The problem a double gate has to solve
A double gate has two leaves that meet in the middle. Usually one leaf, the active leaf, is opened for everyday use, while the other, the inactive leaf, stays closed most of the time and opens only when you need the full width, for example for a vehicle or a large delivery. A leaf hung from one post with nothing on its free edge can swing in the wind. The active leaf can latch to the inactive one, but the inactive leaf needs something to hold it firmly in place. That is what a drop rod or cane bolt does.
How a drop rod works
A drop rod is a vertical steel rod fixed to the inactive leaf by guides. When you lower the rod, it slides down through the guides and into a hole, sleeve or receiver in the ground, pinning the leaf at its bottom edge. Lifting the rod frees the leaf so it can swing. Many designs have a handle, a ring or a small hook at the top, and some have a spring or a latching position to keep the rod up while the gate is open.
The ground receiver can be a metal sleeve set in concrete, a plate with a hole, or a hole in a hard surface lined with a pipe. The sleeve keeps the hole from collapsing and gives the rod a firm place to land. Some installations use a receiver on a rail or sill instead of the ground, and top-mounted receivers on an overhead beam or arch also exist, which avoids the debris problem but is not always practical.
Cane bolts
A cane bolt is a close relative. It is an L-shaped or cane-shaped rod with a bent handle at the top. You lift it, and in many designs turn it so it rests on its own handle in a raised position, which keeps it from dropping while you open the gate. Lowered, it goes into the ground receiver. The two names are often used almost interchangeably, and what one seller calls a drop rod another may call a cane bolt. The practical difference is usually size and weight: cane bolts tend to be lighter, while drop rods are often heavier, with more substantial guides.
Choosing the right size
Match the rod to the gate. A larger, heavier leaf, or a gate that faces strong wind, needs a thicker rod and sturdier guides than a light garden gate. As a rough principle, the rod should be strong enough that it does not bend when the leaf is pushed, and the guides should be bolted through the frame, not merely screwed in. The longer the rod and the further the leaf extends, the more important it is to check the maker’s guidance.
Think about how often the leaf will be used. If the inactive leaf opens frequently, a slide bolt at the top and bottom or a heavier drop rod with a handy handle can be easier than a rod you must crouch to lift.
Installing a ground receiver
The receiver is the part that causes most trouble. A few points:
- Place it carefully. It must line up exactly with the rod when the leaf is closed and level. Mark the position with the gate closed, then dig and set it.
- Provide drainage. A receiver that fills with water or mud can freeze, jam or rust. Setting it on a bed of gravel with a drain path helps.
- Set it firmly. A sleeve in loose soil will tilt over time. Concrete around the sleeve, level with the surface, is usual, though the materials you use depend on the site.
- Keep it flush and safe. A receiver that sticks up can be a tripping hazard and can catch vehicle tires. Many are set flush, with a cover plate or cap.
- Call before you dig. Gas, power, water and communications lines can run through yards. Check with your local utility locating service before digging, as described in the article on utility locating.
If the soil moves with frost, the receiver can shift out of alignment. In cold climates, the effects of frost heave can be a reason a rod no longer drops cleanly in spring.
Common problems and fixes
- The rod will not drop all the way. Clear dirt, leaves, gravel or ice from the receiver. A gap between the rod end and the base of the hole can also mean the gate has sagged, or the receiver has shifted.
- The rod binds in the guides. Rust, paint or bent guides are the usual cause. Clean, lubricate if the maker recommends it, and straighten or replace worn guides.
- The leaf rattles. The rod is loose in its sleeve or guides. A sleeve of the right diameter reduces slop, and tightening the guides may help.
- The rod will not line up. If the leaf has sagged, fix the cause first; the article on gate bracing explains how a brace or cable kit keeps a gate square.
Security considerations
Mount the guides and handle where a person outside the gate cannot easily reach through and lift the rod. On a picket or slat gate, a handle on the outside face is an invitation. A small padlock hole or a padlock through the guide and rod can add a layer of resistance, as covered in the article on padlocks, hasps and lock boxes. As with any gate hardware, this is risk reduction and not a guarantee. Do not use this information to open a gate on someone else’s property.
Double gates and automatic openers
If you are thinking about automating a double gate, note that the leaf secured by a drop rod must be released before the opener moves it. Automatic gates need proper safety features, and installation is best left to qualified professionals who can set up releases, sensors and force limits correctly. Where an automatic gate has a manual release, any drop rod should be fitted so that it cannot trap someone or block the release.