God Bless America!

[Zermelo]

21 minutes ago, Pompey Monkey said:

Godwin's Law!

Well, I never knew that phenomenon had a name

[Marvin Jenkins]

I was having a conversation with a friend about the cost of a Stair (or is it Stare) of wood and he replied that he need to order two cord of wood! Still scratching my head.

Marv

[Macavity]

The inch - Along with some other (historical!) European measurements
was quite convenient... Simply more "people sized" than mm/cm etc. 🤔

Though, the sheer amount of TIME, I have spent on Online Websites...
checking size of BSF/BSW/Metric/Photo Threads/clearance/pitch/etc.
SWG/AWG wire... Electronics (Chips) will remain 0.1" (2.54mm) pitch? 😏

Edited November 3, 2021 by Macavity

[johninderby]

7 minutes ago, Marvin Jenkins said:

I was having a conversation with a friend about the cost of a Stair (or is it Stare) of wood and he replied that he need to order two cord of wood! Still scratching my head.

Marv

Having lived in Canafa well used to the cord as a unit used for wood.

 

From the net:

The cord is a unit of measure of dry volume used to measure firewood and pulpwood in the United States and Canada.

A cord is the amount of wood that, when "racked and well stowed" (arranged so pieces are aligned, parallel, touching and compact), occupies a volume of 128 cubic feet (3.62 m3).[1]This corresponds to a well-stacked woodpile 4 feet (122 cm) high, 8 feet (244 cm) wide, and 4 feet (122 cm) deep; or any other arrangement of linear measurements that yields the same volume.

The name cord probably comes from the use of a cord or string to measure it.[2]

The cord-foot was a US unit of volume for stacked firewood, four feet long, four feet wide and one foot high—equal to one eighth of a cord.[3] Symbol for the unit was cd-ft.[4]

Edited November 3, 2021 by johninderby

[UKDiver]

4 hours ago, Carbon Brush said:

I accept inch measurement when dealing with vehicles or other machines that are 50 years old. But for anything else. It is a joke.

Your metric/imperial issues are trivial compared to the number of large passenger and freight aircraft that have crashed or glide landed after mixing fuel units. Kilogrammes. pounds. litres, gallons......

I once had an argument with a flying examiner on a check. He asked me the fuel capacity of the aircraft.
I gave an answer in litres. He wanted an answer in US gallons - because that was the number stated in the flight manual when the aircraft was imported.
I pointed out the aircraft was fuelled from a pump delivering in litres, I know the fuel burn in litres/hour.
I know the fuel weighs 720g/litre, and the aircraft dry weight in Kg so can easily calculate take off requirements.
So for a US gallons capacity - I have no idea and I think you are daft for asking while we are flying in the UK.
I still passed the check!

The Gimli Glider is an amazing story.

3 hours ago, DaveS said:

Regarding coinage, skip to the end where he gives reasons why 240 pence to the pound isn't so crazy after all.

I've not watched the video, but 60 is dividable by enough numbers to be very flexible. Try getting 1/3 of £1...

3 hours ago, Zermelo said:

You forgot chains! Still very important to some people.

Though I never came across anyone who used rods, poles and perches. I have a suspicion that all of those "useful conversions" tables just copied from each other.

Chains are a physical thing and not just an Imperial dimension. Chains can be metric or Imperial and different lengths with different link lengths exist and can be up to 30m or 100' long. The Revenue Chain is 33feet long which is half an Imperial Chain.

[Mr Spock]

I can say without thinking how many kgs there are in, for example, 1.375 tonnes.

Without a calculator, tell me in an instant how many pounds there are in 1.375 tons 

Let's make it easier. Do the same calculation, in a split second, for grams and ounces 

[Macavity]

5 minutes ago, UKDiver said:

Chains are a physical thing and not just an Imperial dimension...

All sort of considerations might come in? The physical strength of materials? 😉

Worst case scenario is when you try to e.g. MATCH the "aesthetics" of (for me) an
Electronics (Synth) *Front Panel* and you measure across 10 knobs (9 "gaps") and
get 9.17 inches? lol. Was it made to the imperial or metric... or WHAT standard?!?

This probably has something to do with BRAND loyalty/returning customers? 🥳

P.S. Sometimes matching Tube Rings and OTA diameters can be like this too? 🤡

[Alien 13]

7 minutes ago, Macavity said:

All sort of considerations might come in? The physical strength of materials? 😉

Worst case scenario is when you try to e.g. MATCH the "aesthetics" of (for me) an
Electronics (Synth) *Front Panel* and you measure across 10 knobs (9 "gaps") and
get 9.17 inches? lol. Was it made to the imperial or metric... or WHAT standard?!?

This probably has something to do with BRAND loyalty/returning customers? 🥳

P.S. Sometimes matching Tube Rings and OTA diameters can be like this too? 🤡

I have built and still build a lot of electronic equipment and as well as having to contend with both imperial/metric I often need another measure like a bottle top/fag paper etc. Even PCB layout packages get stumped sometimes if you have the "snap to grid" option turned on.

Alan

[Xoc1]

A long time ago I asked a storeman to source some metric drills. The factory only had imperial drill sets at the time.

He took a long time about it and then complained that they were almost impossible to source. I asked what sizes he had looked at .  25.4 mm 19.05mm 12.7mm.........

[Jonk]

When I was a kid my mum used to send to the local coop....loaf of bread (19p), 2 pints of milk (can't remember the price) and a pound of Cheddar cheese from the counter.

I could never understand why the cheese didn't cost a quid, I just asked for it!

[Mognet]

10 hours ago, Carbon Brush said:

This evening I might relax with a 0.568 litre glass of beer.

I have almost the ideal glass for that. Except it only measures lager apparently 🤣

 

[Carbon Brush]

@Macavity Electronics (Chips) will remain 0.1" (2.54mm) pitch?

Almost all new chips produced now, and for the past decade, have been surface mount and often with sub-millimetre lead pitch.
About the only 'inch' devices are surface mount with 1.27 or 0.05" pitch. Even they are not generally seen in manufacturers new products.

The only 0.1" pitch , dual in line package, devices are 'mature' products.
These serve largely the repair market and as a by product, the hobby market.
Both are tiny markets compared to new build for consumer (home & automotive) use.

In fact through hole small components generally are now the preserve of hobbyists, and to some extent education.
Sadly education seems to be going the way of on screen circuit simulation and everything difficult by software. No hands on build.
But that is departing from topic. Sorry.

David.

 

[Mognet]

2 hours ago, Carbon Brush said:

Almost all new chips produced now, and for the past decade, have been surface mount and often with sub-millimetre lead pitch.
About the only 'inch' devices are surface mount with 1.27 or 0.05" pitch. Even they are not generally seen in manufacturers new products.

I used to work for a solder paste stencil manufacturer and the customer designs we received were always in imperial units. Pitches were measured in thousandths of an inch at the time, the finest pitch we'd usually see was 0.008" (I think) and occasionally an experimental 0.004" for one of the universities

That was 25 years ago and I haven't kept up with the modern practices so they may have switched to metric now. Never questioned it at the time even though the UK was already mostly metric by then. Possibly a lot of designs originated in the US?

[Carbon Brush]

@Mognet The US origin was the DIL package from the late 60s and early 70s. It has pins on 0.1" pitch.
Popularised by the '74xx' series logic family, initially produced by Texas instruments (TI).
Through hole component manufacturers used to give dimensions for fixing in inches.
Basically because a piece of 0.1" grid film made a good basis for working on a circuit board layout that often combined DIL package chips with other components.
This was  before computer based PCB layout was a practical and affordable idea. I mean before desktop or personal computer days!
In those days I designed a lot of 'eurocard' size boards, 100 x 160mm to fit into racks. No prizes for guessing the origin of this standard.
But the boards were often populated by DIL package parts so I had to convert 100 x 160mm to 3.95" x 6.3" to fit the grid!

These days virtually every electronic device data sheet (including those from TI) has metric primary units. A few have inches as a secondary unit.

In my work I encounter sensors and the like for the oil industry. This is very much USA driven.
Manufacturers for this market still work in mediaeval measurements. PSI, Farenheit, US gallons - the lot!
A real pain to translate into units the rest of world understands.

[Mognet]

That would explain the use of Imperial measurements at the time. I never saw things at the PCB design stage, it was only the solder paste stencil design stage. Lots of comparing drawings on a lightbox and staring down measuring microscopes while calculating percentages in my head

Sounds like the oil industry may be worse!

[Louis D]

Why haven't time units gone decimal?

[wulfrun]

9 minutes ago, Louis D said:

Why haven't time units gone decimal?

Don't say that too loudly 😉

Probably because 60 and 24 are more sensible in terms of how they divide.

EDIT: Compare with degrees and their decimalised version, Gradians. No-one sane uses Gradians.

Edited November 4, 2021 by wulfrun

[johninderby]

Speaking of decimal time. 😁

https://en.wikipedia.org/wiki/Decimal_time

Edited November 4, 2021 by johninderby

[Tiny Clanger]

15 minutes ago, wulfrun said:

Don't say that too loudly 😉

Probably because 60 and 24 are more sensible in terms of how they divide.

EDIT: Compare with degrees and their decimalised version, Gradians. No-one sane uses Gradians.

Aaargh, mils & radians ... I've come across particularly mind mangling geocaching puzzles using those , set by an ex forces guy who became a fire fighter and had a fondness for hiding the containers you needed to find to complete the puzzle high up trees or in small caves in a quarry wall ...

[Piero]

When I started the construction of my dobson, I largely used the book The dobsonian telescope by Kriege (= American, imperial units for everything). I thought that finding components in imperial units in the UK was easier than finding the same in metric units.

The truth: it was a serious headache. Whilst one can find some bolts, nuts, drill bits, etc in imperial units, the available choice is considerably smaller than the equivalent components in metric units. A few components are just available in metric units. During the development of my reflector I switched over to metric. For instance, my mirror cell uses 3/8-24 UNF collimation bolts, but M8 bolts for mounting the cell to the MB. The stainless steel collimation hand knob were only available with metric threads. So I had to buy them as threaded for M8, and then I had to break the thread and tap it for 3/8-24 UNF as the holes in the rungs were already tapped for this kind of bolt. Useless work.

I do prefer the inch to the centimetre because the former is larger and I find it easier to see the ticks. Said this, when / if I'm going to refactor my 12" f6 Lukehurst dobson, I will use metric units from the very beginning.

[Pompey Monkey]

35 minutes ago, Piero said:

if I'm going to refactor my 12" f6 Lukehurst dobson, I will use metric units from the very beginning.

In that case, surely it's a 304.8 mm f6? 😇

Edited November 4, 2021 by Pompey Monkey

[wimvb]

Oh, guys. Stop complaining. (I better insert one here: 😉) At least we've settled on a standard foot. When the Swedish, 18th century shipwright Fredrik af Chapman wrote (and drew) his Architectura Navalis Mercatoria, he had to deal with three measures: Swedish, English, and French feet.

The Swedish battleship Wasa (which sank on its maiden voyage less than a mile from where it was built) was found to be quite lopsided. In its wreckage, measuring sticks of at least two different units were found. Dutch and English carpenters had worked on the ship, and it is very likely that they kept to their own system of units ...

Btw, the Swedish mile is the only non-standard unit conforming to the decimal system; it's a distance of 10 kilometers.

[Guest]

Quite few years ago when there was a lot of talk about changing to metric units there was a radio phone in program where the government minister responsible was trying to answer callers questions. One angry caller ranted for a while and then asked -"For example how many kilograms in a fluid ounce?". The minister was banjaxed and couldn't answer the question. Of course it was a good example of why metric units are useful which she should have known.

I think the old units are very interesting. When I was a kid I read that a cubit length was the distance between the elbow and the tip of the middle finger. It was explained that this was good because it was a readily available measure. Of course it did mean that one persons cubit was different to another persons cubit but it did make perfect sense to me as a kid.

I find the distance units in astronomy slightly annoying. We have light years, parsecs, and astronomical units.  I know what they all are but wouldn't it make more sense from a metric point of view to settle on say parsecs and then have milliparsecs, megaparsecs, kiloparsecs  and so on for much bigger and smaller distances and then drop light years and astronomical units.

[johninderby]

More than you ever wanted to know about the foot. 🙀

https://en.wikipedia.org/wiki/Foot_(unit)

And other units of measurement.

https://en.wikipedia.org/wiki/List_of_unusual_units_of_measurement

Edited November 4, 2021 by johninderby

[Captain Scarlet]

1 hour ago, Pompey Monkey said:

In that case, surely it's a 304.8 mm f6? 😇

The Skywatcher 300p is in fact 305mm (at least, mine was). Whereas the Orion Optics VX12 and CT12 are 300mm diameter!!

Edited November 4, 2021 by Captain Magenta