Pocket Watch Database

E. Howard Watch Co. (Keystone) Balance Staffs

The delicate balance staff is one of the parts most frequently destroyed when a watch is dropped or sustains a forceful blow. The tiny pivots on each end of the balance staff are prone to bend and sheer under unreasonable force. When the balance staff is broken, it must be replaced by a staff matching the same dimensions as the original. If a factory-sized staff cannot be purchased, one must be fabricated using a watchmakers lathe.

When purchashing a replacement staff, pay attention to the avialable pivot sizes available. Many manufacturers also slightly modified the staff simensions, leading to some part number available in different variations (small/large collet, old/new style, short/long hub, etc). Keep this in mind when evaluating the avaialble staffs for a watch movement. It is recommended that the old staff be removed a measured prior to purchasing a new staff. Replacing a staff is a skilled operation requiring special tools. Please contacts a reputable watchmaker that specializes in antique watches if you are not equipped to replace a balance staff.

Movement Size   Part Number   Length (mm)   Balance Seat (mm)   Hairspring Seat (mm)   Roller Seat (mm)   Hub (mm)   Pivot Sizes   Image Purchase on eBay
18 76 (Long Style) 5.22 1.5 0.7 0.65 0.48 Buy Now
18 75 (Short Style) 4.85 1.5 0.7 0.65 0.48 Buy Now
16 338 5.42 Friction 0.6 1.05/.65 Friction Buy Now
16 341 5.45 1.3 0.95 0.66 0.46 Buy Now
If the E. Howard Watch Co. (Keystone) 341 staff is unavailable, there might be interchangeable alternatives. See the interchangeable list.
12 560 4 Friction 0.45 .76/.50 Friction Buy Now
12 561 4 1.2 0.73 .78/.50 0.33 Buy Now
10 799 3.55 Friction 0.46 .70/.42 Friction Buy Now
Data Source: Swartchild Balance Staff Charts and Company Material Catalogs
Pocket Watch Balance Staff Diagram