Post by Charles ManglesPost by Charles ManglesPost by Charles ManglesI have inherited a "Parliament" clock, which was, I think bought by my
grandfather. However I do think it is probably a genuine 200 year old
timepiece.
When I first hung it on the wall, it kept stopping. I then read about the
importance of having the beats equal and set the clock up properly. It then
ran without stopping for weeks until the cord on which the weight was
suspended snapped. I replaced the cord, which is/was catgut, but I have
failed to get the clock to run for more than an hour without stopping.
I
have checked the works and they all look clean and not gunged up.
Anyone have any ideas?
Try with the weight lower, not fully wound up. Take the weight off and
release the ratchet pawl and carefully unwind the gut line. Best not
to
wind
up fully as the pulley might bind under the seatboard especially if it
is
a
new natural gut line. May take some time to become supple.
Check the slot on the pendulum rod that the crutch pin sits within. (Or
crutch forks if clock has this design). The crutch should be free to impulse
the pendulum with "side shake" - a tiny gap left between the crutch and
where it engages the pendulum. Burnish the acting surfaces if they are dull
or rough or gummy with old oil.
Allow the clock to run without the pendulum attatched. It should run down
rapidly with the crutch uninhibited by the pendulum. If it stops, this will
indicate where a problem is.
Ian P.
Hi, Ian,
Thanks for replying and your suggestions. I took the pendulum off and let
the clock run without it for a couple of hours and it ran without stopping.
I then cleaned the crutch and the sides of the pendulum where the crutch
bore on it, refitted the pendulum and set the clock going again. The weight
is about a quarter of the way down. The clock ran for a quarter of an hour,
then stopped. I set it going again and the same thing happened - ran for
about 15 mins, then stopped.
Any further ideas?
Hello Charles,
Well. Now try tilting the clock case, to one side or the other. Disregard
that the clock appears off-level. Concentrate only on getting the clock
running in beat. Adjust by ear, not eye.
If you can arrive at a position the clock will run continuously however
exageratedly askew it appears on the wall, then the level can be adjusted
later by bending the crutch stem. in the direction opposite to the side
lifted / tilted.
Ian
Hello Ian,
Thanks for your further advice, which I followed. Not tusting my ears, I
installed an oscilloscope appon my phone and got the beats exactly equal,
although I noticed that, twice every minute at 15 and 45 seconds, there was
a short and long beat. The clock ran for about an hour before stopping.
Just before it stopped, the crutch hit the pendulum and made it ring, then
the ticking stopped although the pendulum was still swinging, then the same
thing happened again. Quite a lot of vibration was imparted to the top of
the pendulum by this event.
On the upside, the clock is still sufficiently vertical for me not to mind.
The house is old and most surfaces and edges are neither straight nor
vertical or horizontal.
regards
Charles
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Hello Charles,
Not sure if your clock pendulum is one second or one half second beat?
The escape wheel teeth can be examined. If you can remove the anchor pallets
and the back cock (mark where it was positioned as the pallet depth is
crucial)
Place a white card behind the wheel and observe closely under a strong
light. Are the teeth tips straight and equal length? Not curved-over or tip
broken off?
The anchor pallet surfaces touch and slide against each escape tooth
imparting impulse to the pendulum and drop off and caught on the next escape
tooth.
An obvious bent tooth can be straightened upright with short, stubby, blunt
tweazers with polished inner faces (ladies whisker ones unsuitable). Do not
bend, just a gentle but firm stroke from the root to the tip will bring it
upright again.
If the 'arc' of your pendulum bob is weak and the pendulum barely swings
indicates that the movement is worn. All pivot holes gradualy, over time.
become worn in a direction opposite to the acting gear teeth and the going
train therefore cannot impart the force from the weight or spring barrel to
the escape wheel. Hence the clock inevitably stops. The solution is careful
bushing and pivot polishing and if necessary refacing worn pallets.
Ian
Hi, Ian,
Thanks for that. I am away at the moment, but when I get back I will check
over the escape wheel and the drive train for bent or broken teeth.
It's a one second pendulum.
However your point about the position of the back cock may be relevant. I
have already taken the crutch and pallet assembly off, when I replaced the
cord. If, as you suggest, there is play in the fixings and, as far as I can
remember, there was, then I might have replaced the back cock in the wrong
position. How critical is the position?
Charles
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Hello Charles,
Often there are two locating pins driven through both the back cock feet and
the backplate that locate the pallets exactly in the correct position. The
bolt holes that secure the back cock, which were originally round, are often
found filed out into slots so that the cock can be moved down, lowering the
crutch pivot hole and pallets, to compensate for badly worn pallet faces.
Since the clock was running before the gut line snapped and the crutch and
back cock removed, then repositioning may work. To adjust the anchor pallet
depth if the back cock bolt holes are elongated is best achieved by trial
and error. Mark the old position and adjustthe pallet depth very slightly.
The depth must not cause the arc of the crutch to be too wide nor too
shallow. If you closely obverve the crutch it should not "quiver" indicates
too shallow depth. Neither should it have an exagerated wide arc indicating
pallet depth too close. It is likely you will hit on the "right" position.
Don't forget the suspension spring. Examine for kinks and tears.
Ian