Posts from the ‘Clocks and Movements’ Category

Clock Inserts / Fit-Ups vs Movements…how are they different and how to install / use them

We have another blog post that tries to explain the difference between clock inserts, also called fit-ups and movements that tries to explain why they are so difficult to order the right ones. Fit-ups are the most difficult because the way they are sized is based on the bezel size, but people tend to size them by the size hole you drill to install them in.

Now, we have made a short video to help explain the differences, how they are sized, and how to install them.

As always, if you have questions, call or email and we will help you to pick the clock part that is right for your project.

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Clock Insert and Movement Sizing Guide and Clock Making F.A.Q.

Clock Insert and Movement Sizing Guide and Clock Making F.A.Q.

Industry standard for clock INSERTS/MOVEMENTS is the outside dimension of the bezel/rim of clock face.

To select the right size REPLACEMENT insert:

  1. Measure the size of the hole if inside of a thicker material. Such as a Waterford or Tiffany clock replacement or inserted in thick wood.
  2. To order the appropriate insert, look in the item descriptions for the HOLE SIZE and ensure that it is equal to or slightly less than the size you have.
  3. The FACE or dimension of the outer bezel is always larger than the mounting hole size. THIS IS HOW INSERTS ARE CATEGORIZED.
  4. In some instances you may need to ensure the hole size is appropriate size and outer bezel measurement will fit within clocks design (i.e. not covering applied images or carvings).

If you are looking for clock MOVEMENTS, these are commonly mounted on the backside of thinner materials (plywood) and the shaft is inserted from the backside through a hole just large enough but not too large to ensure the washer and nut will cover hole and hold movement in place.

The most relevant measurement for MOVEMENTS is the shaft length.

The shaft length is measured from the plastic housing to the very tip of the shaft. NOT the length of the threads.

The shaft length ordered should be longer than the material mounted to.

EXAMPLE: 1 1/4” movement fits 3/4” material (plywood).

At woodworkingparts.com we work every day with our customers to answer their questions and help them determine the apropirate item for their project.

Common Questions for Hobbyists:

1: How difficult is it to install a quartz movement?

It is surprisingly simple. Just drill a 3/8″ hole in front of your clock case, slide the movement shaft through the hole and secure in place by tightening 1 hex nut.


2: How do I know what shaft length to use?

The shaft of the movement must be 1/16″ to 1/8″ longer than the thickness of the mounting surface.


3: How do I know what clock hands to use?

There are 2 elements to consider – style and size. The style you choose is a matter of personal taste. Contemporary or Novelty clocks tend to look better with plain looking hands that do not distract from the overall design.

The size that you use is determined by the size of the clock dial or fare that you use. Most clock dials have a minute track that runs near the outside edge. The tip of the minute hand should be just above the minute track. If your clock dial does not have a minute track, then the minute hand should reach about halfway across the numbers or indicators.

Remember, the most important thing is what looks good to you. It is your design, it should reflect your taste.


4: Do I need to use a second hand?

Most quarts movements have the ability to run a second hand. It is your choice to use one or not. If you feel the step second motion would be a distraction then don’t use one. A special closed nut is available to cover the small hole showing when a second hand is not used.


5: Should I use a pre-assembled “fit-up” or a quartz movement with separate hands and dial?

Using a pre-assembled quartz clock fit-up is the easiest way to make a clock. The clock movement, hands, dial, lens and Bezel are pre-assembled and ready to be installed. All you have to do is make a clock case with the correct size hole cut into it. Just set the time, put in a battery and press into the precut hole in your clock case.

To use a quartz movement requires a little more planning, but is still fairly easy to do. If you choose to do this you have the flexibility of being able to se a standard time only movement, a pendulum movement, a chime movement or a variety of other possibilities. You can also choose from dozens of clock dials and over 40 styles of clock hands. If you decide to use a quartz movement with separate hands and dial, it is much easier to create a design that is truly unique.


6: Do I need any special tools to install a quartz clock movement?

No, you do not. All you really need is a well lighted work area and a small pair of pliers.


7: Can I replace a battery operated movement in a broken clock I have?

Yes you can, and it is not to difficult. The first step is to remove the old movement from your clock. Remove the clock hands first by gently pulling them off. Sometimes the minute hand is held in place by a cap nut. Just unscrew it and continue to remove the hands. The movement itself is normally held in place by a hex nut on the hand shaft, or it can “snap in” which means it is being held in place by little plastic “fingers”. Either unscrew the hex nut to remove or just pry away from the case until snaps free.

The next step is to determine the size of the movement you have. The most important dimension is the shaft length. If your movement was held in place by a hex nut, then you need to measure the height of the threaded portion of the shaft that the hex nut was mounted to. This is referred to as the threaded shaft length.If your movement was a “snap in”, then just measure the overall shaft length.

Now that you know the critical dimension of your movement, look in the movement section of our web site to find a movement that suits your needs and budget. Please remember that the old hands from your movement may not fit the new movement. Hour and minute hands are included free with movements, so pick out a pair when you order.


8: I need to replace or repair an electric “plug in” type of movement, can you help?

We do not sell electric movements or parts for their repair.
Please contact Empire Clock Co. at their web site “www.empireclock.com”.


9: I need to replace or repair a mechanical weight or spring driven movement, can you help?

We do not sell mechanical movements or parts for their repair.
Please contact Merritts at “www.merritts.com” or S. LaRose at “www.slarose.com”.


10: If I give you the brand and model number of my broken clock can you help me repair it?

Probably not. We deal only in the latest battery operated quartz movements. While it may be possible to use one of our movements to repair your clock, we have no way of telling because we can not reference the brand and model number of your clock to determine what you may need.


Quartz Clock Movements

A quartz clock is a clock that uses an electronic oscillator that is regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks are at least an order of magnitude more accurate than good mechanical clocks. Generally, some form of digital logic counts the cycles of this signal and provides a numeric time display, usually in units of hours, minutes, and seconds. Since the 1970s, they have become the most widely used timekeeping technology

Explanation

Chemically, quartz is a compound called silicon dioxide. When a crystal of quartz is properly cut and mounted, it can be made to vibrate, or oscillate, using an alternating electric current. The frequency at which the crystal oscillates is dependent on its shape and size, and the positions at which electrodes are placed on it. If the crystal is accurately shaped and positioned, it will oscillate at a desired frequency; in clocks and watches, the frequency is usually 32,768 Hz, as a crystal for this frequency is conveniently small, and as this frequency is a power of two and can easily be counted using a 15-bit binary digital counter. Once the circuit supplying power to the crystal counts that this number of oscillations have occurred, it increases the recorded time by one second. This property, of changing shape under an electric current, is known as piezoelectricity. Such crystals were once used in low-end phonograph cartridges: the movement of the stylus (needle) would flex a quartz crystal, which would produce a small voltage, which was amplified and played through speakers.

Many materials can be formed into plates that will resonate. However, since quartz can be directly driven (to flex) by an electric signal, no additional speaker or microphone is required.

Quartz has the further advantage that its size does not change much as temperature fluctuates. Fused quartz is often used for laboratory equipment that must not change shape along with the temperature, because a quartz plate’s resonance frequency, based on its size, will not significantly rise or fall. Similarly, a quartz clock will remain relatively accurate as the temperature changes.

Mechanism

In modern quartz clocks, the quartz crystal resonator is in the shape of a small tuning fork, laser-trimmed or precision lapped to vibrate at 32,768 Hz. This frequency is equal to 215 cycles per second. A power of 2 is chosen so a simple chain of digital divide-by-2 stages can derive the 1 Hz signal needed to drive the watch’s second hand.

In most clocks, the resonator is in a small can or flat package, about 4 mm long. The reason the 32,768 Hz resonator has become so common is due to a compromise between the large physical size of low frequency crystals for watches and the large current drain of high frequency crystals, which reduces the life of the watch battery. During the 1970s, the introduction of metal–oxide–semiconductor (MOS) integrated circuits allowed a 12-month battery life from a single coin cell when driving either a mechanical stepper motor, indexing the second hand (in a quartz analog watch), or a liquid crystal display (in an LCD digital watch). Light-emitting diode (LED) displays for watches have become rare due to their comparatively high battery consumption.

Accuracy

The relative stability of the resonator and its driving circuit is much better than its absolute accuracy. Standard-quality resonators of this type are warranted to have a long-term accuracy of about 6 parts per million at 31°C (87.8°F): that is, a typical quartz wristwatch will gain or lose less than a half second per day at body temperature.

If a quartz wristwatch is “rated” by measuring its timekeeping characteristics against an atomic clock’s time broadcast, to determine how much time the watch gains or loses per day, and adjustments are made to the circuitry to “regulate” the timekeeping, then the corrected time will easily be accurate within 10 seconds per year. Temperature compensation is usually also included in the electronic circuitry. This is more than adequate to perform celestial navigation.

Some premium clock designs self-rate and self-regulate. That is, rather than just counting vibrations, their computer program takes the simple count, and scales it using a ratio calculated between an epoch set at the factory, and the most recent time the clock was set. These clocks usually have special instructions for changing the battery (the counter must not be permitted to stop), and become more accurate as they grow older.

It is possible for a computerized clock to measure its temperature, and adjust for that as well. Both analog and digital temperature compensation have been used in high-end quartz watches.

Many inexpensive quartz watches use a technique known as inhibition compensation. The crystal is deliberately made to run somewhat fast, and the digital logic is programmed to skip a small number of crystal cycles at regular intervals such as 10 seconds or one minute. The advantage of this method is that after measuring the frequency of each chip with a precision timer at the factory, storing the number of pulses to suppress in a non-volatile memory register on the chip is less expensive than the older technique of trimming the quartz tuning fork frequency. In more expensive watches, thermal compensation can be implemented by varying the number of cycles to inhibit depending on the output from a temperature sensor.

Chronometers

Quartz chronometers designed as time standards often include a crystal oven, to keep the crystal at a constant temperature. Some self-rate and include “crystal farms,” so that the clock can take the average of a set of time measurements.

Quartz wristwatches are in high demand today as they are more accurate than their mechanical counterparts; they need neither winding nor much maintenance. Light-powered and motion-powered quartz watches represent two innovative types of timepieces. Light-powered quartz watches incorporate a solar cell that transforms the light into electricity. Motion-powered wristwatches have a tiny rotor spinning in response to motion and generating electricity.