Manufacturing accuracy and limit deviation of spiral springs

6.3 Manufacturing accuracy and limit deviation of hot-rolled cylindrical spiral springs

Table 12-2-34

Project	Spring manufacturing accuracy and limit deviation
Limit deviation of height at specified load△H/mm	The minimum calculated deformation (mm) at a specified height of ± [1.5mm ± x3%] should be 1% of the free height
Ultimate deviation of load at specified height △ P/N	+Calculate deformation (m) at a specified height of [1.5mm x 3%] x spring stiffness (NVmm) [1.5mm+calculated deformation (m) x3% at specified height] The minimum value should be 1% of the free height
Limit deviation of spring stiffness △ P’/N*mm^-1	10% of spring stiffness P ‘
Limit deviation of spring outer diameter D₂ or inner diameter D_{1 △ D/mm}	Free height H₀	≤250	>250-500	>500
	Limit deviation _{△ D}	±0.01D Min ± 1.5	±0.015D Min ± 1.5	Provisions of the agreement between the supply and demand parties
The limit deviation of the free height H₀(length) of the spring/mm	± 2% of free height (length) H₀	When the spring has characteristic requirements, the free height is used as a reference
Limit deviation of total number of turns/mm	Compression Spring		Tension Spring
	±1/4		Agreement requirements between supply and demand parties
Perpendicularity of the axis line of the spring to the two end faces during leveling or grinding at both ends/mm	Common cases	Special Cases
	0.05H₀	0.02H₀
Limit deviation of straightness	Not exceeding half of the vertical tolerance