Spring Index
Spring index, abbreviated as C, a dimensionless number, is the ratio between the spring and wire diameter for a helical spring. This number tells how tight the springs coils are. All wire sizes have a limit to the coil diameter being formed, too small there can be damage to the material. A higher spring index has a smaller wire and a larger spring diameter. A lower spring index has a larger wire and a smaller spring diameter.
Spring Index formula |
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\( C = D \;/\; d \) (Spring Index) \( D = C \; d \) \( d = D \;/\; C \) |
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Symbol | English | Metric |
\( C \) = spring index | \( dimensionless \) | |
\( D \) = spring diameter | \( in \) | \( mm \) |
\( d \) = wire diameter | \( in \) | \( mm \) |
Spring Index formula |
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\( C = 2 \; r \;/\; d \) (Spring Index) \( r = C \; d \;/\; 2 \) \( d = 2 \; r \;/\; C \) |
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Symbol | English | Metric |
\( C \) = spring index | \( dimensionless \) | |
\( r \) = spring radius | \( in \) | \( mm \) |
\( d \) = wire diameter | \( in \) | \( mm \) |
Tags: Spring