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Old 4th February 2006, 22:33   #1
jat
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Default Just a thought - Units of measurement

I have observed that most of us here are using the FPS system of units. Also most of us have studied in India. Which means that we have studied using MKS or SI units in our school and colleges. So we are supposed to be comfortable with MKS or SI units (except oldies who have studied with FPS system). Any particular reason for it?

Why I have mentioned it because it can lead to some errors sometimes. For example in FPS system when we are measuring BHP, 1 HP = 746 W while in MKS system 1 HP (units used in PS) = 735.5 W. If we use the units KW as used in many countries, there is going to be no confusion.

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Old 5th February 2006, 22:30   #2
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In India, officially everyone should use kW and Nm. The funny thing is that often people quote power in BHP yet torque in Nm!

In USA and UK, they still use mile/bhp/lb-ft

Rest of Europe use SI.
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Old 5th February 2006, 22:39   #3
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ya as basak said...almost all the ad's of cars and bikes...and even automobile magazines use BHP for power. They are the ones who should change first which in turn will gradually lead to everyone using KW as standard units.
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Old 6th February 2006, 10:25   #4
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Quote:
Originally Posted by marinegopi
..and even automobile magazines use BHP for power. They are the ones who should change first which in turn will gradually lead to everyone using KW as standard units.
Exactly!

We are familiar with the specs of cars in the units that the magazines / websites provide. I am an MKS kinda guy, but i am lost if someone tells me 230PS (well i would be if the conversion wasnt so close!)

However, figures for torque, power etc dont really have the tangibility of something like 0-60mph, which most people know is 0-96km since they need to relate a enzo's 0-60 with their e-zens.... and the likes.

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Old 9th February 2006, 15:23   #5
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Actually, the main trouble-makers are the Americans who still use MPH (in lieu of KM/H) and Oz (in lieu of ML). We can pinpoint many instances of such American egotism in our day-to-day life.

PS : I'm not a die-hard Anti-American socialist.
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Old 9th February 2006, 19:26   #6
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Quote:
Originally Posted by mithun

PS : I'm not a die-hard Anti-American socialist.
hehe..but i am!

Anyways we Should follow the MKS/SI system here...
darn...my signature has a "mile" in it...(anti american..contradiction?)
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Old 10th February 2006, 05:55   #7
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Quote:
Originally Posted by mithun
Actually, the main trouble-makers are the Americans who still use MPH (in lieu of KM/H) and Oz (in lieu of ML).
Very true,

I am in a catch 22 in that sense.... i WANT to work in metric, EVERYONE does, but being in the US its difficult because -
1. If i talk in metric noone understands what im saying!
2. All the machines i use from rulers up to lathes and milling machines are in imperial!!

But thats slowly changing with more people realising that they are the only ones using imperial!! and ofcourse all the NC machines which can walk both sides of the line.

The other day, my friend who is very against the imperial system walked into a hardware store and asked for a metric hammer. Good one that!

cya
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Old 10th February 2006, 20:29   #8
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Post oz=ounces & lb=pounds!

Quote:
Originally Posted by Rehaan
Very true,

I am in a catch 22 in that sense.... i WANT to work in metric, EVERYONE does, but being in the US its difficult because -
1. If i talk in metric noone understands what im saying!
2. All the machines i use from rulers up to lathes and milling machines are in imperial!!

But thats slowly changing with more people realising that they are the only ones using imperial!! and ofcourse all the NC machines which can walk both sides of the line.

The other day, my friend who is very against the imperial system walked into a hardware store and asked for a metric hammer. Good one that!

cya
R
thats so true what you guys say.

its a PAIN re-learning measurement system's (especially for me) after you've crossed a certain age, and when you have had "metric" hammered into you for the first 25 years of your life..

i can live with mph but never with inches and gallons. however, the worst of it is the inches, lb & oz. i feel like an imbecile when anybody's using those measurements.

i generally have this bland dumb look on my face which worsens when the measurements get minute eg. 3/8th of an inch, 24'1/16" (DUH!?), 5lb 7oz.... it gets worse and worse....

also the US gallons are supposed to be different to the UK gallons. whatsup with that!

but as you say, they actually do list the metric measurements along-with the imperial ones nowadays on certain equipment so i guess there is some hope for this country yet..

haha.. would have loved to see the seller's reaction to the metric hammer!

Last edited by aah78 : 10th February 2006 at 20:43. Reason: modifying content
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Old 15th February 2006, 02:44   #9
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Quote:
Originally Posted by aah78
thats so true what you guys say.

its a PAIN re-learning measurement system's (especially for me) after you've crossed a certain age, and when you have had "metric" hammered into you for the first 25 years of your life..

i can live with mph but never with inches and gallons. however, the worst of it is the inches, lb & oz. i feel like an imbecile when anybody's using those measurements.

i generally have this bland dumb look on my face which worsens when the measurements get minute eg. 3/8th of an inch, 24'1/16" (DUH!?), 5lb 7oz.... it gets worse and worse....

also the US gallons are supposed to be different to the UK gallons. whatsup with that!

but as you say, they actually do list the metric measurements along-with the imperial ones nowadays on certain equipment so i guess there is some hope for this country yet..

haha.. would have loved to see the seller's reaction to the metric hammer!
You are not alone. It gets more confusing when the Uk guys use fulongs, hundredweights,quarter etc etc. Even the Britishers are at loss when using MKS system.

Once I was in UK and and came across a girl selling sweets. When queried she told us the price per quarter but when we asked her to tell us as per kg, she was at loss. So she asked people passing by to help her but everyone failed to convert quarter to kg. Soon there was a small crowd gathered but not a single person was able to help her.


I have seen ads in some Australian magazines and there they use KW for engine power. If we all resort to using MKS/SI units here, I am sure the manufacturers will be forced to use MKS/SI units. All we have to do is just stop blindly using cut paste techinque in our posts.


Using MKS/SI system is helpful as it is easier to convert from one form to another. Let us consider one example. Suppose a car uses power of around 50 KW (~68PS) to maintain a speed of 140 KpH and has an average of say 14 KpL. That means if car has run for 1 hour then it would have consumed 50KWH and 10 lts of fuel. Now you can compare the price of 50KWH of electricity and 10 lts of fuel easily.
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Old 28th March 2011, 11:52   #10
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Default Re: Somvarpet OTR 2010: Escape to Nature

Quote:
Originally Posted by fazalaliadil View Post
Its easy. Just an ordinary measuring tape. Don't bother I got it already.
Just measuring tape, won't that create parallax error? I am assuming you mean sidewall to sidewall.

Last edited by Samurai : 28th March 2011 at 16:58.
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Old 28th March 2011, 12:31   #11
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Default Re: Somvarpet OTR 2010: Escape to Nature

Quote:
Originally Posted by Samurai View Post
Just measuring tape, won't that create parallax error? I am assuming you mean sidewall to sidewall.
You will get parallax error even if you use the most sophisticated equipment in the world. Parallax depends on the viewing angle (line of sight) and not the measuring equipment.

Last edited by Samurai : 28th March 2011 at 16:59.
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Old 28th March 2011, 12:42   #12
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Default Re: Somvarpet OTR 2010: Escape to Nature

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Originally Posted by SPIKE ARRESTOR View Post
You will get parallax error even if you use the most sophisticated equipment in the world.
I thought Screw Gauge eliminated parallax error. Please explain how parallax error can happen in screw gauge?

Quote:
Originally Posted by SPIKE ARRESTOR View Post
Parallax depends on the viewing angle and not the measuring equipment.
Thanks Spike, what made you think I didn't know that? I admit I learned about parallax error 25 years back, but I still remember a thing or two from my school days.

Last edited by Samurai : 28th March 2011 at 16:59.
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Old 28th March 2011, 13:54   #13
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Default Re: Somvarpet OTR 2010: Escape to Nature

You have a high lift jack, right?
So you just touch one end of the jack to ground, and let the lifting lip touch the top of the wheel such that you are at center.
Then measure the "lift" of the jack with a tape.

Last edited by Samurai : 28th March 2011 at 16:59.
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Old 28th March 2011, 14:41   #14
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Default Re: Somvarpet OTR 2010: Escape to Nature

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Originally Posted by tsk1979 View Post
You have a high lift jack, right?
So you just touch one end of the jack to ground, and let the lifting lip touch the top of the wheel such that you are at center.
Then measure the "lift" of the jack with a tape.
Yes, that is a clever way of doing it.

Last edited by Samurai : 28th March 2011 at 16:59.
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Old 28th March 2011, 14:49   #15
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Talking Re: Somvarpet OTR 2010: Escape to Nature

Quote:
Originally Posted by Samurai View Post
Just measuring tape, won't that create parallax error?
Please explain how measuring with a tape will create parallax error? Does that mean tailors make clothes with parallax error built into it? Nah!

Quote:
Originally Posted by Samurai View Post
I thought Screw Gauge eliminated parallax error.
Screw gauge cannot eliminate parallax error, why do you think Screw gauge eliminated parallax error?


Quote:
Thanks Spike, what made you think I didn't know that? I admit I learned about parallax error 25 years back, but I still remember a thing or two from my school days.
Because I thought you did not know that. I guess you are referring to "Zero error" of measuring instruments

PS- Parallax - Wikipedia, the free encyclopedia

Last edited by Samurai : 28th March 2011 at 17:00.
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