• Upcoming updates
    Over the next couple of weeks we will be performing software updates on the forum. These will be completed in small steps as we upgrade individual software addons. You might occasionally see a maintenance message that will last a few minutes at most.

    If we anticipate an update will take more than a few minutes, we'll put up a notice with estimated time.

    Thank you!

Kundo pendulum weights - again

AndyDWA

Registered User
Dec 26, 2013
621
6
18
Western Australia
Country
Region
I recently purchased a square-dial Kundo standard for my mother-in-law and set about cleaning it up. I had to "straighten" the anchor pin to get it going but could barely get 180deg turn out of it.

The pendulum only weighed in at ~240g (~8.5oz), which I understand is at the low end of Kundo weights, as described by John Hubby. With this in mind, I attached a .0024" wire (I didn't have anything closer to .0025"). It now rotates 270deg, but the clock runs 50% slow. It takes 1.5 minutes (90 seconds) to complete 8 beats.

I assume, since I need to gain around 30 minutes per hour, that would mean: 30mins/4mins => .00075" extra thickness.

This would mean fitting the recommended .0032" to correct the rate but I assumed the book was incorrect, from earlier commentary.

Also, the weights are molded lead (soft), not steel. Have I weighed it wrong or is there something else I'm missing? (I should have weighed some of my others but hate messing with them when they're running)

I am also interested in some indication of date. The backplate features two holes to the lower and left of the winding arbor (they look like leftovers from external click models) and an isolated logo. I think it's plate 1389. It has the common pendulum lock, so I guess it's post-1954ish. Do the two holes make it older than my other, almost-identical, clock that doesn't feature those holes?

Thanks as always.

_MG_6939.JPG IMG_6941.JPG
 

shutterbug

Moderator
Staff member
NAWCC Member
Oct 19, 2005
49,469
2,925
113
North Carolina
Country
Region
I've found that .0032" works for most Kundo's. Your math is correct. Go for it.
 

KurtinSA

NAWCC Member
Nov 24, 2014
5,734
586
113
San Antonio, TX
Country
Region
I recently acquired a square-dialed standard sized Kundo. The pendulum weighed 8oz which I believe is essentially the correct weight. I was on the phone with Chris Nimon at The Horolovar Store a while back and we were discussing pendulums weights for a clock I was working on. He noted weights from some of the pendulums in the guide - #97 @ 7.8oz, #99 @ 7.9oz, #100 @ 8.1oz, #102 ranges from 7.3 to 7.8oz...these were weights that he had measured himself. I would say that 8.5oz is too heavy.

Kurt
 

AndyDWA

Registered User
Dec 26, 2013
621
6
18
Western Australia
Country
Region
Is that weights in the pendulum, or weights from the pendulum?

Even so, my figure would not have been accurate to the decimal point. I think I rounded up a little from what the scales actually said and was referencing another comment thread where three different weights were mentioned, with 8.5 being the lowest.

Still, at .0032", it lands right on the book recommendation so I'll probably swap the spring and see what happens.

Thanks.
 

KurtinSA

NAWCC Member
Nov 24, 2014
5,734
586
113
San Antonio, TX
Country
Region
I weighed the entire pendulum...unhooked from the lower block and put that on the scale. I bought a postal scale at the local store...says it's accurate to 0.1oz.

Kurt
 

Forum statistics

Threads
178,855
Messages
1,568,747
Members
54,001
Latest member
Tracy K
Encyclopedia Pages
909
Total wiki contributions
3,078
Last edit
E. Howard & Co. by Steven Thornberry