Quick answer: A spade is a flat fork that slides under a binding post and clamps when the nut is tightened. Open shanks slip on without removing the nut and lift off again just as easily. Closed shanks need the nut off but cannot slide out. Choose by how often the cable changes, then tighten until the lug is firm rather than until the post complains.
The speaker sits four inches from a skirting board, the post faces the wall, and a banana plug will not go in straight. A spade solves that, then raises a second problem: which shape, and how hard to tighten it. Getting it wrong shows up months later as a channel that cuts out.
What a spade actually does
Speaker cable spades are pressure joints and nothing more. A spade holds two clean metal faces together under load, and everything else about the shape is about keeping that joint intact.
Clamp force, not surface area
A wide lug spreads pressure over more metal, which helps only if the nut can supply the force. A thin fork that bends as it is tightened loses that force again, so a rigid shank of modest width usually holds better than a large soft one.
Where the fork sits on the post
The lug should sit flat against the post face with its full fork engaged. If the fork straddles the threads and rests on the nut instead, the joint depends on the nut alone and works loose as the assembly cools and warms.
Open shank against closed shank
This is the decision most buyers actually face, and it is a service question more than an electrical one. Both clamp the same way once the nut is down.
| Spade type | Fitting the post | Holds under vibration | Removal for service |
|---|
| Open wide fork | Slides under a loose nut | Can creep sideways | Lifts off in seconds |
| Open narrow fork | Needs a clear post face | Grips a small post well | Lifts off in seconds |
| Closed ring shank | Nut must come off | Cannot slide out | Nut off, then lift |
| Insulated boot | Same as its metal body | Depends on the body | Cover must be peeled |
Stacking two lugs under one post
A single post asked to take two spades is a stack of three joints rather than one, and the nut now clamps through both lugs. It holds if the surfaces are flat and the nut has enough thread to bite, and it fails if either lug is soft enough to dish.
When stacking is acceptable
Stacking works for a permanent install where both cables leave in the same direction and nothing will be moved. It is a poor choice where one cable comes and goes, because the second lug loses clamping force every time the nut is loosened and re tightened.
Keeping the stack flat
Put the lug with the larger contact face against the post, keep both forks in line rather than at an angle, and check that at least a full turn of thread remains above the nut. If there is not, the stack is too thick for that post.
Torque without damage
Hand tight plus a small extra turn is enough on most binding posts. The aim is a joint that will not move when the cable is tugged gently, not a nut buried in the post. Hold the post body with a second hand so the terminal block takes no twist, and re check the nut after a week of use.
Re checking a joint after a month
A joint that felt firm at install goes slightly loose once the strands settle under pressure. Put a hand on each post after a few weeks of use and tighten only if the lug moves. A fine line of paint across the nut and the post turns that check into a glance rather than a decision.
Practical scenarios
- Wall hugging shelf: A narrow open fork slides in where a plug body cannot, and the cable can be dressed straight down without a bend at the post.
- Frequent swaps: Open shanks on both ends let a pair move between amplifiers in seconds, at the cost of checking the nuts afterwards.
- Permanent cabinet: Closed shanks on a post that will not be touched again remove any chance of the lug working sideways over the years.
- Two pairs on one terminal: Thin, rigid lugs stacked in line keep the joint flat, while thick soft lugs should be given their own post instead.
FAQ
Will a spade fit a spring clip terminal?
No. Spring clips take bare wire or a pin, because there is no threaded post to clamp a fork against. Twist the strands and keep them clear of the other clip.
Do spades need a washer?
Only if the post has a smooth face that the lug cannot bite. A star or split washer can help hold a stack, but it also adds a surface that can corrode, so use one only where the joint has proved unstable.
Can I re use a spade after removing it?
Yes if the fork is still flat and the crimp or screw is sound. A lug that has been bent open to fit a larger post should be replaced, because the clamp force it was made for is gone.
Next step
If the post is easier to reach than the wall, compare these with locking speaker connectors, look at banana plug ends for a straight push fit, and read the banana jack build notes before you commit a whole system to one shape.
See the matching cables and adapters
