A Kilo of Nails

[richarta]

I was wondering how many nails there were in a kilo? Obviously, it depends on the size etc, so for example, how many 2" galvanised nails would one get in a Kilo?

 

[breezer]

why not weigh one and divide a kilo by the amount you now know?

(ideally you should weigh more than one to get an average)

 

[2scoops0406]

Wouldn't be very accurate, weigh a hundred instead

 

[AdamW]

Well, you can estimate it as such:

Your 2" nail. Let's say it has a shank diameter of 2mm, and let's approximate 2" to 50mm.

Rmembering your secondary school maths, the volume of the nail shank is the cross-sectional area multiplied by the length,

Shank volume = (pi * 1^2) * 50 = about 160mm^3

The head of the nail, let's say it is 6mm across and 1mm high.

Head volume = (pi * 3^2) * 1 = about 30mm^3

So the total volume of one nail is 190 cubic mm.

The density of a high-carbon steel is about 7850 kg per cubic metre. Thus one kilogram of steel has a volume of 1/7850 of a cubic metre.

To convert cubic metres to cubic mm, multiply by 1000 3 times:

(1/7850) * 1000^3 = 127,000 mm^3

So, one nail has a volume of 190 cubic mm. Our kilogram of nails has a total volume of 127000 cubic mm. Let's do some more arithmetic:

127000/190 = about 670 nails.

So, a kilogram of the arbitrary 2" nails I just invented, consists of 670 nails.

 

[2scoops0406]

Yeah, very good, weigh a 100, do the maths, will still be more accurate. nails are not uniform in any way shape or form.

 

[AdamW]

Ah, but you see, I am an analyst. This means that I make a list of educated assumptions and then work to these.

Why should I have to change my answer because real nails aren't as perfect as my nail volume/mass model? Real-world stuff like weighing things is what I get the engineers to do

 

[2scoops0406]

I work in IT, I have to deal with your sort every day

 

[richarta]

127000/190 = about 670 nails.

So, a kilogram of the arbitrary 2" nails I just invented, consists of 670 nails.

That approximation will do me - since I don't have 100 nails to weigh!

Thanks

Tim

 

[AdamW]

If you did have 100 nails to weigh, they would weigh 149 grammes

 

[oilman]

......nails are not uniform in any way shape or form.

Well if you get out of IT and into the real world, you might be surprised at how uniform mass-produced items are.

 

[AnonymousImport]

Come on Guys it made me smile, but there must be people out there that do need expert advice.

 

[mildmanneredjanitor]

Well, you can estimate it as such:

Your 2" nail. Let's say it has a shank diameter of 2mm, and let's approximate 2" to 50mm.

Rmembering your secondary school maths, the volume of the nail shank is the cross-sectional area multiplied by the length,

Shank volume = (pi * 1^2) * 50 = about 160mm^3

The head of the nail, let's say it is 6mm across and 1mm high.

Head volume = (pi * 3^2) * 1 = about 30mm^3

So the total volume of one nail is 190 cubic mm.

The density of a high-carbon steel is about 7850 kg per cubic metre. Thus one kilogram of steel has a volume of 1/7850 of a cubic metre.

To convert cubic metres to cubic mm, multiply by 1000 3 times:

(1/7850) * 1000^3 = 127,000 mm^3

So, one nail has a volume of 190 cubic mm. Our kilogram of nails has a total volume of 127000 cubic mm. Let's do some more arithmetic:

127000/190 = about 670 nails.

So, a kilogram of the arbitrary 2" nails I just invented, consists of 670 nails.

Adam,

great, can you help my daughter with her maths homework!!!

She's 11!

 

[AdamW]

can you help my daughter with her maths homework!!!

She's 11!

To be honest I would probably be rubbish at Year 7 maths, I never got good at it until GCSE so long division passed me by completel!

But I have a Physics degree now so I guess that could count for lost time

If there are any homework questions she is stuck on that you can't get your head round, I am sure people here would love to have a go!

 

[Handyman]

Excellent! Best posting I've read this month.

 

[glocko]

But I have a Physics degree now so I guess that could count for lost time

Don't fall for the hype guys, these Physicy people just sling in a constant when their sums don't add up, Avogadro...what's he all about then???

Best way to see if your weighed nails are a bargain is to look at the bag, if there's loads and not much cash...it's a good deal!!!

Glocko the tightwad