How to tighten confirmat screws in wall bar rungs

The rungs of wooden wall bars are held in the upright beams by confirmat screws – thick furniture screws that you drive into the end of each rung. They are what stops a rung from turning. This guide shows how to tighten them with the key without rounding out the socket in the head, snapping the screw or stripping the thread in the wood.

This guide supplements the assembly instructions. Always check the number of screws and the assembly order in the instructions for your model.

The essentials in brief

• 🔧 Use only the 4 mm hex key from the kit. No screwdriver drill, no power drill.
• Push the key all the way into the socket, straight in line with the screw.
• First drive all the screws in until the head sits flat, then tighten them one by one.
• Head seated and resistance clearly rising – a quarter turn at most, then stop.
• Key slipping or resistance suddenly gone – stop turning.

What is in the kit

A rung is a round beech bar with holes pre-drilled in its ends. Through the hole in the upright beam you drive a confirmat screw into it – a wood screw with a flat, round cylindrical head and a 4 mm hex socket (called the rung screw in the instructions). The holes are already drilled – you do not drill anything.

A confirmat screw has a thick, wide thread that cuts into the wood. It holds very firmly, but the thread in the wood can be stripped if you overtighten it. The screw then just spins in place and the rung starts to turn.

How tight is tight enough

Moderate hand force is all it takes: the screw head should seat against the beam, and from there you tighten only another quarter turn. That is about 4–5 Nm – roughly the same as pressing with your fingers with a force of 4–5 kg on the end of the key, 10 cm from the screw axis.

Where does this figure come from? A study by Poznań University of Life Sciences and Poznań University of Technology (2026) measured the torque at which the thread of 7 × 50 mm confirmat screws strips in the end grain of pine: on average at about 8 Nm, with the weakest joints failing at just 6 Nm. The authors recommend not exceeding 4 Nm. Beech is harder than pine, so the safety margin is larger – but the rule is the same: firm, but never forced.

Tightening step by step

You will need: the 4 mm hex key from the kit (or your own 4 mm L-shaped key) and a cloth.

Step 1. Key all the way in

• Check that there are no wood chips or paint in the socket of the head – clean it if necessary.
• Push the key all the way in and hold it straight in line with the screw, not at an angle.
• A key pushed in only halfway or at an angle is the most common cause of a rounded-out socket.

Step 2. Screw in without force

• For the first 3–4 turns the screw should go in easily and straight.
• Hard to turn from the start, or going in crooked? Take it out and screw it in again, straight into the hole. Do not force it.

Step 3. All of them first, then tighten

• Drive all the rung screws in until the heads sit flat – without tightening yet.
• Check that the frame is straight and the rungs are fully seated in the beams.
• Only now tighten the screws one by one.

Step 4. Hold the key by the short arm

• L-shaped key: long end in the socket, turn it by the short arm. Little leverage = hard to overdo it.
• Do not extend the key with a pipe and do not hit it.

Step 5. Head seated + a quarter turn

• Turn until the head seats against the beam and the resistance clearly rises.
• Tighten a quarter turn at most. Done.
• Check by hand: the rung must not turn.

Step 6. Stop signals

• The key slips in the socket – stop, push the key all the way in and press in line with the screw. If the socket is already rounded out, replace the screw with a new one.
• Resistance suddenly gone, the screw turns easily – the thread in the wood is stripped. Stop turning – see “A rung turns” below.
• You hear the wood crack – stop and check the beam and the rung.

Step 7. Check after 10 days

• After 10 days, and then every 10 days, check that the rungs do not turn and have no play.
• Rung sits firmly? Do not tighten it “just in case” – every extra tightening weakens the thread in the wood.
• Screw loose – tighten it as in step 5.

A rung turns – what to do

1. Remove the confirmat screws from both ends of the rung.
2. Pour a little glue into the hole in the end of the rung – any ordinary glue will do: wood, paper or universal – or insert a toothpick or a match with glue (without the head) and break off the protruding end.
3. Wait until the glue is dry (see the drying time on the glue packaging).
4. Drive the confirmat screw back in – step by step as above.

Didn’t help, or the wood has cracked? Do not use the wall bars and write to us – we will send you a spare part.

Most common mistakes

• A screwdriver drill or power drill instead of the key.
• Key pushed in only halfway or at an angle – rounded-out socket.
• Tightening “as hard as you can” – stripped thread and a turning rung.
• Extending the key with a pipe.
• Retightening every 10 days “just to be safe”, even though the rung sits firmly.
• Carrying on turning when the screw is already spinning in place.

Questions and answers

Can I use a screwdriver drill on the lowest setting?

No. Even a weak screwdriver drill easily exceeds the safe force, and you will not feel the moment the head seats. Tighten by hand with the key.

I lost the key from the kit – which one should I buy?

A 4 mm hex (Allen) key, ideally L-shaped. Available in any DIY store.

The screw is damaged – what can I replace it with?

Write to us – we will send you an original confirmat screw. Do not replace it with an ordinary wood screw.

How do I check that I tightened it correctly?

Grab the rung with both hands and try to turn it. It must not move. The screw head sits flat against the beam.

See also

• Mounting wall bars to the wall – which wall, which plugs
• Wooden wall bars
• User manual for wooden wall bars

Questions about mounting or spare parts? Write to us via the contact page. Source of the thread-stripping torque data: Zasuwik A., Sydor M., dataset “Thread-stripping torque of Confirmat screws”, Zenodo 2026, DOI 10.5281/zenodo.24045285 (CC BY 4.0).