30-Hour Mainspring for Mechanical Clocks – Loop End (5/16″ x 0.015″ x 42″)

30 Hour Clock Mainspring 8 X 0.38 X 1067Mm – Loop end

This 30 hour clock mainspring 8 x 0.38 x 1067mm is a replacement power spring for compatible 30-hour mechanical clocks. It uses a loop end and measures 8mm / 5/16 inch wide, 0.38mm / 0.015 inch thick and 1067mm / 42 inches long.

The mainspring stores the energy that drives a mechanical clock after winding. Correct width, thickness, length and end style are essential because these dimensions affect whether the spring fits the barrel or movement and how much power it delivers.

This replacement is intended for repair and restoration where the original spring is broken, weakened or otherwise unsuitable for reuse. It is particularly useful for clockmakers and experienced restorers who can compare the original spring dimensions before installation.

Specifications

• Width: 8mm / 5/16 inch
• Thickness: 0.38mm / 0.015 inch
• Length: 1067mm / 42 inches
• End type: Loop end
• Application: Compatible 30-hour mechanical clocks

Important

Please measure the original mainspring carefully before ordering. Width, thickness, length and end style must all be compatible. Mainsprings are under significant tension and should be installed with appropriate clock-repair tools and experience.

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