Calculate Mainspring Thickness | Horology

A properly sized mainspring will fill half of the available area in the barrel. It is easy to calculate the dimensions of the barrel.

Change the items in the yellow boxes and see the Results below.

Calculator

Mainspring Thickness

Barrel Measurements:

Inside Diameter of the Barrel:

Diameter of the Barrel Arbor:

Mainspring Length:

Results:

Needed Mainspring Thickness:

Formula:

T_MS =

x ( D_B² - D_A² )

2 x 4 x L_MS

where,

This calculator, provided by Horology - The Index, is one in a series of repair calculations.