Guide
Fixed knot vs hinge joint fence: construction, rigidity and post spacing
Last updated
A fixed knot fence has continuous vertical stays locked to each line wire by a separate small wire, so it stays rigid between posts set wide apart. A hinge joint fence has short stays wrapped round the line wires, so each joint gives and springs back, and the posts must stand closer. SIMO Securon's Q-Knot™ is a fixed knot fence.
How is each fence built?
Both are woven wire fences: horizontal line wires and vertical stay wires, joined where they cross. The difference is the stay and the joint. The US standard for woven wire fence fabric, ASTM A116, describes the stay wires as “either wrapped around the line wire (hinge joint) or fixed with another separate wire to the line wire (continuous stay fixed knot joint)”.
| Fixed knot fence | Hinge joint fence | |
|---|---|---|
| The stays | One continuous wire from top to bottom | A separate short length of wire between each pair of line wires |
| The joint | A separate small wire wrapped round every crossing, locking stay and line wire together | The ends of each stay wrapped round the line wires |
| Also called | Knotted fence, locked joint (UK), continuous stay fixed knot (US) | Hinge knot, field fence, hinged joint (UK) |
| In SIMO Securon’s range | The Q-Knot fixed knot fence | Not made |
Which is more rigid?
The fixed knot fence. Its joints are locked and its stays run the full height, so the mesh keeps its shape. The UK Forestry Commission’s guide to forest fencing explains the difference: in hinged joint netting the joints “may be relatively easily slid along the horizontal wire, especially when new, to produce bigger holes”, and the netting “has a tendency to concertina vertically” when it is lifted over rising ground or hit. Locked joint (fixed knot) mesh has “continuous vertical wires that prevent the net from folding up like a concertina”.
A hinge joint is designed to flex: its makers describe it as giving under an animal’s impact and springing back. A fixed knot fence gets its give elsewhere. In SIMO Securon’s Q-Knot, the line wires are deep-crimped between the stays, so the fence absorbs a push and returns to shape while every crossing stays locked. See fixed knot fence for how the knot and crimp work.
How far apart are the posts?
Because it stays rigid, a fixed knot fence spans further between posts. A US Department of Agriculture specification for woven wire fences (USDA NRCS, Kentucky) sets the maximum spacing of line posts:
| Fence | Line posts, at most | Brace assemblies, at most |
|---|---|---|
| High tensile continuous stay fixed knot woven wire | 25 ft (7.6 m) | 660 ft (201 m) |
| Conventional low carbon hinge joint field fence | 14 ft (4.3 m) | 330 ft (101 m) |
The two fences in that specification differ in their wire as well as their joint: high tensile against low carbon. SIMO Securon’s fixed knot fence takes a post every 5 to 6 m in Alpha and every 5 m in Zeta Nova and Pi, set by the ground, the height and the animals, and every corner and gate post is braced. Conventional galvanised chain link needs one every 2.5 to 3 metres.
Which suits a long boundary?
Where animals push hard and the boundary is long, the locked crossings and continuous stays of a fixed knot fence keep the mesh from opening up between widely spaced posts. The Forestry Commission calls locked joint the “more expensive high specification”, made only in high tensile wire, and notes that it is preferred “especially in high risk locations”. A hinge joint fence costs less to buy and suits lighter duty with closer posts.
For a farm against nilgai (blue bull) and wild boar, SIMO Securon suggests a 6 ft Q-Knot fixed knot fence: see farm fencing. For all the fence names side by side, see types of fence, and for chain link, knotted fence vs chain link.
FAQ
Fixed knot and hinge joint questions
Is a hinge joint fence the same as a field fence?
Usually, yes. Field fence, hinge knot fence and woven wire field fence are names for the hinge joint fence: a woven wire fence whose stays are short lengths of wire wrapped round the line wires at each crossing.
Is a hinge joint fence cheaper than a fixed knot fence?
To buy, usually yes. The UK Forestry Commission describes hinge joint netting as cheaper than locked joint (its name for fixed knot), and the locked joint as the higher specification, made only in high tensile wire. A fixed knot fence needs fewer posts, which also counts in the cost of a long boundary.
Which needs fewer posts, fixed knot or hinge joint?
A fixed knot fence. A US Department of Agriculture specification allows line posts up to 25 ft (7.6 m) apart for high tensile fixed knot woven wire, against 14 ft (4.3 m) for conventional low carbon hinge joint field fence. SIMO Securon's fixed knot fence takes a post every 5 to 6 metres in Alpha.
Does SIMO Securon make hinge joint fence?
No. SIMO Securon makes the Q-Knot fixed knot fence, which keeps animals out, and the ZS-Knot™ 4 x 2 inch anti-climb knotted fence, which keeps people out, both with a knot at every crossing.
Sources
- ASTM A116-22: Metallic-Coated, Steel-Woven Wire Fence Fabric (opens in a new tab), ASTM International
- Practice specification, Fence (Code 382), woven wire, Kentucky (opens in a new tab), USDA Natural Resources Conservation Service
- Forest fencing, Technical Guide FCTG002 (opens in a new tab), Forestry Commission (UK)
- BS EN 10223-5:2012: Steel wire woven hinged joint and knotted mesh fencing (opens in a new tab), BSI
Talk to the SIMO Securon team
Call or WhatsApp us with your site type, location and boundary length, and we will come back with a recommendation.