Debug Hints

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SP14 Moon Phase Clock Trouble

Having a problem keeping the clock running. I have taken it apart twice and all appears to be well. It will run with an even tick from just a few minutes up to 2 hours or so. Appears to run well and all gears turn as expected without the escapement as the weight slowly drops. The clock doesn't stop abruptly, but gradually loses amplitude and slowly stops.

Currently I have 8.75 lb of BBs in the weight shell. I'm not sure what else to try. I've looked at and tried the debug hints, but nothing seems to help. When the clock does run, it seems to run well. My only thought at this time is to add an extension on the shell and add more weight, say maybe 10 lb?

I'd appreciate any thoughts and help. Thanks!

36 Views

pataran

5 days ago

I had a similar situation with a clock I made. In the end I fixed it by polishing the ends of the piano wire shafts, reaming the plastic housings a few .001 over the true diameter and applying light machine oil to each spot in the frame where the shafts turn.

Also make sure you have clearance end to end. Should be about 1/8” of space. The plastic gears aren’t metal and aren’t perfectly round and aligned. There needs to be clearance all around to account for movement.

Finally, just let it run a while and I bet it sorts itself out. After making those changes of course.

May 20, 2026

Desk Clock SP10 and SP11 - Do you sell parts kits for these?

I am interested in SP11, and am wondering if you sell a parts kits for this model? I purchased the kits for my other two wall clocks.

I actually found this for $48 dollars... does it include everything I need to build the clock? Board and parts? https://www.etsy.com/listing/1464560995/silent-shield-clock-controller?variation0=3431579134

Thanks! Steve

164 Views

Steve

May 20

Yes. The electronics and hardware parts kits are available at Silent Shield Clock Controller - Etsy

May 18, 2026

SB13 hands not moving

SP13 clock, the gears are all running well - been ticking away for 4 days now.

The problem is that the hands aren't moving - and I believe that gear 4a is not driving gear 4b through the friction spring.

I have checked 4b is locked properly to the arbour with the M3 screw, so it seems it is 4a freely rotating and not driving the arbour (and 4b) through the spring.

Any tips for debugging this specific issue? Thanks!

125 Views

Jason Stonier

May 20

Quick question for the group - my clock is running perfectly on 2.7kg (~6lbs) main weight, but I am sure it will run on a lot less. Is there an advantage one way or the other to using more or less weight? Pendulum is currently plus/minus 14 degrees of arc.

I designed my own weight shell to suit a large lead ingot I had in, so it's a bit of a mission to cut sections off the ingot to try it (would be easier with lead shot obviously).

Edited

May 1, 2026

Moon Dial Moving Too Fast

The rest of the clock seems to be working perfectly, but the moon dial is FLYING compared to how fast it should be going. Honestly, closer to a quarter turn each day. I haven't had the time to check, but I'm guessing that clutch set is too tight or maybe I have too strong a spring in it or something. Is it possible to have too strong or too weak of a pen spring? What are the optimal specs of the springs that should be used in the clutches? I've been using 0.5x5x20mm in the past without any noticeable trouble, so I never thought that they might be putting too much friction into the system. Now with adding the additional gears for the moon phase, it's made me think about that potential. I also have 0.3x4x25mm that I use for ratchet assembly.

Edit: After pulling things apart and taking a closer…

121 Views

Steve

May 01

The normal operation of the moon dial is powered by the hour hand gear. Two stages of gear reduction turns the moon dial with a 59 day cycle. The moon phase friction clutch passes through gear 5 where there is room for the spring. Gear 5 sits between gear 9 and the moon phase friction clutch. The moon dial sits between gear 6 and the front frame. There is a lot going on in a very small space.

If the moon phase is rotating too fast, then the moon phase friction clutch is slipping. That alone doesn't indicate if it is an issue with the friction clutch or the gears binding up.

The easiest way to debug this would be to remove all the gears except the central arbor and the gear 5/9 arbor. This allows you to only the gears of interest. Rotate gear 4 to move the minute hand while observing the rest of the gears. There should be minimal resistance if all the downstream gears move freely as intended. If there is any binding, then rotating gear 4 would need enough force to allow a friction clutch to slip.

Steve

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