VALUE Clock brass winding key choose size 4-8 or 3.25mm 4.25mm wind clocks keys

Brass clock winding key available in sizes 4 to 8, covering square arbor holes from 3.25mm to 4.25mm.

⭐ At a glance

📏 Square hole sizes 3.25mm–4.25mm (key sizes 4–8)

✅ Fits grandfather, mantel, carriage, lantern and standard wall clocks

📦 One key supplied per order — choose your size

✔️ New, brass construction

Specifications

• Type: Winding key
• Material: Brass
• Finish: Brass
• Compatible Product: Grandfather Clock, Mantel Clock, Carriage & Lantern Clocks, Standard Wall Clock

🔧 What it does & how to use

A winding key is used to wind the mainspring of a mechanical clock via its square winding arbor. Clock keys are sized by number (4 to 8), each corresponding to a specific square hole size between 3.25mm and 4.25mm — the right size gives a snug, secure grip on the arbor so it turns cleanly without slipping or rounding off the corners.

• Measure first: check the width of the square winding arbor on your clock (a small ruler or vernier calliper works well) to identify the correct hole size before ordering.
• Fit the key: push the key fully onto the arbor so it sits square and snug, not loose or forced.
• Wind slowly: turn in the winding direction with steady, even pressure — never force past resistance, as this can indicate the spring is fully wound.
• Remove carefully: lift the key straight off once winding is complete to avoid marking the arbor or clock face.

⚠️ Please check the exact square hole size of your clock's winding arbor before choosing a key — sizes 4 to 8 are close together (3.25mm–4.25mm), and a key that's even slightly wrong won't grip properly or may damage the arbor.