing. To me it is pretty clear that if someone provides a dimension like 12.45323344mm, I can expect whatever device they are using can measure to that accuracy and that the level of precision is required to that extent. I'm with Ging84 - had the legal draftsmen intended for the tread depth of a tyre to be measured in 1/100ths of a mm, they would have specified it.

[Cat]

There is of course the possibility that the actual measurement was 1.47mm and the officer then added 0.1mm to this to allow for the potential inaccuracy of the device.

Cat

[herewego]

johnfm said:

Foliage said:

ging84 said:

Foliage said:

sigh, if you mean -0.05mm then firstly get it right, secondly that's not the law the only thing that matters is that its less than 1.6,

Why people are defending the op god only knows, in the original post the OP states that the tyre was also measured at one point as 1.3mm which is clearly illegal..

What I have tried multiple times to say is what simply that 1.57mm is equally to 1.6mm not less than it. No one seems to be able to get there head around the concept of taking measurements to different levels of accuracy. The law makers were more than capable of understanding that if they wanted even 0.01mm under they could have made it abundantly clear by putting 1.60mm, but they did not, we cannot assume that was an over sight so we must assume that it was deliberate and that they only wanted to class tyres as illegal when they were less than 1.6mm taken to the nearest 0.1mm, to me that is what is black and white. For all we know there could have been a debate about should it be 1.6 or 1.60 and the law makers did not want the police to be able to whip out a more acurate gague and effectively make a good half of all 1.6mm tyres illegal which was not the intention at all
I'd like to see some case law on a similar issue of measurement which has been ruled the other way.

Seriously... 1.6mm and 1.60mm are the same, 1.57mm is not 1.6mm, in your primary school maths class of rounding up and down it probably is BUT in the real world engineers and designers (of which I'm both) decide how to round the measurement and in this case as its a area of with a safety concern 1.57mm would be rounded down to 1.5mm if it was deemed that the measuring device wasn't accurate enough.

Why is this such a problem for you to understand? I fully understand what your saying BUT your wrong, putting yourself and others at risk because of semantics is simply short sighted.

Surprised that an engineer thinks that 1.6 and 1.60 represent the same thing. To me it is pretty clear that if someone provides a dimension like 12.45323344mm, I can expect whatever device they are using can measure to that accuracy and that the level of precision is required to that extent. I'm with Ging84 - had the legal draftsmen intended for the tread depth of a tyre to be measured in 1/100ths of a mm, they would have specified it.

It's ridiculous expecting to read 0.01mm in rubber anyway. The device shouldn't display the second place.

[WinstonWolf]

BertBert said:

So further, this...
http://www.ebay.co.uk/itm/39590-Brand-New-Draper-D...

Displays to 2DP (for mm) and is accurate +-.01mm, so not accurate to 2DP

BertBert said:

WinstonWolf said:

If it reads to 2DP it's accurate to 2DP.

Do you *know* that? I'm not saying it's not, just wondering how you know.
Bert

So the MAXIMUM error could be 1.58 or 1.56 for a recording of 1.57. That's still illegal.

[BertBert]

herewego said:

It's ridiculous expecting to read 0.01mm in rubber anyway. The device shouldn't display the second place.

Unless it's there to allow an accurate 1 DP measurement!

[WinstonWolf]

johnfm said:

Foliage said:

ging84 said:

Foliage said:

sigh, if you mean -0.05mm then firstly get it right, secondly that's not the law the only thing that matters is that its less than 1.6,

Why people are defending the op god only knows, in the original post the OP states that the tyre was also measured at one point as 1.3mm which is clearly illegal..

What I have tried multiple times to say is what simply that 1.57mm is equally to 1.6mm not less than it. No one seems to be able to get there head around the concept of taking measurements to different levels of accuracy. The law makers were more than capable of understanding that if they wanted even 0.01mm under they could have made it abundantly clear by putting 1.60mm, but they did not, we cannot assume that was an over sight so we must assume that it was deliberate and that they only wanted to class tyres as illegal when they were less than 1.6mm taken to the nearest 0.1mm, to me that is what is black and white. For all we know there could have been a debate about should it be 1.6 or 1.60 and the law makers did not want the police to be able to whip out a more acurate gague and effectively make a good half of all 1.6mm tyres illegal which was not the intention at all
I'd like to see some case law on a similar issue of measurement which has been ruled the other way.

Seriously... 1.6mm and 1.60mm are the same, 1.57mm is not 1.6mm, in your primary school maths class of rounding up and down it probably is BUT in the real world engineers and designers (of which I'm both) decide how to round the measurement and in this case as its a area of with a safety concern 1.57mm would be rounded down to 1.5mm if it was deemed that the measuring device wasn't accurate enough.

Why is this such a problem for you to understand? I fully understand what your saying BUT your wrong, putting yourself and others at risk because of semantics is simply short sighted.

Surprised that an engineer thinks that 1.6 and 1.60 represent the same thing. To me it is pretty clear that if someone provides a dimension like 12.45323344mm, I can expect whatever device they are using can measure to that accuracy and that the level of precision is required to that extent. I'm with Ging84 - had the legal draftsmen intended for the tread depth of a tyre to be measured in 1/100ths of a mm, they would have specified it.

Can you fit a 1.6mm shaft in a 1.57mm hole?

[silentbrown]

johnfm said:

Surprised that an engineer thinks that 1.6 and 1.60 represent the same thing.

You shouldn't be, because they do: Numbers represent 'point values', not ranges. If an engineer needs to add some 'inexactitude' to a number (e.g. a measurement), it's expressed with a tolerance : 10mm +/-0.1mm, means the range from 9.9mm to 10.1mm.

[ging84]

WinstonWolf said:

Can you fit a 1.6mm shaft in a 1.57mm hole?

Fit my tiny shaft into an even smaller hole?
owww yeaaah

No seriously this thread has got out of hand, it comes down to 2 issues

1. are statutory values absolute or not, ORD is convinced they are, I'm yet to be convinced on this

2. Is the measurement correct and accurate at that level, i don't believe that is possible, as you might be able to send coppers out with a calibrated depth guage accurate to 0.01mm or better, but can you expect their method of measuring the depth out in the field to maintain that level of precision? I don't believe you can

[Corpulent Tosser]

The law states a minimum tread of 1.6mm, it doesn't give a tolerance because no tolerance is required.

Engineering terms have been discussed, and sometimes on an engineering drawing there will be a a table stating something along the lines of
1 decimal point plus or minus 0.1, 2 decimal points plus or minus 0.05, etc

This only applies if a tolerance is not otherwise stated on the drawing, the stated tolerance might be +0.01 -0.00, so the dimension given wouldn't be a mean, it would be a minimum. That is what the tyre tread depth is, a minimum.

[MrPicky]

WinstonWolf said:

If it reads to 2DP it's accurate to 2DP.

You are confusing accuracy with precision there WW, if you wanted to say that in a properly engineered and calibrated system then I would agree with you.

Manufacturers of far eastern equipment have always been fond of adding extra precision to engineering tools - playing the numbers game when that precision is never possible.

I have a clock that reads hours, minutes and seconds, do you think that it is always accurate to the second?

[Devil2575]

WinstonWolf said:

Can you fit a 1.6mm shaft in a 1.57mm hole?

You might be able to because 1.6 mm could actually be 1.56mm

I suspect what you actually mean is 1.60, not 1.6

The number of decimal places indicates the accuracy of the measurement.

[Pothole]

MrPicky said:

WinstonWolf said:

If it reads to 2DP it's accurate to 2DP.

You are confusing accuracy with precision there WW, if you wanted to say that in a properly engineered and calibrated system then I would agree with you.

Manufacturers of far eastern equipment have always been fond of adding extra precision to engineering tools - playing the numbers game when that precision is never possible.

I have a clock that reads hours, minutes and seconds, do you think that it is always accurate to the second?

Accurate to what? Time is a nebulous concept.

[herewego]

BertBert said:

herewego said:

It's ridiculous expecting to read 0.01mm in rubber anyway. The device shouldn't display the second place.

Unless it's there to allow an accurate 1 DP measurement!

It should round it's reading to 1 DP.

[MrPicky]

Pothole said:

Accurate to what? Time is a nebulous concept.

Lunchtime doubly so! (HHGG).

So is linear measurement, both used for relative measurement that can ultimately be referenced to a global standard based upon the transitions of electrons in Caesium atoms (which as humans we can't experience directly).

The concept of a metre bar went out of the window a few years ago, even the kilogram is losing mass gradually.

[MrPicky]

Devil2575 said:

WinstonWolf said:

Can you fit a 1.6mm shaft in a 1.57mm hole?

You might be able to because 1.6 mm could actually be 1.56mm

I suspect what you actually mean is 1.60, not 1.6

The number of decimal places indicates the accuracy of the measurement.

According to Wikipedia <http://en.wikipedia.org/wiki/Engineering_tolerance> the standard tolerance for 1 DP is plus or minus 0.1 and for 2DP is plus or minus 0.01.

so "Can you fit a 1.6mm shaft in a 1.57mm hole?" 1.6 could be as small as 1.5 and 1.57 could be as large as 1.58 - so no problem.

If WW meant 1.60mm then this could be as small as 1.59.

Can you fit a 1.59mm shaft in a 1.58mm hole? - no problem with a big enough hammer.

"

[BertBert]

Corpulent Tosser said:

The law states a minimum tread of 1.6mm, it doesn't give a tolerance because no tolerance is required.

There is no tolerance in the limit, but as it is impossible to measure a thing in the real world to infinite accuracy, tolerance in the measuring system has to be there. I can measure much more accurately with my dial gauge than with a ruler marked in whole cm.
Bert

[blueg33]

BertBert said:

Corpulent Tosser said:

The law states a minimum tread of 1.6mm, it doesn't give a tolerance because no tolerance is required.

There is no tolerance in the limit, but as it is impossible to measure a thing in the real world to infinite accuracy, tolerance in the measuring system has to be there. I can measure much more accurately with my dial gauge than with a ruler marked in whole cm.
Bert

Which of course is why the police use an approved measuring device. One would expect the level of tolerance to be built into the device

[Jimmyarm]

blueg33 said:

Which of course is why the police use an approved measuring device. One would expect the level of tolerance to be built into the device

This, they presumably use gauges approved for MOT use. I have a digital one that can be calibrated and is accurate to +/- 0.01 mm out of the box apparently