Westminster strike not stopping

clockboy · April 23, 2018

I have serviced/repaired a few Westminster clocks without too much trouble. But this one has issue which I can not figure out how to fix. The striking wheel does not stop turning. I can not see what should stop it once it has gone through the sequence. I guess that it is a sequence issue as all stop pins on the warning wheels are OK. I have posted a couple of vids maybe you can spot what is wrong.

IMG_2394.mov

Top view.mov

oldhippy · April 23, 2018

The wheel on the outside that determines how many times it chimes remove that. Each time you turn the minute hand the chime wheels should rotate once and get trapped by the lever catching the pin, the other wheel with a pin next to the fly should be about 12. Replace the wheel making sure the hour part is the same as the hour on the centre wheel, it has four fingers the shortest is quarter past the longest is the hour.

With some chimes, the wheel you have taken off has a shape behind it like a v and a lever drops down in that. That will right the chime by its self. I cannot find your movement but this photo has the wheel you need to remove.

clockboy · April 24, 2018

Thanks I will have another look this morning. In the plate behind the chime timing wheel are two wheels with pins. The nearest one I think stops chimes when a silence mode is selected (I have removed the lever just to see whats happening) and there is a second wheel (next one in) that has a pin on it but it seems to missing a curved lever above it which I presume is what stops the chime wheel turning after one of it's quarters.

oldhippy · April 24, 2018

I have had another look at the videos. The video showing the chime timing wheel is not right as I have noticed when it should be at stop some of the hammers are lifting. Also when the chimes go into the warning the stop lever that drops into the timing chime wheel should be rising out of the timing chime wheel, on the video yours is still dropping. This its self will cause the chime to trip. Its because all the chiming levers and wheels are not lined up correctly.

clockboy · April 24, 2018

Thanks I think you may have cracked it. The wheel that spins and arrests the chiming wheel was 180 degrees out so I removed plate and moved the wheel reassembled as your instructions and all seem well !!!. Thanks.

I will put it on my test rig and see how it runs. I have ordered a new mainspring for the chiming side as the old one was split and badly set. I fitted a under strength one out of my stash for the tests but to get the correct strength I have had to order a longer one & I will have to shorten it. What fun!!!

oldhippy · April 24, 2018

Let me know how things progress.

clockboy · April 24, 2018

Ok here's the follow up of re-sizing a mainspring. I could not get the correct length vs. the strength so I purchased a longer spring.To double check i was cutting the new spring to the correct size I measured the old one with a piece of string. I then marked the new spring and cut with a diamond wheel. However when I tried to drill the end hole the drill just would not cut so I softened the metal with heat. After drilling the holes I finished with some filling. However I got a unwanted bend just before where it hooks and I suppose because the metal was now soft I could not remedy this so I had to cut off another inch and do the same process again and this time it worked treat. In future if possible I will see if I can purchase a diamond drill to make the hole. See some pics of the procedure.