ATK303: Compression spring 12.7

Length 12.7, Diameter 10.4, Wire diam 0.81, Solid Len 3.5, Tension 2.16N/MM

  • Manufacturer: Various
  • Product ID: C2-2737-2M (Flexosprings version)

A 12.7mm long compression spring used in the Clinch (fire) button design.

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Indicative Pricing With Allowance for P&P

Springs are probably the most difficult and expensive things to source. This is a stock spring available from many different manufacturers (see below on what aspects are critical) and although they are not expensive you'll probably get hit hard for P&P.

Flexospring charge £8.63 for this spring + postage but they require a minimum order of £9+p&p, so you'll have to buy other stuff off them to complete your order. As an indicative price I've gone for £10 effectively for this spring.



Although these are commodity items you may struggle to find an exact duplicate unless you buy from flexospring. If you want to vary any of these dimensions these are the consequences.

  • Length 12.7mm - A bit longer or shorter is fine
  • Outer diameter 10.4mm - Do not go any wider. The cavity for the spring assumes this
  • Wire diameter 0.81mm - This affects the inner diameter which is also critical or the spring will catch
  • Inner diameter 8.78mm - You could drop this to 8.4mm at a push
  • Solid length 3.5mm - Shorter is fine, you could go as long as 4mm.
  • Tension 2.16Newtons per mm - Not so critical. This effects the feeling of pressure needed. I chose this pressure to give a nice strong but not too string operating force of around 15 Newtons. = 1.5Kg