Conical and Tapered Springs: Low Solid Height and Non-Linear Force by Design
A conical (tapered) compression spring has coils of progressively changing diameter. That simple change buys three properties a straight spring cannot match.
Three advantages
- Telescoping solid height. If each coil can nest inside the next, the spring compresses to nearly the height of one or two wire diameters — perfect where axial space is scarce.
- Buckling resistance. The wide base makes conical springs self-stabilizing without guides, even at higher slenderness.
- Progressive rate. Larger coils deflect first and bottom out gradually, so force rises progressively — useful for cushioning and vibration isolation.
Typical applications
Battery contacts (often combined with a flat spiral tip), push buttons, PCB grounding contacts, vibration mounts, firearm and tool mechanisms, and any assembly where a straight spring would buckle or not fit when compressed.
Design notes
- Specify large-end and small-end diameters, free length, and — as always — load at working height.
- Full telescoping requires each coil's OD to clear the next coil's ID; your manufacturer will check nesting from wire diameter and pitch.
- Rate is non-linear by nature. If you need a defined force at two heights, give both points rather than a single "rate."
- Grinding the large end is common; the small end often stays unground.
Cost and manufacturing
Conical springs run on the same CNC coilers as straight springs; cost is similar at moderate volumes. Setup is slightly longer, and very steep tapers may need special arbors. For battery and contact springs, we routinely combine conical geometry with gold- or nickel-plated finishes for conductivity. Send your envelope dimensions via the RFQ form for a fast feasibility check.
Frequently Asked Questions
Can every conical spring compress flat to one wire diameter?
Only if coil diameters and pitch allow full nesting. A shallow taper with thick wire cannot nest; ask for a nesting check if minimum solid height is the goal.
Are conical springs more expensive than cylindrical ones?
Marginally, due to setup; at production volumes the difference is usually within 5–10%. The assembly space they save often outweighs it.
How is spring rate defined for a conical spring?
It is progressive: initially low as large coils deflect, rising as coils bottom out. Specify loads at specific heights instead of one linear rate.