Spring End Types Explained — Closed, Ground and Open Ends
Quick answer: Compression springs commonly have open, closed, or closed-and-ground ends; closed and ground ends sit flat and square for the best stability, and closed ends typically add two inactive coils (total coils = active coils + 2).
By Gurudatta Trading Co., Mumbai · Updated 2026-09-29
Compression spring ends
| End type | Description | Effect |
| Open (not ground) | Coil ends left untouched | Total coils ≈ active coils; can be less stable |
| Closed (not ground) | End coil is turned in to touch the next coil | Typically total coils = active + 2 |
| Closed and ground | Closed ends, then ground flat | Sits square on a surface; best load alignment |
Extension and torsion spring ends
- Extension: machine hook, full loop, side hook or extended hook — hooks carry the highest stress, so hook type matters for life.
- Torsion: straight, bent or hooked legs, with legs positioned to suit the mounting.
Choose ends from how the spring is mounted and how squarely it must load. State your end type when you enquire, and see how to measure a spring to record the other details.
Need springs made to your specification?
Gurudatta Trading Co. (Mumbai, since 2000, ISO 9001:2015) manufactures compression, extension and torsion springs to drawing or sample. Use the free Spring Rate Calculator or message us on WhatsApp.
FAQs
What is a closed and ground spring end?
The end coil is closed against the next coil and then ground flat so the spring sits square on a surface.
How many extra coils do closed ends add?
Closed ends typically add two inactive coils, so total coils = active coils + 2.
Which spring end type is best?
Closed and ground ends give the best squareness and stability; open ends are simpler and cheaper where alignment is less critical.