Subject: Formula for spring constant?
From: (Old Nick)
Date: 12/08/03 11:36 GMT Daylight Time
Message-id: 3f38c1b4.18433483@localhost

On 03 Aug 2003 20:40:01 GMT, a (Dave Baker) wrote
something
......and in reply I say!:


PMFJI.

Can you parethn....pra... you know, put brackets in your formula? G
I tried applying it various ways and got crazy answers.

And do you mean dims in mm, but answer in lb/inch?

Thanks in advance.

With dimensions in mm.

Spring diameter (D) = mean diameter i.e. o/d minus wire thickness (or i/d
plus
wire thickness of course)

Number of working coils (N) = fully compressed length divided by wire
diameter
minus a further 1.7 (to allow for dead coils at each end)

(d) = Wire diameter

Spring rate in pounds/inch is

d^4 / D^3 / N * 60,000

I can't honestly see what could need parenthesising but anyway

Let spring be as follows:

o/d 34mm
wire diameter 4mm
compressed length 28mm

d = 4mm
D = 34-4 = 30mm
N = (28/4) minus 1.7 = 5.3

rate = 4^4 / 30^3 / 5.3 * 60000 --
rate = 256 / 27000 / 5.3 * 60000
=107 lbs/inch


Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
I'm not at all sure why women like men. We're argumentative, childish,
unsociable and extremely unappealing naked. I'm quite grateful they do though.