Building or repairing a quartz clock
A quartz clock movement is the small box behind the dial that turns the hands. Replacing a broken movement or turning a plate, wood slice, vinyl record or piece of art into a clock is easy – if you choose three things correctly: the shaft length, the hand lengths and the torque.
1. Shaft length
The threaded shaft passes through a hole in the dial and is held by a washer and hex nut on the front. The threaded portion must be longer than the dial is thick, with about 1.5 mm spare for the washer and nut. Suppliers usually sell movements by the maximum dial thickness they accept – for example 1/8", 1/4" or 1/2". Measure your dial with calipers and include any veneer, sticker or glass.
Required max dial thickness ≥ dial thickness + ~1.5 mm
2. Hand lengths
The minute hand should just reach the minute markers or the inside edge of the numbers; the hour hand is usually about 70 % of the minute hand and stops short of the numbers. The second hand is typically as long as or slightly longer than the minute hand.
| Dial diameter | Minute hand | Hour hand | Movement |
|---|
| 20 cm (8 in) | ≈ 8.5 cm | ≈ 6 cm | Standard |
| 30 cm (12 in) | ≈ 12.5 cm | ≈ 9 cm | Standard |
| 40 cm (16 in) | ≈ 17 cm | ≈ 12 cm | High torque recommended |
| 60 cm (24 in) | ≈ 25 cm | ≈ 18 cm | High torque |
3. Torque
Standard quartz movements are designed for light hands up to about 15 – 18 cm (6 – 7 in). Longer or heavier hands make the motor struggle, especially between 6 and 12 o'clock when the minute hand moves upward – the clock loses time or stops. High-torque movements, usually powered by a C cell, handle hands up to roughly 30 cm (12 in) or more.
Other choices
- Silent sweep vs ticking: sweep movements glide silently – ideal for bedrooms and offices.
- Radio-controlled movements set themselves from a time signal (DCF77, MSF, WWVB) and adjust for daylight saving.
- Pendulum and chime movements add a decorative pendulum or Westminster chimes.
- Outdoor clocks need sealed, weather-resistant movements and UV-stable hands.
Assembly steps
- Drill an 8 – 9 mm hole at the exact center of the dial.
- Fit the rubber washer, push the shaft through and tighten the brass washer and nut.
- Press on the hour hand at 12, then the minute hand at 12, then screw or press on the second hand.
- Check that the hands don't touch each other or the dial, then set the time with the knob on the back.
Frequently asked questions
What size clock movement do I need?
Measure the dial thickness and choose a movement whose maximum dial thickness is at least 1.5 mm more.
How long should clock hands be?
The minute hand should reach the minute markers – roughly 42 % of the dial diameter – and the hour hand about 70 % of the minute hand.
When do I need a high-torque clock movement?
For minute hands longer than about 15 – 18 cm (6 – 7 in) or for heavy decorative hands.
Why does my new clock stop between 6 and 12?
The hands are too heavy for the movement. Use lighter hands or a high-torque movement.
What size hole do I drill for a clock movement?
About 8 – 9 mm (5/16" to 11/32") for most standard threaded shafts.
About HandSpan
HandSpan is an independent, free calculator for building or repairing wall clocks with quartz clock movements and hands. Shaft sizes and torque limits are typical values; check the specifications of the kit you buy. We are not affiliated with any clock parts supplier.
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The methodology combines widely published engineering rules of thumb, manufacturer data sheets and the electrical code practices that installers use every day. We review the assumptions regularly and update the calculator when typical product specifications change.
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Last updated: October 28, 2026
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