Metric meets imperial

[Ken82]

Thanks to StubMandrel  I now have a converted ADM losmandy plate that fits my primalucelab scope rings. Isn’t it a pain the US work in imperial and Europe work in metric ! 
 

I actually had to visit my local fasteners for some bolts and the shop owner asked me what they were for. When I told him a telescope he told me all about his Sky-Watcher and HEQ5. Just think it’s great to find other like minded astronomers 😀 so got his number ! 
 

ken 
 

 

[Gina]

FLO sell both metric and imperial versions.

[Captain Scarlet]

One of my first used and upgrade purchases getting into this pastime (don't like the word hobby) was an ADM saddle for my AZ EQ6. When it arrived I couldn't understand why my hex keys wouldn't properly fit. Then I thought "surely not Imperial in this day and age..." and of course so it was.

[andrew s]

It always amuses me that the land of the free use Imperial units.

Free choice? 

Regards Andrew 

[wimvb]

8 minutes ago, Captain Magenta said:

surely not Imperial in this day and age...

Of course the Empire strikes back. 😉

[Mr Spock]

Technically, the US uses English measurements and not Imperial. The two standards diverged many years ago with the US choosing not to adopt Imperial. 

So, they are two steps behind not one 😜 Very frustrating when you are trying to juggle both English and Metric.

[Astro-Geek]

What amazes me the most is that even the most modern and expensive digital cameras in the world still invariably have a 20 x 1/4 UNF tripod bush, as does almost every camera tripod ! 🤓

We Astronomers then suffer with the hotch potch of tapped threads found on dovetail bars and scope rings.......

Edited June 11, 2020 by Astro-Geek

[vlaiv]

6 minutes ago, Mr Spock said:

Technically, the US uses English measurements and not Imperial. The two standards diverged many years ago with the US choosing not to adopt Imperial. 

So, they are two steps behind not one 😜 Very frustrating when you are trying to juggle both English and Metric.

According to wiki (I had to look it up since this is the first time I saw that English and Imperial units are different thing), American units are further evolution of English units.

Therefore - not two steps behind, but two steps behind and one to the side

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

[Gina]

Cameras originally had 1/4" Whitworth - 20 x 1/4" UNC is a close approximation.

[vlaiv]

While we are on the subject, can anyone explain this graph:

[sloz1664]

6 minutes ago, Gina said:

Cameras originally had 1/4" Whitworth - 20 x 1/4" UNC is a close approximation.

UK meets USA

Steve

[Filroden]

19 minutes ago, vlaiv said:

While we are on the subject, can anyone explain this graph:

Can't say I understand it all, but the boxes with italics are qualifiers to the metric in upright text, so a troy ounce or troy pound. If I read it correctly, there are 12 troy ounces in a troy pound and 15 troy ounces in a london pound. The different qualifiers come from the different types of things they are measuring. Troy is usually a measure of weight for precious metals. So this is a relationship diagram for all English weights (some of which are no longer used).

 

Wiki show a nice timeline for how weights and measures changed over the last 800 years:

Quote

 

Timeline

Selected excerpts from the bibliography of Marks and Marking of Weights and Measures of the British Isles

1215 Magna Carta — the earliest statutory declaration for uniformity of weights and measures

1335: 8 & 9 Edw III c1 — First statutory reference describing goods as avoirdupois

1414 2 Hen V c4 — First statutory mention of the Troy pound

1495 12 Hen VII c5 — New Exchequer standards were constructed including Winchester capacity measures defined by Troy weight of their content of threshed wheat by stricken measure (first statutory mention of Troy weight as standard weight for bullion, bread, spices etc.).

1527 Hen VIII — Abolished the Tower pound

1531 23 Hen VIII c4 — Barrel to contain 36 gallons of beer or 32 of ale; kilderkin is half of this; firkin is half again

1532 24 Hen VIII c3 — First statutory references to use of avoirdupois weight

1536 28 Hen VIII c4 — Added the tierce (41 gallons)

1588 (Elizabeth I) — A new series of Avoirdupois standard bronze weights (bell-shaped from 56 lb to 2 lb and flat-pile from 8 lb to a dram), with new Troy standard weights in nested cups, from 256 oz to 1/8 oz in a binary progression.

1601–1602 — Standard bushels and gallons were constructed based on the standards of Henry VII and a new series of capacity measures were issued.

1660 12 Chas II c24 — Barrel of beer to be 36 gallons, taken by the gauge of the Exchequer standard of the ale quart; barrel of ale to be 32 gallons; all other liquors retailed to be sold by the wine gallon;

1689 1 Wm & Mary c24 — Barrels of beer and ale outside London to contain 34 gallons

1695 7 Will III c24 — Irish Act about grain measures decreed: unit of measure to be Henry VIII's gallon as confirmed by Elizabeth I; i.e. 272 1/4 cubic inches; standard measures of the barrel (32 gallons), half-barrel (16 gallons), bushel (8), peck (2), and gallon lodged in the Irish Exchequer; and copies were provided in every county, city, town, etc.

1696 8 & 9 Will III c22 — Size of Winchester bushel "every round bushel with a plain and even bottom being 18 1/2" wide throughout and 8" deep" (i.e. a dry measure of 268.8 in³ per gallon).

1706 5 & 6 Anne c27 — Wine gallon to be a cylindrical vessel with an even bottom 7" diameter throughout and 6" deep from top to bottom of the inside, or holding 231 in³ and no more.

1706 6 Anne c11 — Act of Union decreed the weights and measures of England to be applied in Scotland, whose burgs (towns) were to take charge of the duplicates of the English Standards sent to them.

1713 12 Anne c17 — The legal coal bushel to be round with a plain and even bottom, 19 1/2 inch from outside to outside and to hold 1 Winchester bushel and 1 quart of water.

1718 5 Geo I c18 — Decreed Scots Pint to be exactly 103 in3.

1803 43 Geo III c151 — Referred to wine bottles making about 5 to the wine gallon (i.e. Reputed Quarts)

1824 5 Geo IV c74 — Weights and Measures Act completely reorganized British metrology and established Imperial weights and measures; defined the yard, troy and avoirdupois pounds and the gallon (as the standard measure for liquids and dry goods not measured by heaped measure), and provided for a 'brass' standard gallon to be constructed.

1825 6 Geo IV c12 — Delayed introduction of Imperial weights and measures from 1 May 1825 to 1 January 1826.

1835 Will IV c63 — Weights and Measures Act abolished local and customary measures, including the Winchester bushel; made heaped measure illegal; required trade to be carried out by avoirdupois weight only, except for bullion, gems and drugs (which were to be sold by troy weight instead); decreed that all forms of coal were to be sold by weight and not measure; legalised the 14 lb stone, the 112 lb hundredweight, and the 20 hundredweight ton.

1853 16 & 17 Vict c29 — Permitted the use of decimal Bullion weights.

1866 29 & 30 Vict c82 — Standards of Weights, Measures and Coinage Act transferred all duties and standards from the Exchequer to the newly created Standards Department of the Board of Trade.

1878 41 & 42 Vict c49 — Weights and Measures Act defined the Imperial standard yard and pound; enumerataed the secondary standards of measure and weight derived from the Imperial standards; required all trade by weight or measure to be in terms of one of the Imperial weights or measures or some multiple part thereof; abolished the Troy pound.

1963 11 & 12 Eliz II c31 — Weights and Measures Act abolished the chaldron of coal, the fluid drachm and minim (effective 1 February 1971), discontinued the use of the quarter, abolished the use of the bushel and peck, and abolished the pennyweight (from 31 January 1969).

 

Glad I was brought up with metric measures!!

[skybadger]

I suspect cameras still have 1/4 whitworth for the threads, unc just happens to fit  in spite of the different apex angle. 

[MarkAR]

38 minutes ago, vlaiv said:

While we are on the subject, can anyone explain this graph:

Oh that's soooooo easy.

Very light, light, fairly light, medium light, medium, bit heavier, that makes my arms ache, my backs going, Dave get the forklift.

On a more serious note, I think grain was one grain of wheat, 24 weight the same as an old penny. Then it starts matching equivalent coinage to weights and volumes. 

Avoirdupois ounces annoyed me as being a goldsmith everything used to be measured in Troy ounces. Now it's grams I used to have to run through all sorts of conversions until some handy apps appeared for my iPhone.

Edited June 11, 2020 by MarkAR

[wimvb]

59 minutes ago, Filroden said:

 

Glad I was brought up with metric measures!!

Me 24/12 😉

[wimvb]

1 hour ago, Astro-Geek said:

We Astronomers then suffer with the hotch potch of tapped threads found on dovetail bars and scope rings.......

So do plumbers

[saac]

1 hour ago, vlaiv said:

While we are on the subject, can anyone explain this graph:

Yes I can explain it - it's the reason we adopted the SI system

[andrew s]

I prefer natural units c = h bar = 1 etc. Not much good for cooking though.

Regards Andrew 

[vlaiv]

This one is easy

Although not quite coherent. If you follow the graph from foot to nautical mile, you will conclude that:

nautical mile = 10 cable = 10 x (100 fathom) = 10 x 100 x (2 x yard) = 10 x 100 x 2 x (3 foot) = 10 x 100 x 2 x 3 x foot = 6000 x foot = 6080 x foot (if you go directly)

We have 80 feet (11520 poppy seeds) missing in our calculation - or about one shackle

 

[DaveS]

2 hours ago, vlaiv said:

While we are on the subject, can anyone explain this graph:

Had to learn all that gobbledygook at primary school. So damn glad we went metric.

Yes, the camera tripod screw is 1/4" Whitworth, and just to compound the felony, the tripod screw itself to connect the head is 3/8" whitworth, Argh! I still have dad's collection of imperial taps and dies.

Edited June 11, 2020 by DaveS

[DaveS]

Yep, got dad's set of BA taps all the way from 0BA down to some ridiculous number, including the odd numbers that you don't see very often. Also have some of his BSP taper taps. Not surprising that he had all that stuff as he was a toolmaker.

[tomato]

I spent my entire working life in contract chemical manufacture and used to take a deep breath when we received a tech package from our American customers full of lbs, US gallons and degrees F. So much scope for error with expensive (or worse) consequences.

A number of them did go metric over the years but not all. 

[Gina]

My dad was a toolmaker too (amongst other things).

[Ibbo!]

When i was lad in my first job out of school, woking in the lab at a coke oven plant some of you might of heard of -Orgreave (Choke and Chemicals as it was commonly known) we had to measure something in grains /hundred cubic feet as that was what the old tables listed.

Thing is we could not get gas meters that measured in cubic feet and the tests were done in SI units and instead of converting the tables we had to convert the result.

 

[johnturley]

14 minutes ago, Ibbo! said:

When i was lad in my first job out of school, woking in the lab at a coke oven plant some of you might of heard of -Orgreave (Choke and Chemicals as it was commonly known) we had to measure something in grains /hundred cubic feet as that was what the old tables listed.

Thing is we could not get gas meters that measured in cubic feet and the tests were done in SI units and instead of converting the tables we had to convert the result.

 

I remember the old Orgreave Coking Plant well, used to sample the effluent there initially on behalf of Yorkshire Water Authority, and then later the National Rivers Authority.

I expect that you also used to measure the strength of the caustic soda in degrees twaddle.

John