• The NAWCC Museum and Library & Research Center will reopen starting Wednesday, January 6, 2021 as per Governor Wolf's reopening mandate.

Eureka Eureka clock running slow

William Miller

Registered User
NAWCC Fellow
NAWCC Life Member
NAWCC Member
Jul 5, 2010
9
0
1
I have an "Eureka Clock" that is running slow, about 10 seconds per minute. The advance pawl is advancing properly ( 1 tooth/revolution). The poising weights are screwed all the way in (none are missing). The balance spring appears to have the correct no. of turns (approx. 12 1/2) and is in the clamp as far as it will go without protruding from the end. Shortening the spring does not have effect of the timekeeping. The balance wheel rotates about 355 degrees , using a 1 1/2 volt "D" cell. All the wheels in the movement move freely.
Has anyone else encountered a similar problem, and if so how was it resolved? Or, does anyone have any thoughts on how to resolve the problem?
William Miller
 

John Hubby

Senior Administrator Emeritus
Staff member
NAWCC Star Fellow
NAWCC Life Member
Sep 7, 2000
12,289
230
63
The Woodlands, TX
Country
Region
I have an "Eureka Clock" that is running slow, about 10 seconds per minute. The advance pawl is advancing properly ( 1 tooth/revolution). The poising weights are screwed all the way in (none are missing). The balance spring appears to have the correct no. of turns (approx. 12 1/2) and is in the clamp as far as it will go without protruding from the end. Shortening the spring does not have effect of the timekeeping. The balance wheel rotates about 355 degrees , using a 1 1/2 volt "D" cell. All the wheels in the movement move freely.
Has anyone else encountered a similar problem, and if so how was it resolved? Or, does anyone have any thoughts on how to resolve the problem?
William Miller
William, I've encountered this same problem on a few Eurekas. My solution was to rotate the balance spring forward through the clamp far enough to bring the clock to time. There is no reason you have to be limited to placing that spring with no protrusion through the clamp; however you do need to be sure that the coils do not make contact with each other at any position of rotation of the balance.

On one clock I had to move the end of the balance spring almost 1-1/2 inches before it came into range that the regulator would control the time.

The only explanation I have for this is that the balance spring for some reason has weakened from its original strength.
 

Tinker Dwight

Registered User
Oct 11, 2010
13,666
72
0
Calif. USA
Others have noted problems after putting the hairspring
in the ultasonic.
Tinker Dwight