The heavier member of our black plated double hook family, wound from 3 mm wire for equipment that needs real pulling force. At this size the anchor points matter as much as the spring, because the load the spring can apply will find any weakness in the bracket.
Force capacity rises steeply with wire diameter, so 3 mm covers duties where a 2 mm spring would be permanently over-extended.
At higher loads the hook root is where failure starts. The transition radius is formed as part of the coiling cycle.
Keeps the spring visually consistent with dark equipment finishes.
Check the bracket and pin as well as the spring when upgrading wire size. Most failures after an upgrade happen at the anchor rather than in the spring.
2 mm springs being stretched past their limit because the load was underestimated
Hooks straightening out under load on springs whose ends were bent rather than formed
Dimensional and load figures are set per order against your drawing or sample, so they are marked TBC rather than filled with catalogue numbers.
| Product Type | Tension Springs |
|---|---|
| Raw Material Options | Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire |
| Wire Diameter Range | 0.1-8 mm |
| Surface Treatment Options | Zinc plating, Nickel plating, Silver plating, Gold plating, Tin plating, Galvanizing in various colours, Dacromet, Black oxide, Phosphating |
| Standard | ISO, non-standard and OEM drawings |
| Processing Route | Material sourcing → Coiling and forming → Heat treatment → Surface treatment → Quality inspection → Packing → Shipping |
| Inspection Equipment | Grinding and shot peening machinery; Precision tensile strength testers; Magnetic powder flaw detectors |
| Packing | Plastic bags, cartons or pallets, or packing to your own specification |
| Payment Terms | L/C, T/T, D/A, D/P, Western Union, 30% deposit before production, 70% balance before shipment |
| Lead Time | 7-15 days after the order is confirmed |
| Minimum Order Quantity | Quoted per part — tell us your requirement (TBC) |
| Dimensions and Load Rating | Made to your drawing or sample (TBC per part) |
Every batch follows the same seven step route, with tensile testing and magnetic powder flaw detection carried out before packing.
Available in Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire, in wire from 0.1-8 mm, with any of our nine surface finishing routes. Geometry, end treatment and finish are all specified per order.
ISO 9001, SGS certificate and RoHS report (stated on the legacy site, certificates pending re-confirmation). Certificate copies are sent on request once re-confirmed.
Against the 2 mm version, this spring gives considerably more force at the same extension and needs a proportionally stronger mounting. Neither is a drop-in replacement for the other.
Tell us the load and the travel. If a 2 mm spring would have to be extended beyond its safe range to give that force, 3 mm is the answer.
Usually yes. A stronger spring will pull through a bracket that was sized for a lighter one.
Yes. The 2 and 3 mm parts are catalogue references, not the limits of what we can coil.
Send your drawing, dimensions or a sample. We will confirm the specification and come back with a price and a lead time.
