- a fine, usually spiral, spring used for oscillating the balance of a timepiece.
Origin of hairspring
Also called balance spring.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for hairspring
If this is a balance pivot, be very careful to see that your balance is true and poised before putting on hairspring and roller.
Presume the existence of a vertical line through the center of hairspring and collet as shown at "A B" Fig. 9.
Hairspring concave or convex in form instead of perfectly level.8.
The complete balance and spring can be inserted and the pivots can be refinished without disturbing the roller or hairspring.
The hairspring should be removed and the pivots known to be straight and polished before testing.
- horology a very fine spiral spring in some timepieces, which, in combination with the balance wheel, controls the timekeeping