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 →Compression Springs
Custom Hourglass / Concave Compression Springs
Compression springs with a narrower waist and wider end coils, specified by the full diameter profile, working heights and required axial loads.
- Specification
- Drawing and working requirement
- Dimensions
- Confirmed for the assembly
- Performance
- Specified at working positions
- Quotation
- Submit dimensions and quantity
About Custom Hourglass / Concave Compression Springs
An hourglass compression spring has a reduced coil diameter near the middle of its body. The waist and end coils need separate dimensions because a single outside diameter does not describe the shape. Start with the mating seats and any guide rod, then define the required loads at working heights. The name alone does not establish spring rate, available travel or resistance to buckling.
Key Design Characteristics
- Show both end diameters and the minimum waist diameter on the drawing.
- Check the complete body profile against the housing throughout compression.
- Define end seating and guidance rather than relying on the hourglass shape alone.
Choosing Between Related Designs
Use this page for a body that narrows toward the middle. A convex spring widens at the middle, while a conical spring tapers from one end to the other. Compare these shapes using the same installation envelope and load points.
Specification and Inspection Review
For inspection, agree which diameters are measured in the free state and how the spring is located during load testing. Include seating, permanent-set and cycling criteria if they are critical to the assembly.
Product Specification
What to Define for This Spring
Use these product-specific inputs to describe your requirement. Final dimensions, material and performance are confirmed against the drawing and operating conditions.
| Specification item | What to define |
|---|---|
| Diameter profile | End diameters, waist diameter and the location of each transition. |
| Height and travel | Free height, working heights and minimum permitted compressed height. |
| Load points | Required axial load and tolerance at each stated height. |
| Guide and seats | Guide-rod diameter, housing clearance and end-contact requirements. |
| Wire and duty | Wire size, material condition, temperature and cycling requirement. |
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
Review spring steel or stainless wire against the operating environment, waist geometry and required deflection.
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
Use the engineering guide for design support
Use the engineering library to review materials, sizing considerations and applicable standards for the custom design.
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.
Compare Designs
Related Spring Products
Use these alternatives when the available space, connection style, travel or force direction changes.
Compression Springs
Convex Compression Springs
Barrel-shaped compression springs with a wider middle and smaller end coils, reviewed against seat dimensions, housing clearance and working loads.
Compression Springs
Conical Compression Springs
A tapered compression spring for assemblies that need a changing diameter, improved stability, or a lower compressed package than a conventional straight coil can provide.
Compression Springs
Variable-Pitch / Progressive Compression Springs
Variable-pitch compression springs specified by a required load curve, with coil spacing and working travel reviewed together.
Product Questions
Hourglass / Concave Compression Springs FAQ
Does an hourglass shape automatically give a progressive rate?
No. The force curve depends on wire size, coil diameters, pitch and when coils become inactive. Specify the required force at working heights instead of assuming a curve from the shape.
Which diameter should I use for a guide rod?
Provide the smallest internal clearance and the intended guide arrangement. The complete spring profile and working movement must be checked against the rod.
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.