Bi-metal Snap Disc

Producing Snap Discs

How snap discs are created

Since we’ve already covered how our bimetal is composed, if you missed it you can find the post here, it’s time to talk about how the discs are created to ensure they react to the proper temperatures. Give us a call for for more information or visit our online store to purchase.

All of the discs are designed around temperature rise.  Discs (and switches) are designated F or L to describe what they will do on temperature rise.  F are designed to close on rise and L to open on rise.  You’ll also see measurements, such as 3/4 or 1/2, which reference the diameter of the bimetal disc.

Heat Treating and Forming the Discs

The first step is to take our metal, which comes in a big coil, and stamp it into discs.  These small discs (blanks) are then heat treated and are formed to react to the customer’s desired temperature, as shown below.

Forming Snap Discs


Testing the Snap Discs

After we’ve formed the discs, we test them using oil baths to make sure that they will react at the correct temps. The discs are placed in a bath to determine what temperature they “snap” at. If the disc doesn’t snap, it gets sorted out of the pile. The discs that do snap at the desired temperature get labeled and passed onto assembly.

Snap Disc Oil Bath

Senasys designs and manufactures snap disc thermostat switches. Senasys switches are UL and CUL Recognized. The majority of our switches are made in the United States and our direct customer service would be happy to help you find the right switch for your application. Senasys snap disc thermostats are single pole, single throw, fixed thermostat which may be used in applications such as industrial and HVAC equipment.

For more information about our snap disc thermostats, visit our website or contact us!

Snap Disc Thermostats Purchase Snap Disc Thermostats Contact us about our snap disc thermostats


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    Temperature Switches
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