The crown will not screw back down

A screw-down crown does not simply push into the case. It threads onto a tube, a short metal collar fixed permanently into the case wall, and compresses a gasket inside that tube as it tightens. The tube is the vulnerable part: it is small, it is fixed into the case, and replacing one is a bench job that involves removing the movement.

Which is why the answer to "it will not screw down" is never "push harder".

Do this first, in order

1. Turn the crown counter-clockwise several times. You are undoing, not doing. If it was cross-threaded, this releases it.
2. Check the crown is fully in. Pull it gently outward and feel for the click positions, then push it all the way back until it sits flat against the case. A crown in a date or time setting position cannot catch its thread.
3. Press lightly inward and turn counter-clockwise until you feel a small drop or click. That is the start of the thread finding its own alignment. This is the step almost everybody skips.
4. Now turn clockwise, still pressing lightly. It should bite within a quarter turn and tighten smoothly.
5. Stop at firm resistance. Finger tight is the specification.

If it bites and tightens, you are done. Have the watch pressure tested if it went in water while the crown was open.

If it still will not catch

There are four realistic causes, in descending order of likelihood.

• Grit in the threads. Sand, dried soap, dried sunscreen or salt crystals. Hold the watch under clean, cool running fresh water with the crown open, turn the crown gently back and forth, dry it and try again. This fixes it more often than anything else, and it is the reason a watch that has been to the beach should be rinsed.
• A damaged thread on the crown. The crown is a replaceable part, and it is the part designed to fail first. A watchmaker will order one against the case reference.
• A bent or loose stem. If the crown wobbles noticeably, or turns without any winding sensation, the stem has probably worked loose from the movement or the crown has come unglued from the stem. Do not keep turning it: a stem that separates inside the tube is a much larger job.
• A damaged tube. Rare unless somebody has already forced it. This is the expensive one.

What never to do

• Do not use pliers, a rubber glove for extra grip, or any tool. Grip is not the problem; alignment is.
• Do not apply oil, grease or lubricant of your own choosing to the threads. Case gaskets use a specific silicone grease, and the wrong lubricant degrades the rubber.
• Do not keep trying "just once more". Cross-threading damage is cumulative and silent.
• Do not put the watch in water to test whether the seal is holding. That is not a test, it is a gamble with the movement.

What it costs to put right

A new crown and gasket fitted, with a pressure test afterwards, is usually a modest bench job in the region of $120 to $350 at an independent watchmaker, depending on whether the part is a generic or brand-only item. A tube replacement is more, because the movement has to come out. A brand service center will typically fold both into a full service. US figures are indicative and quoted before sales tax, which varies by state; outside the US, local bench rates, import duty on parts and whether the part can be obtained at all move the number a long way, so ask for the quote before agreeing.

Whatever the repair, insist on a water resistance test afterwards. A crown that turns nicely proves nothing about whether the gasket is sealing.

Stopping it happening again

Get into the habit of the counter-clockwise-first move every single time. It costs a second and it makes cross-threading nearly impossible. Rinse the watch in fresh water after the sea or a swimming pool, including around the crown. And replace the crown gasket at every service, not just when it fails: it is a consumable, like the gaskets described in our guide to what a water resistance rating really means.

If the watch is one you swim with, the annual pressure test is the cheapest insurance available. Our water resistance checker will tell you what your rating and crown type actually permit.