Length of 250g of 37 SWG (40 AWG) wire?

It's just possible a manufacturer may have date, like these people:

or

You did say "enamelled" so I ass-ume you mean magnet wire:

Alex Coleman wrote in news:Xns98D3EB2757ECE71F3M4@127.0.0.1:

Density of copper = 8.94 gm/cm3 (various sources give 8.92 to 8.96.)

I don't know what the weight of the enamelling is, but as copper is more dense than iron, I'll ignore it.

Cross section area = PI * r (in cm here) squared = 0.00022698 cm2.

Length is 27.964/0.00022698, so 123200 cm.

You might have to take the weight of the enamel into account with that thin wire, but I think a calculation might get close enough.

My wire tables say AWG 40 is 33,410 ft/lb.

So, for 250g =0.551155655 lb would be 18,414 ft = 5,600m, about 4.6x as long.

The reason for the discrepancy-- the diameter of AWG 40 is given as

Best regards, Spehro Pefhany

Spehro Pefhany wrote in news: snipped-for-privacy@4ax.com:

Or, to put it another way, how long is a piece of metal string? >:)

What with the differing vlues for density, the unknown thickness and weight of enamelling, and what may or may not be a confusion somewhere between radius and diameter, the room for error is large. The OP gives 0.17 mm as a diameter, but yours might be a radius, given a figure of 0.08. I've no idea which is right, but that half/double between the two values is suggestive.

Spehro Pefhany wrote in news: snipped-for-privacy@4ax.com:

So it is. I went looking. I don't know where the OP's value of 0.17 comes from, I just took it at face value.