The tape method, and mark the top of each slot. Everything about how to mark keyhole slots on wall surfaces comes down to that second point: a keyhole hangs from the narrow end, so the screw sits at the top of the slot, not the middle.
Mark the middle and the piece hangs low by half the slot's length — and on a run of shelves, inconsistently low.
The Houseland pine modules all hang on keyhole hangers, so getting this right once means every piece in a set lines up.
How to mark keyhole slots on wall surfaces: the tape method
- Lay the piece face down and stick a strip of masking tape across both hangers, pressed firmly.
- With a pencil, mark through the tape at the top of each keyhole slot — the narrow end the screw ends up in.
- Peel the tape off in one piece. It now carries the exact distance between the fixings.
- Stick the tape on the wall, level it with a spirit level, and adjust until the marks sit where you want the piece.
- Drill through the marks, remove the tape, fit the fixings.
It works because the measurement never has to be written down or transferred twice. Whatever error exists on the tape is the error on the piece, and there is no arithmetic to get wrong.
Use low-tack tape on a painted wall, and press it down only along the line rather than across its full width.
Why the top of the slot is the point
A keyhole is a round hole with a narrow slot running from it. The piece is lifted so the screw head passes through the round part, then dropped so the shank sits in the slot.
Wherever the shank stops is where the piece hangs, and that is the closed end of the slot — the top.
So the screw's centre must line up with the top of the slot, not the round opening and not the middle.
Get this wrong on both hangers and the piece simply hangs lower than planned. Get it wrong on one and the piece hangs crooked, which is the version that sends people back to the wall with filler.
How far to leave the screw proud
Enough for the head to clear the back of the piece and for the plate to slide behind it — usually about 3 mm (0.12 in), though it depends on the hanger.
Too tight and the piece will not seat; too loose and it stands off the wall and rocks.
The reliable way to set it: hang the piece, then take it off and turn the screw a quarter turn at a time until it seats snugly and lifts off cleanly.
On a hollow-wall anchor, check the anchor still grips after backing a screw out. Some self-drive types rely on the screw being fully home, which makes them a poor match for keyholes — a metal toggle or an expanding anchor is better.
On the Houseland pine modules the hanger sits in a recess, so the back plate is flush with the timber and the screw head has very little room to play with. That is typical of keyhole hangers generally, and it is why a quarter turn makes a visible difference where on a picture hook it would make none.
From the shop
Cube Wall Shelf Set, 6-Piece Rounded Pine Box and Ledge Wall Shelves
A rounded pine cube module set, 3.5 in deep with 0.6 in board, in sanded natural pine under a clear matte lacquer. Wall mounted on keyhole hangers, rated up to 5 kg (11 lb) per piece.
See the productOther methods, and how well they work
| Method | Works | Why |
|---|---|---|
| Masking tape transfer | Best | No arithmetic, no second measurement |
| Paper template from the box | Good | If supplied and printed to scale — check with a ruler |
| Measuring hanger centres | Fair | Works, but every reading is a chance to be out |
| Toothpaste or chalk on screw heads | Fair | Marks the round hole, not the slot top |
| Eyeballing the second hole | Poor | The classic cause of a second set of holes |
The toothpaste trick is popular and slightly wrong for keyholes: it marks where the opening is, so the piece then hangs low by the slot's length unless you allow for it.
Getting a run of shelves to line up
Set every piece from one line rather than from its neighbour. A row built piece to piece inherits every small error and drifts visibly by the fourth module.
Draw or tape a single level line across the whole wall first, then use the tape transfer for each piece against that line.
Decide which edge the line represents — usually the top edge of each piece, or the slot tops themselves — and keep it the same for every module.
For a staggered arrangement, use two or three parallel lines rather than freehanding the offsets. The consistency is what makes a staggered layout read as designed. The spacing side of that is covered in how far apart to hang a group.
When the piece will not seat
Screws too far out. The piece hangs but stands off the wall and rocks. Turn each screw in a quarter turn at a time.
Screws too far in. The head will not pass the opening. Half a turn out is usually all it needs.
One screw high. The piece hangs crooked. Do not compensate by turning screws in and out — the fix is a new hole for the offending fixing.
Anchor pulled proud. A self-drive anchor that has partly backed out sits above the wall surface and stops the piece sitting flat. Replace with a metal anchor.
Paint build-up. Old thick paint around the hole can hold a piece off. A quick scrape around the fixing solves it.
A few habits that save the second set of holes
Mark lightly. A heavy pencil line needs cleaning off, and cleaning marks a matte wall.
Drill both holes before fitting either fixing. It is much easier to adjust a mark than a plug already in the wall.
Test-hang the piece before doing anything else — no objects on it, no vase, nothing. An empty piece is easy to lift and easy to look at.
Check the level with the piece hanging, not just the marks. Keyholes have play, and a piece can sit a degree out even when both fixings are perfect.
Then check again the next day. Anchors settle slightly as they take load, and that is the moment a small tilt appears — the same point made in stopping a piece going crooked.
Keep the tape after hanging. Written on with the piece's name and stuck inside a cupboard door, it becomes the template for rehanging the same piece after a repaint, or in the next house, without measuring anything again.
What I would do
Masking tape across the hangers, pencil at the top of each slot, tape on the wall, level, drill.
It takes about two minutes per piece and it removes every step where a number has to be remembered, which is where the errors come from.
For a set, add one line across the wall first and work every piece to it. That single line is the difference between a run that looks fitted and a run that looks approximate.