a pivoted axle or shaft on which the balance is mounted.
Origin of balance staff
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for balance staff
Historical Examples of balance staff
The roller being fastened to the balance-staff, of course, turns just as the balance turns and with it the jewel-pin.Time Telling through the Ages
Harry Chase Brearley