Adjusting The Pendulum

Posted: Tue Dec 14, 2010 10:43 am     Post subject: Adjusting The Pendulum

Can someone tell me which way I should wind the the pendulum on my Dufa grandfather clock to slow it down, please?

By being careless I managed to break the original suspension spring. Someone very kindly gave me another one but the trouble is it is slightly longer so I need to adjust the clock. It doesn't seem to make any difference whether I wind the pendulum up or down the clock still gains.

Posted: Tue Dec 14, 2010 2:30 pm     Post subject:

Raising the pendulum will normally make the movement run faster. Lowering the pendulum will make the movement run slower. For Hermle movements we sell, rotating the rating nut clockwise will lower the pendulum and make the movement run slower. Rotating the rating nut counter-clockwise will raise the bob and make the movement run faster.

I am curious if the longer suspension spring might be effecting timekeeping. I will admit, however, that my experience with mechanical movements is modestly general (at best). Keep checking back for other posts from our more experienced patrons to see if they may have further suggestions.

Posted: Tue Dec 14, 2010 7:14 pm     Post subject: Adjusting The Pendulum

Up until now the clock has always kept very good time although I always have to adjust it if I move it.

As the suspension spring is slightly longer I wound the screw at the bottom of the pendulum up slightly to compensate but the clock ran faster.

I then tried lowering it. I kept lowering it until it wouldn't go any farther but it still ran faster!

Could the fact that the original is made of brass with thin tin piece in the middle whilst the new one is made of a silver colour metal make any difference? I was thinking about weight?

Posted: Tue Dec 14, 2010 10:46 pm     Post subject:

I would say you need to get the proper sized suspension spring, and work from there. The color of the spring does not matter.

The longer suspension spring could be causing an error that the pendulum can not account for.

Timesavers.com has the suspensions springs in many sizes, take the original one, and select the closest sized one.

http://www.clock-keys.com/pdf/Categories/suspension%20springs.pdf

Posted: Wed Dec 15, 2010 10:30 am     Post subject:

Thank you Chris and amrad. I will look into that.

Posted: Wed Dec 15, 2010 9:03 pm     Post subject:

i would just add that the thickness of the new spring is probably greater than the original thus making the pendulum swing at a faster rate.

Posted: Thu Dec 16, 2010 1:37 pm     Post subject:

Thank you clokfxr, I did wonder if it was the weight rather than the length that was the problem.

Does anybody know where I can get spare parts in the UK?

Posted: Thu Dec 16, 2010 2:22 pm     Post subject:

Here you go.

http://www.m-p.co.uk/index.htm

Posted: Thu Dec 16, 2010 3:40 pm     Post subject:

cousins and h s walsh - google for their websites.

Posted: Mon Jan 24, 2011 11:51 am     Post subject: wall clocks

you can adjust the time of pendulum by adjusting the pendulum bob, which is the round object near the top of the pendulum. Raise the pendulum bob to make the pendulum move faster, and lower it to make the pendulum move slower.