# Fraction calculator



## Dalboy (5 Aug 2015)

Do you still use imperial fractions when woodworking. I have found a free app for your phone take a look HERE


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## RogerP (5 Aug 2015)

I don't have a mobile but I do have a Casio fx82 Fraction calculator.

Fantastic bit of kit, works to 8 decimal places,
plus just about every mathematical function, 
plus any fractional task you care to set it. 

You can even get daft (but correct) fractional answers like 3791/4239

No user replaceable battery as the in-built one will last indefinitely the say 
(it's already 20 years old and no sign of fading).

All for a quid from a car-boot!


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## Dalboy (5 Aug 2015)

RogerP":pgzeyj72 said:


> I don't have a mobile but I do have a Casio fx82 Fraction calculator.
> 
> Fantastic bit of kit, works to 8 decimal places,
> plus just about every mathematical function,
> ...



The app I showed does it in 32nd 64th and the like no decimal points


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## RogerP (5 Aug 2015)

It looks a very handy app for those with a smart phone.


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## bugbear (5 Aug 2015)

The answer to the difficulty of fractions is (of course) to go metric.  

BugBear


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## Mark A (5 Aug 2015)

bugbear":3jpcgyfd said:


> The answer to the difficulty of fractions is (of course) to go metric.
> 
> BugBear



Where's the fun in that?


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## RogerP (5 Aug 2015)

I have a nice vernier which shows the measurement in decimal mm, decimal inches or inches expressed in a fraction.

Very useful for translating American plans.


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## mseries (5 Aug 2015)

I just do it all in my head or on paper or using millimetres


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## gregmcateer (6 Aug 2015)

I just cut the first one again to match the incorrectly cut second one, then the third one.... :lol:


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## sammy.se (7 Aug 2015)

Erm, what's a fraction?

Is that like a meter ruler, with a crack in it?


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## Monkey Mark (7 Aug 2015)




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## memzey (21 Aug 2015)

I'm 40 years old and went to school during the period where both metric and imperial standards were being taught. I've never been able to get on with metric myself. It just doesn't mean anything to me. For example if someone were to describe themselves as 186cm tall I'd have no idea what that means. If they said they were 6'3" on the other hand I'd know exactly what to expect. Same with kilos vs stones. I'd love to make my workshop metric free but unfortunately living in the UK today that is highly unlikely to happen and mores the shame for that IMHO. Brits invented a perfectly good set of standards and sacrificed them for who knows what reason. Probably something to do with the common market back in the 70's I suppose. 

Ok sorry - rant over now!


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## beech1948 (21 Aug 2015)

Fractions are easy....measure in imperial and just calculate in your head.

What on earth requires an app for this is mind boggling. A more useless app I hardly conceive of. Is this like a hammer with an electric cord.


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## Phil Pascoe (21 Aug 2015)

Metrication was undertaken partly to suit Europe (or at least the EEC) but also because (as I understand) it was understood by the powers that be that the USA would also abandon Imperial measurements - which of course it had no intention of doing.


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## Droogs (21 Aug 2015)

There are now only 3 countries in the world that do not use the metric systems units as their official units of measurement. it is far easier to use for the average person as its base 10. and to say that imperial was perfectly good, is by the by. it's no use having a system that no-one else wants to use. we changed or units in order to be able to compete on an economic basis. Even the USA is now using the metric system more and more. i also know of a very recent NASA project that just wasted a lot of money due to the fact that half of it was measured in inches and the other mm and now the bolts are too small. also please remember that the true units of measurement used globaly for accurate measurement do not use either system any more but are now in the realms of startrek. see the thread on precision.
but then for me if its under a metre for me it's mm and if over, feet :roll:


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## Angusdog (22 Aug 2015)

Droogs":1p68i7vu said:


> There are now only 3 countries in the world that do not use the metric systems units as their official units of measurement. <snip>



The US of A, Liberia and Myanmar. A fact I trot out when people wax lyrical about the imperial measurement. Having said that, I am appalled our Subaru gets 15mpg and disappointed I'm 5'11" and not 6". Hearing of people measured in stones (on UK tv), takes me back to NZ in the seventies.

Although it annoys me when I read plans in inches (mainly the 3/8" stock for example), I must admit, working out 1/2 of 7/8 is pretty easy, so long as I don't need to convert it to metric.


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## Droogs (22 Aug 2015)

Angusdog":2pjq18tj said:


> Droogs":2pjq18tj said:
> 
> 
> > There are now only 3 countries in the world that do not use the metric systems units as their official units of measurement. <snip>
> ...


*
*

Ii agree there [bold], however I think that the major problems for those that have been taught in a metric system when forced to use imperial units is that:
a) They are unable to form the fraction visually in their minds eye due to being taught to visualise fractions as a decimal figure or percentage of the whole
b) having that teaching constantly reinforced by the fact that they are generaly of the post pocket calculator generation (I damn you Sir Clive, to eternity on the M25 in a C5) and therefore don't (can't?) do mental arithmetic


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## Mark A (22 Aug 2015)

I'm the other way round: born in the metric generation, taught metric in school...but I think in imperial, and use a combination of both for measurements!

The fractions I find easy; decimals are more problematic (0.125", 0.250" and 0.50" are no problem but what the hell's 0.71875"?)


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## beech1948 (23 Aug 2015)

Despite my earlier sarcastic comment I work entirely in metric. Rather in mm and meters. Those damned centimeters make no sense. Every time I am given a measurement in cm I have to convert to mm or I have no sense of what size the item is. 

I am 67 so brought up in an imperial world and find the mental agility needed to measure in fractions, calculate fractions add or subtract fractions very easy. For things of some importance I always convert back to imperial as a sort of check. Its just comfortable since my sense of sizes originated there.

In 25 years the US will be completely metric as its only the old codgers who keep it alive.


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## Rich.ca (24 Aug 2015)

I had an app like this when I was living in Canada as frations made no sense to me, but after a while I found using imperial easier than metric. Now I'm back in the UK I feel like I'm having to re learn metric. Millimetres are too long winded and I find myself having to take a moment to actually work out what the measurement is just to comprehend it, why don't we just use centemetres and metres like we were taught in school?


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## RogerP (24 Aug 2015)

Rich.ca":25em8smk said:


> .....why don't we just use centemetres and metres like we were taught in school?


 ... I and many others of a similar advanced years weren't taught metric at school.


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## Phil Pascoe (24 Aug 2015)

Anyone using centimetres should be hung, drawn and quartered.


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## Rich.ca (24 Aug 2015)

I dont understand why we have to use mm when cm and a decimal point is far easier to read/take in. You don't say I drive 5000 metres to work each day, you'd say its 5km because its easier to understand


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## beech1948 (24 Aug 2015)

Rich,

Its like this. NASA recently blew millions of dollars and 4 yrs of effort when the measurements on thier drawings did not agree...part were imperial and part were metric.......whoops. Nothing would fit together.

millimeters and meters work very well. Its either 347mm if short of a meter or say 1.347m if longer than a meter. Same applies to meter to kilometer. Upto 999 m its meters and over 1000m its kilometers.

The centimeter has no place in this at all. Frequently people write down a cm measurement and others come look at it and assume its mm....nothing fits. Centimeters are a waste of time and space. After all up to a meter its easy to just say 522mm. Its actually mentally more difficult to say 52.2cm and have to convert that back to use a ruler.

Say no to centimeters


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## Droogs (25 Aug 2015)

beech1948,
that was my missus' cousin, she was telling me about it last week. She was pretty miffed at wasting all that time on a bolt, wasn't impressed when I suggested checking out Screwfixes latest offers. :roll:


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## woodenstx (27 Aug 2015)

I'm 34, so was dragged up on Metric but Imperial was still a large fact of life, especially with my mother doing her sewing stuff. this means I can happily cope with both types. when working on stuff that needs measuring (unless pre designed) I will use the number that is the easiest to remember or perform the maths on :lol:

I agree that CM is a completely wrong unit of measurement. If you are under 18 then sure its ok.
A friend of mine showed me a design he did for some shelves etc... 240CM long.... His design went back in m/mm :lol: he does live in Wales though so you could almost let him off.


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## lurker (28 Aug 2015)

beech1948":urj83dm2 said:


> Rich,
> 
> Its like this. NASA recently blew millions of dollars and 4 yrs of effort when the measurements on thier drawings did not agree...part were imperial and part were metric.......whoops. Nothing would fit together.
> 
> ...



I was going to mention NASA. When you mix systems you get space shuttles blowing up.


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## DiscoStu (29 Aug 2015)

In a previous company our marketing girl ordered some big brushed aluminium sheets for a stand at a show. We hired a man with a van to go and collect them and he phoned to check what he had was correct. "10 sheets of brushed aluminium is what you should have", said our boss. "That's what I've got" said the driver. "All good then" said our boss. The driver then questioned why he'd been sent to collect them. "What do you mean?" said our boss. "Well I've got the sheets but I'm holding them in the palm of my hand?"

Our marketing girl had confessed with CM and MM. 

She didn't last long.


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## MCB (13 Sep 2015)

Can anybody explain why wood is sold by 30cm lengths rather than by the metre, please?

I needed some 2m lengths during the summer but had to buy 2.1m lengths

I could only just fit it in my car!

MC


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## Phil Pascoe (14 Sep 2015)

IT's not. Try buying 2.2 metres or 3.7 metres.


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## Jacob (14 Sep 2015)

MCB":36t8u75l said:


> Can anybody explain why wood is sold by 30cm lengths rather than by the metre, please?
> 
> I needed some 2m lengths during the summer but had to buy 2.1m lengths
> 
> ...


30cm is a metric nearly one imperial foot. Timber is sold in feet.

The thing about imperial is that it's the geometers and makers system whereas metric is for counters. 
Makers often want to divide things by 2, 3, 4.., so base 12 works best and leads up to 360º or down to 1/64" (beyond which 1/1000"s become more useful)
Dividers (the instrument) would have been well used well before any standard measurements were set up. Simplest useful divider is a length of string - easily folded into 2, 3, etc and if it's long enough can even divide large areas of ground - geometry being the first maths.
Counters use their fingers - giving base 5 or 10, and also use there toes so base twenty is common all over the place - we still have it as the "score".
So it's between makers and counters.


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## DennisCA (14 Sep 2015)

Centimeters are just fine and the preferred unit of use in the nordic countries, and since switching either to m or mm takes no mental effort whatsoever, there's nothing to complain about. So all three are used here and it's no problem going back and forth.


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## MCB (14 Sep 2015)

phil.p":255td7ge said:


> IT's not. Try buying 2.2 metres or 3.7 metres.



That would NOT have been possible, unfortunately, at the builders merchant where I bought it.

And it's rather too far to drive to Cornwall to buy from yours.

MC


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## woodenstx (14 Sep 2015)

MCB":1zl59nwz said:


> phil.p":1zl59nwz said:
> 
> 
> > IT's not. Try buying 2.2 metres or 3.7 metres.
> ...



A10 timber will sell you what you want, as in they will cut it down from the 4.8M lengths they usually have, to your requirements.


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## MCB (14 Sep 2015)

woodenstuart":gl6ii8rp said:


> MCB":gl6ii8rp said:
> 
> 
> > phil.p":gl6ii8rp said:
> ...



Thank you 

I'll try and remember that next time I need timber - but it may be that the extra journey would cost more than I'd save on buying the right length.

With best wishes and thanks again. 

MC


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## Sporky McGuffin (22 Sep 2015)

The Imperial system was designed to be as complex as possible, with differing multiples of inches in feet, feet in yards, yards in rods, chains, furlongs and miles, ounces in pounds, pounds in stone, stone in hundredweight, gross, tons, blah blah blah. It gets even worse when the Americans use the same words as us but for different quantities...

One might suspect that, like formal grammar, the primary intention of the Imperial system was to create a barrier to entry, in this case to the professions and trades.

Metric is simple and consistent and the units interrelate neatly.


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## Jacob (22 Sep 2015)

Sporky McGuffin":2uwx8kja said:


> The Imperial system was designed to be as complex as possible, with differing multiples of inches in feet, feet in yards, yards in rods, chains, furlongs and miles, ounces in pounds, pounds in stone, stone in hundredweight, gross, tons, blah blah blah. It gets even worse when the Americans use the same words as us but for different quantities...
> 
> One might suspect that, like formal grammar, the primary intention of the Imperial system was to create a barrier to entry, in this case to the professions and trades.
> 
> Metric is simple and consistent and the units interrelate neatly.


It wasn't "designed" it evolved out of the needs of people working away at real things. Rods/poles/perches etc for ploughman farmers, miles/furlongs for travellers, acres for land surveyors, feet/inches/yards for builders and makers, pounds/ounces for grocers, 360º for navigators or astronomers, and so on and on.....
So if you have the right units for the job in hand they may be really handy, whereas metric is one size fits all but sometimes not conveniently


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## MCB (22 Sep 2015)

Sporky McGuffin":2gdb0xxc said:


> The Imperial system was designed to be as complex as possible, with differing multiples of inches in feet, feet in yards, yards in rods, chains, furlongs and miles, ounces in pounds, pounds in stone, stone in hundredweight, gross, tons, blah blah blah. It gets even worse when the Americans use the same words as us but for different quantities...
> 
> One might suspect that, like formal grammar, the primary intention of the Imperial system was to create a barrier to entry, in this case to the professions and trades.
> 
> Metric is simple and consistent and the units interrelate neatly.



The units in the Imperial system interrelate too

For example one gallon of pure water at 4 degrees centigrade has a mass of ten pounds

What could be simpler than that?

The Metric system was based on the idea that the metre was one ten millionth of the distance from the north pole to the equator on a meridian through Paris.

Unfortunately, the Frenchman who did the calculation got his sums wrong!

MC


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## bugbear (22 Sep 2015)

MCB":19b4rqf7 said:


> Sporky McGuffin":19b4rqf7 said:
> 
> 
> > The Imperial system was designed to be as complex as possible, with differing multiples of inches in feet, feet in yards, yards in rods, chains, furlongs and miles, ounces in pounds, pounds in stone, stone in hundredweight, gross, tons, blah blah blah. It gets even worse when the Americans use the same words as us but for different quantities...
> ...



1000 ml of water having a mass of 1 Kg, perhaps?


Anybody trying to convince themselves of the simplicity of the imperial system might want to look up how to interconvert mass between troy, avoirdupois, and apothecaries' measure, and how many yards are in a fathom, and how many feet in a rod.

BugBear


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## RogerP (22 Sep 2015)

For years I worked at schools. 9 times out of 10 if you asked a boy how tall he was he'd reply in feet and inches. Yet these kids had only ever been taught metric. :? I suppose "nearly 6 feet" sounds a lot better than 1.80 meters


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## DTR (22 Sep 2015)

bugbear":28d2gk45 said:


> Anybody trying to convince themselves of the simplicity of the imperial system might want to look up how to interconvert mass between troy, avoirdupois, and apothecaries' measure, and how many yards are in a fathom, and how many feet in a rod.
> 
> BugBear



Do those conversions come up often in woodworking?


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## MCB (22 Sep 2015)

DTR":3jfcmbvt said:


> bugbear":3jfcmbvt said:
> 
> 
> > Anybody trying to convince themselves of the simplicity of the imperial system might want to look up how to interconvert mass between troy, avoirdupois, and apothecaries' measure, and how many yards are in a fathom, and how many feet in a rod.
> ...



What does come up in Woodworking is the need to find the centre of something and to my knowledge, centre rules are only available in inches and NOT in centimetres.

A centre rule is one with zero in the centre and markings increasing both to the right and to the left.

MC


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## DTR (22 Sep 2015)

I never knew such things existed!


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## Jacob (22 Sep 2015)

DTR":3qcqy8gc said:


> I never knew such things existed!


Nor me.
Centre (or any other division within reason) is very easy to find with dividers, or a marking gauge for centres alone

This should help BB http://gwydir.demon.co.uk/jo/units/length.htm


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## Sporky McGuffin (22 Sep 2015)

Jacob":1o8x2v31 said:


> It wasn't "designed" it evolved out of the needs of people working away at real things.



It was based on those units (English Units), but the Imperial system was most certainly designed, and was codified in the 1824 Weights And Measures act.



MCB":1o8x2v31 said:


> For example one gallon of pure water at 4 degrees centigrade has a mass of ten pounds



[pedant] Surely a _weight_ of ten pounds? [/pedant] 



MCB":1o8x2v31 said:


> What does come up in Woodworking is the need to find the centre of something and to my knowledge, centre rules are only available in inches and NOT in centimetres.



I've got a couple of plastic ones - I did find a steel one but only available in Oz. Though a quick Google found these two in the US... possibly worth a group order?

http://www.geionline.com/rulers/center- ... red/1034a/
http://www.totaltools.com.au/toledo-sta ... gGUcpd0esQ


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## Jacob (22 Sep 2015)

Sporky McGuffin":cae6rs1z said:


> Jacob":cae6rs1z said:
> 
> 
> > It wasn't "designed" it evolved out of the needs of people working away at real things.
> ...


Rationalised in 1824 but the design was a lot older! Or did they introduce new units?


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## Sporky McGuffin (22 Sep 2015)

They changed some definitions - but you're right that the vast majority of units predated the act.

I get the 12 inches thing - as you say, lots of factors - but then there are other units which interrelate by factors of 14 or 16 or 22 - that's just cruel!

Clearly, though, it's possible to build successfully with either system.


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## bugbear (22 Sep 2015)

Jacob":1r21any6 said:


> This should help BB http://gwydir.demon.co.uk/jo/units/length.htm



Good grief - what a _mess_.

Of course, each unit makes sense (and is practical) to its specialist user/creator, but the interconversion becomes a worse rat's nest with every units added to the pile.

The sub-divisibility of 12 is (of course) excellent - so for fractions of an inch we use powers of two! :roll: 

BugBear


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## Sporky McGuffin (22 Sep 2015)

I say if we can't have the full SI system let's go furlong/firkin/fortnight as base units. A microfortnight is about 1.2 seconds so it's pretty practical too...


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## Jacob (22 Sep 2015)

Sporky McGuffin":j2pobiw6 said:


> They changed some definitions - but you're right that the vast majority of units predated the act.
> 
> I get the 12 inches thing - as you say, lots of factors - but then there are other units which interrelate by factors of 14 or 16 or 22 - that's just cruel!
> 
> Clearly, though, it's possible to build successfully with either system.


And there is the baker's dozen. 13 ish
I'm surprised base 20 went out of use - except for the score. Why is that? The french still have quatre vingt. Apparently some foreigners still count eggs in multiples of 20 instead of the more sensible dozen. I wonder what the hens think.


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## Jacob (22 Sep 2015)

bugbear":21kxtntf said:


> ...
> The sub-divisibility of 12 is (of course) excellent - so for fractions of an inch we use powers of two! :roll:
> 
> BugBear


It's half, and half of that, and half again. Very practical - 1/64" being about the limit of what you can distinguish with the naked eye.


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## MCB (23 Sep 2015)

Pedants should kindly note that the POUND is a unit of MASS

WEIGHT is a FORCE 

The weight of the same mass will vary across the Earth according to the value of “g”

Anybody who studied O-level physics will know all this and more.

With best wishes. 

MCB


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## Phil Pascoe (23 Sep 2015)

Pedants don't need to note it.


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## Sporky McGuffin (24 Sep 2015)

MCB":1ck84ruj said:


> Pedants should kindly note that the POUND is a unit of MASS



True pedants will know that "pound" can refer to pounds-mass _or_ pounds-force (the gravitational force on one avoirdupois pound-mass at the notional surface of the Earth). Anyone who did GCSE physics would know that.

I don't know if they used to skimp on that sort of thing at school in the distant past. They probably had to keep things simple because the pupils all had smallpox and bubonic plague...


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## bugbear (24 Sep 2015)

On the beautiful relatedness of units; 

1 litre is 1000 cubic centimetres.  
1 gallon is 277.42 cubic inches. :roll: 

BugBear


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## Angusdog (25 Sep 2015)

On the vague subject of "Ain't no substitute for cubes" etc, here's a video of a Top Fuel dragster's fuel injector: https://www.youtube.com/watch?v=xGTbQuhhluY

In metric or imperial, that's a lot of petrol (gas). <Note: Might be methanol>


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