Applications
Where this spring style fits
Review best-fit uses, assembly constraints and situations where another spring style may be a better choice.
View application guidance →Torsion Springs
Custom Torsion Bar Springs
A straight or shaped bar that stores energy by twisting along its length, useful when rotary compliance is needed without a conventional helical coil.
- Typical configurations
- 27
- Wire diameter
- 0.3–4 mm
- Outside diameter
- 3.57–59.78 mm
- Free length
- 29.38–197.99 mm
About Custom Torsion Bar Springs
Torsion bars use the shaft itself as the spring element. Their behavior depends on bar length, cross-section, material and the way torque is introduced at each end. They are typically more dependent on end interfaces and overall system layout than small helical torsion springs.
Key Design Characteristics
- Active bar length directly influences angular stiffness.
- End splines, flats, arms or other interfaces must transfer torque without local slip or excessive stress concentration.
- Surface condition can be important because torsional fatigue begins at the outside surface.
- Packaging can be efficient when a long straight member fits the product better than a coil around a pivot.
What to Specify for a Custom Quote
- Bar diameter or cross-section and active torsion length
- Required torque versus angle
- End connection geometry and orientation
- Maximum angular travel and expected cycle life
- Material condition, heat treatment, surface requirements and quantity
Manufacturing Review
End features and the transition into the active bar need the same attention as the bar diameter. For high-cycle work, machining marks, decarburization and surface defects should be controlled alongside heat treatment.
Common Assembly Roles
- Long-axis rotary compliance
- Counterbalance systems
- Assemblies where a coil spring would be difficult to package
Product Data
Typical Spring Configurations
Use these data points to compare practical starting dimensions and material options. Final production specifications are confirmed against your drawing and working conditions.
| Model | Wire dia. | OD | ID | Free length | Rate | Material | Coils | Max load |
|---|---|---|---|---|---|---|---|---|
| SW-050-0070-0421-0727 | 0.5 mm | 7.02 mm | 6.02 mm | 42.1 mm | 0.54 | 301 Stainless Steel | 3.6 | 6.09 |
| SW-300-0502-0294-0777 | 3 mm | 50.15 mm | 44.15 mm | 29.38 mm | 2.725 | 65Mn Spring Steel | 2.8 | 22.92 |
| SW-400-0280-0916-0776 | 4 mm | 28.02 mm | 20.02 mm | 91.56 mm | 20.268 | Oil-Tempered Spring Wire (SWO) | 9 | 264.3 |
| SW-200-0404-0693-0763 | 2 mm | 40.45 mm | 36.45 mm | 69.33 mm | 0.524 | 65Mn Spring Steel | 5.3 | 4.22 |
| SW-080-0103-1415-0735 | 0.8 mm | 10.31 mm | 8.71 mm | 141.5 mm | 0.581 | Inconel X-750 | 8.1 | 19.06 |
| SW-030-0036-0668-0784 | 0.3 mm | 3.57 mm | 2.97 mm | 66.84 mm | 0.339 | Phosphor Bronze (QSn4-0.3) | 3.5 | 5.47 |
| SW-150-0288-1898-0728 | 1.5 mm | 28.77 mm | 25.77 mm | 189.78 mm | 0.366 | Carbon Spring Steel Wire (SWC) | 6.7 | 11.88 |
| SW-400-0598-1946-0790 | 4 mm | 59.78 mm | 51.78 mm | 194.56 mm | 1.743 | 316 Stainless Steel | 7.3 | 78.41 |
| SW-100-0150-1851-0799 | 1 mm | 15.03 mm | 13.03 mm | 185.11 mm | 1.49 | 60Si2MnA Spring Steel | 2.4 | 55.9 |
| SW-080-0101-0438-0780 | 0.8 mm | 10.14 mm | 8.54 mm | 43.75 mm | 0.274 | Phosphor Bronze (QSn4-0.3) | 9.4 | 1.96 |
| SW-050-0064-1525-0723 | 0.5 mm | 6.42 mm | 5.42 mm | 152.51 mm | 0.692 | Inconel X-750 | 4.3 | 25.05 |
| SW-050-0147-1980-0785 | 0.5 mm | 14.67 mm | 13.67 mm | 197.99 mm | 0.082 | 316 Stainless Steel | 2.3 | 3.46 |
| SW-030-0063-1761-0754 | 0.3 mm | 6.33 mm | 5.73 mm | 176.09 mm | 0.071 | 304 Stainless Steel | 4.5 | 3.49 |
| SW-150-0200-0793-0756 | 1.5 mm | 20.03 mm | 17.03 mm | 79.27 mm | 1.009 | 316 Stainless Steel | 6.8 | 17.35 |
| SW-050-0088-0477-0789 | 0.5 mm | 8.82 mm | 7.82 mm | 47.68 mm | 0.097 | 316 Stainless Steel | 9.6 | 0.54 |
| SW-100-0121-1578-0749 | 1 mm | 12.06 mm | 10.06 mm | 157.8 mm | 2.267 | Carbon Spring Steel Wire (SWC) | 3.2 | 96.15 |
| SW-030-0105-0612-0770 | 0.3 mm | 10.46 mm | 9.86 mm | 61.17 mm | 0.011 | Carbon Spring Steel Wire (SWC) | 7.2 | 0.08 |
| SW-030-0049-1792-0734 | 0.3 mm | 4.87 mm | 4.27 mm | 179.25 mm | 0.082 | 304 Stainless Steel | 8.9 | 1.96 |
| SW-200-0184-0983-0772 | 2 mm | 18.37 mm | 14.37 mm | 98.33 mm | 10.421 | Beryllium Copper (QBe2) | 2.1 | 291.06 |
| SW-150-0138-1747-0762 | 1.5 mm | 13.82 mm | 10.82 mm | 174.7 mm | 6.881 | Music Wire (SWP-B) | 3.9 | 158.74 |
| SW-100-0155-1742-0724 | 1 mm | 15.47 mm | 13.47 mm | 174.22 mm | 0.372 | Music Wire (SWP-B) | 8.8 | 18.07 |
| SW-200-0351-1736-0783 | 2 mm | 35.07 mm | 31.07 mm | 173.55 mm | 0.277 | Beryllium Copper (QBe2) | 9.6 | 11.11 |
| SW-030-0105-0766-0733 | 0.3 mm | 10.48 mm | 9.88 mm | 76.62 mm | 0.013 | Phosphor Bronze (QSn4-0.3) | 3 | 0.18 |
| SW-050-0118-1058-0795 | 0.5 mm | 11.79 mm | 10.79 mm | 105.76 mm | 0.063 | 301 Stainless Steel | 5.9 | 1.43 |
| SW-030-0074-0583-0747 | 0.3 mm | 7.39 mm | 6.79 mm | 58.33 mm | 0.033 | Phosphor Bronze (QSn4-0.3) | 3.5 | 0.57 |
| SW-150-0274-1734-0753 | 1.5 mm | 27.38 mm | 24.38 mm | 173.45 mm | 0.448 | Carbon Spring Steel Wire (SWC) | 6.4 | 22.74 |
| SW-080-0111-1553-0731 | 0.8 mm | 11.13 mm | 9.53 mm | 155.29 mm | 0.45 | Carbon Spring Steel Wire (SWC) | 8.1 | 17.72 |
Rate: N/mm; maximum load: N. Dimensions are in millimeters.
Engineering Data
Typical Dimensions & Design Data
Use these data points to compare geometry, material and working parameters when defining your custom spring. Final values are reviewed and confirmed for the actual assembly before production.
| Configuration | Data type | Key parameters | Material / basis |
|---|---|---|---|
| Engineering Data 01 | Engineering Data |
|
Round/flat/profile wire as applicable |
| Engineering Data 02 | Manufacturing Range |
|
Carbon / stainless / alloy spring materials |
| Engineering Data 03 | Design Input |
|
Per application |
| Engineering Data 04 | Manufacturing Range |
|
Spring steels / stainless / alloys |
Design note: dimensions, force / torque, material, tolerances, fatigue life and compliance are finalized against your drawing and operating conditions during quotation.
Next Design Decisions
Next Steps for Your Spring Design
Once the spring style is selected, confirm how it works in the assembly, which material suits the environment, how it will be manufactured and which dimensions and performance points should be controlled on the drawing.
Materials
Choose the material for the environment
Alloy spring steels are common where high torsional strength and fatigue resistance are needed. Corrosion-resistant or specialty alloys may be required for exposed or elevated-temperature service.
Compare spring materials →Manufacturing
Plan prototype and production
Review forming, heat treatment, secondary operations, inspection and the path from first samples to repeat production.
View manufacturing capabilities →Engineering Data
Open matching engineering guides
Matching material and wire-diameter pages provide additional design data for material and size selection.
Open Spring Engineering Guide →Material Direction
Common Material Families to Review
The links below are selection guides, not a claim that every grade is suitable for every size or load.
Related Spring Design Guides
Review the design and measurement requirements for this spring family.
Engineering Support
Spring Engineering Guides
Use these guides to compare material, wire diameter and standard requirements before finalizing the product drawing.
Material data
Carbon Spring Steel Wire (SWC) Torsion Springs Engineering Data
5 matching torsion bar springs data rows are included in the category.
Material data
Phosphor Bronze (QSn4-0.3) Torsion Springs Engineering Data
4 matching torsion bar springs data rows are included in the category.
Material data
316 Stainless Steel Torsion Springs Engineering Data
4 matching torsion bar springs data rows are included in the category.
Wire diameter
0.3 mm Torsion Springs Engineering Data
6 matching torsion bar springs data rows are included in the category.
Wire diameter
0.8 mm Torsion Springs Engineering Data
3 matching torsion bar springs data rows are included in the category.
Wire diameter
2 mm Torsion Springs Engineering Data
3 matching torsion bar springs data rows are included in the category.
Compare Designs
Related Spring Products
Use these alternatives when the available space, connection style, travel or force direction changes.
Torsion Springs
Straight-Leg Torsion Springs
A torsion spring with simple straight arms for hinges, levers and pivots where both contact points can be defined directly from the coil axis.
Torsion Springs
Double-Leg Torsion Springs
A torsion spring with two working arms used to share rotary load across a wider mechanism or provide balanced return around a common pivot.
Torsion Springs
Hairpin Springs
An open U- or hairpin-shaped spring for shallow layouts where two arms flex around a curved center rather than around a tightly wound coil body.
Product Questions
Torsion Bar Springs FAQ
What determines torsion-bar stiffness?
Material shear modulus, active length and cross-section are the main factors. Shorter or larger-diameter bars are much stiffer.
Are the end connections part of the spring design?
Yes. Splines, flats, welded arms or other interfaces transfer the full torque and can become the limiting area if not designed with the bar.
RFQ
Send the Working Requirement
A drawing is ideal. If you do not have one yet, provide the dimensions, load or torque, travel, environment and expected quantity that matter in the assembly.
CustomSprings Engineering Catalog
Request This Spring
Send your dimensions, quantity and drawing for engineering review.