How to Control Torsion Spring Leg Angle and Orientation

A torsion spring can appear correct from one direction and fail assembly when reversed or viewed from another end. Stable leg angle and orientation begin with a drawing that defines the viewing direction, reference leg and inspection condition. Machine compensation becomes meaningful only when the supplier and customer measure the same feature in the same way.

Define winding hand and the reference view

Identify the winding direction using a clear drawing view and an agreed convention. Mark the reference leg and show how the second leg is oriented relative to it. Include any offset, hook or bend in the legs rather than treating them as simple straight lines. An annotated three-dimensional view can help resolve ambiguity, but the controlled drawing remains the acceptance reference.

Specify free or loaded measurement

State whether the angle is measured with the spring unloaded or at a specified load or deflection. Define the supporting mandrel, seating method and contact points where relevant. A fixture that pushes a leg into position can hide a free-angle error. Separate geometric inspection from torque testing and document the required condition for each.

Control the wire and process route

Record wire grade, diameter, delivery condition and batch. Confirm the intended thermal processing route before approving as-formed geometry. Use the same production material for setup trials, because a substitute sample may recover differently after forming. Keep samples traceable through each stage so a change after processing is not mistakenly attributed to the forming program.

Check feed rotation and tool positions

Verify that wire feeding is repeatable and that forming tools are seated consistently. Check tool contact and the sequence that creates each leg. On equipment with controlled rotation, confirm the reference position and setup record. The article on choosing CNC spring forming machine axes is useful when evaluating whether the available motions suit the required leg geometry; axis count alone does not prove capability.

Separate coil body variation from leg variation

Measure body geometry and the reference leg before adjusting the second leg. If the coil seats differently from sample to sample, the apparent orientation can change even when a local leg bend is repeatable. Track body diameter, seating and leg angle as separate observations. The discussion of diameter and pitch variation during CNC coiling provides related diagnostic principles, although its primary subject is compression springs.

Use a repeatable inspection fixture

Locate the spring without forcing it into the target angle. Identify a consistent reference axis and measurement position along the leg. Check that multiple inspectors obtain comparable readings on the same samples. A simple go/no-go fixture can support production screening, while a measured angle helps diagnose drift. Keep an approved sample with the fixture and record its drawing revision.

Compare before and after thermal processing

Where stress relief or another approved treatment is part of production, measure identified samples before and after that step. Use the specified process rather than choosing a temperature from a generic guide. If geometry shifts consistently, review the forming allowance and treatment control together. Approve the final delivered condition, not only the shape immediately leaving the machine.

Approve a sequence of parts and save the setup

Inspect consecutive samples after startup and again during a representative run. Retain the program revision, tool positions, material identity, process route and measurement method. Jinchun's compact spring coiling machine for compression and torsion springs provides a relevant product enquiry route. Send the leg drawing and inspection fixture requirements so the proposed tooling can be assessed against the actual part.

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