Morbier w/Crown Wheel & Verge runs slow

[Tom Englund]

Greetings, all, and welcome to another edition of "Tom's Stumped".

Today' episode features a Morbier/Comtoise with a verge and crown wheel escapement and folding pendulum. The customer complained that the clock's strike was erratic and that it runs 10-15 minutes a day s l o w . She swears that it has kept good time in the past with the current pendulum.

The clocks 2 weights are 9 lb, 11 oz, and 8 lb 8 oz. Right now, I have the 9:11 weight on the time side to try to speed it up.

After cleaning, repivoting and bushing T2Back and correcting the strike problem, I was hoping it would keep time. The pendulum bob is at its highest adjustment. Still runs very s l o w . Probably 10 minutes a day.

I'm not afraid to shorten the pendulum, but given that the owner swears this length has worked in the past and given my lack of crown wheel and verge escapements, I figure it's a good idea to pick the brains of the experts. That would be y'all.

I have read that CW&V escapements are susceptible to rate changes corresponding to factors other than pendulum length. But the source didn't go on to elaborate on how to utilize that characteristic.

Have I left anything out? It's late at this point, so I'll be looking for sage advice in the morning.

Thanks for reading and for your help.

Tom

 

[Tom Englund]

Greetings, all, and welcome to another edition of "Tom's Stumped".

Today' episode features a Morbier/Comtoise with a verge and crown wheel escapement and folding pendulum. The customer complained that the clock's strike was erratic and that it runs 10-15 minutes a day s l o w . She swears that it has kept good time in the past with the current pendulum.

The clocks 2 weights are 9 lb, 11 oz, and 8 lb 8 oz. Right now, I have the 9:11 weight on the time side to try to speed it up.

After cleaning, repivoting and bushing T2Back and correcting the strike problem, I was hoping it would keep time. The pendulum bob is at its highest adjustment. Still runs very s l o w . Probably 10 minutes a day.

I'm not afraid to shorten the pendulum, but given that the owner swears this length has worked in the past and given my lack of crown wheel and verge escapements, I figure it's a good idea to pick the brains of the experts. That would be y'all.

I have read that CW&V escapements are susceptible to rate changes corresponding to factors other than pendulum length. But the source didn't go on to elaborate on how to utilize that characteristic.

Have I left anything out? It's late at this point, so I'll be looking for sage advice in the morning.

Thanks for reading and for your help.

Tom

 

[Tom Englund]

Originally posted by Tom Englund:
Greetings, all, and welcome to another edition of "Tom's Stumped".

Today' episode features a Morbier/Comtoise with a verge and crown wheel escapement and folding pendulum. The customer complained that the clock's strike was erratic and that it runs 10-15 minutes a day s l o w . She swears that it has kept good time in the past with the current pendulum.

The clocks 2 weights are 9 lb, 11 oz, and 8 lb 8 oz. Right now, I have the 9:11 weight on the time side to try to speed it up.

After cleaning, repivoting and bushing T2Back and correcting the strike problem, I was hoping it would keep time. The pendulum bob is at its highest adjustment. Still runs very s l o w . Probably 10 minutes a day.

I'm not afraid to shorten the pendulum, but given that the owner swears this length has worked in the past and given my lack of crown wheel and verge escapements, I figure it's a good idea to pick the brains of the experts. That would be y'all.

I have read that CW&V escapements are susceptible to rate changes corresponding to factors other than pendulum length. But the source didn't go on to elaborate on how to utilize that characteristic.

Have I left anything out? It's late at this point, so I'll be looking for sage advice in the morning.

Thanks for reading and for your help.

Tom

 

[K Reindel]

Greetings Tom, hope you're doing well these days.

Have you tried reversing the weights and running the time side with the lighter weight? Reducing the pendulum swing with this style of escapement just might give you a little more of what you're looking for. It's worth a try, and eliminates the less intuitive but obvious question.

Kind regards,
Ken

 

[David Robertson]

Tom,

You may have already done this... but...

I would start with counting the train and seeing what the pendulum BPH needs to be for the clock. Then measure what it actually is to see if the pendulum is too long or if there is another problem.

David

 

[Jeremy Woodoff]

The pendulum is suspended by a silk thread. Is it possible this had been unintentionally lengthened?

 

[Joe Jones]

Slow? Perhaps the canon pinion is slipping.

 

[Scottie-TX]

First, I believe also I've read that contrate wheel escapements are more prone to regulation variations with respect to power. As "KR" suggests - put the 8.8 on time side. It is counteruntuitive to conclude that more power makes clock go faster. Actually more power may slow it. That is so because the angular amplitude of the pendulum is reduced with less power so ergo - shorter time cycle per bob cycle.
I hesitate to recommend it but increasing distance between verge and EW could also result in smaller impulse, weaker pendulum motion, and faster regulation.
However, ten minutes a day: I had one of these for years and ten minutes could be nearly an inch decrease in pendulum. TEN minutes is a large number.
Keep us posted .

 

[Mike Phelan]

Verge escapements are prone to an increasing rate if there is not enough arc due to loss of power.

I do not see any reason to suspect that a customer would have swapped the pendulum!

What was the striking problem?

 

[Tom Englund]

Good Morning All-
Wow! I was hoping for a reply when I logged on this morning. This is impressive. Thanks for your replies.

Ok. Ken, I have just reversed the weights, putting the 8-1/2 lb on the time side. Thanks for that offer. We'll see if it does the trick.

David, I've not counted the train. Being so dyslexic(sp?), that's one of my least favorite things to do in the world. "29, 30, 31, 32, 33, 36, wait. Where was I?" I wind up having to mark wheels up with markers in increments of 5 teeth so I can recheck. Don't like to do t h a t after I've already cleaned everything. I will resort to it, though, if I must.

Jeremy, I had not considered suspension. Actually, the pendulum leader is now suspended by monofilament fishing line. It had been changed to that before it came in, and I put new monofilament back on it after cleaning. I've got the leader pulled pretty much up to the top, but completely free to swing. Could the monofilament be too stiff? What would I replace it with and where would I get it?

Joe, the hand clutch on this clock is on T2. The arbor protrudes through the cage post and carries a double wheel that turns both the minute and hour wheels. The hand clutch is behind that double wheel, outside the cage, in front of the cage post. I don't think it's slipping, but will mark it, watch, and get back to you.

Scottie, You've touched on a tricky idea. The clock was stopping... the verge was catching up on the CW tips. I spent a bunch of time trying to adjust that. No adjustment built in on the bottom pivot, to I had to tweak the post that holds the bottom pivot. For a time, the CW was higher than it is now. The arc was reduced as you indicate. Also, the clock would not run - I think the duration of actual impulse was not enough to keep the pendulum swinging - or perhaps the amplitude was reduced to a point that the verge couldn't let the nest CW tooth pass.

Maybe there's a sweet spot in that adjustment I haven't found. I spent a morning getting it back to the point where the clock will run at all. If ya'll think that's the answer, I'll pull up my boots and wade back in.


Mike, the strike problem involved the rack tail - the vertical piece of wire that touches down on the snail when the rack drops. It needed a massage so that it landed on the appropriate flat consistantly.

I'll keep checking in for your input and will let you know how things are progressing.

Thanks-

Tom

 

[Jeremy Woodoff]

Tom,

I don't know whether the material of the suspension would make any difference. Silk thread is available at sewing supply stores, or probably anyplace that sells sewing thread. I imagine the fishing line will last a lot longer.

Jeremy

 

[Tom Kloss]

Tom

I don't think the suspension material is of any significance. I have a CW comtoise that has a piece of cotton string for the pendulum hanger, it keeps perfect time. Since these clocks, are usually old, I would check the height of each of the teeth on the crown wheel. Make sure their the same height. The tooth height of mine varied between as much as +/- .015 of and inch. The escape action was erratic until I dress the teeth to the same height. Also, the pivots of the link between the verge rod and the pendulum hanger. You don't want any slop at this point. I don't understand the CW not having an adjustment screw as that's the only way adjust the depth of one of these. That is, unless the verge has some sort of an adjustment on it. If that's this case I've nerve seen one like that.

Tom

"Sometimes you really don't know if your being rewarded or punished" :biggrin:

 

[Tom Englund]

Ok, gents, here's the update...

I've reversed the weights (8.5 lbs on the time side), marked the hand clutch to check for slipping, and corrected some slop (that's Ted Brachfeld's word) in the link between the crutch and leader. There seems to ge no slipping in the hand clutch. In about 6 hours, it has lost about 3-1/2 to 4 minutes. Tom, I just saw your message for the first time, so I have not dressed the CW teeth yet. Perhaps that's the next step.

More to follow...

Tom

"Sometimes, you don't want to know whether it punishment or reward. Sometimes, they're the same thing."

 

[Joe Jones]

I've got the leader pulled pretty much up to the top, but completely free to swing.

Hi Tom,
This may be the clue we need. Try lengthening the suspension string. I am guessing that there is an oval "hole" in the leader through which the hand shaft passes. I would suggest adjusting the suspension so that the leader is as low as the hole will allow without interference from the shaft. If it's too slow for the adjustment in the pendulum, you can always pull the leader up a bit,again using the suspension, and then adjust the pendulum with the rating nut in the customary fashion.
Good luck,
Joe

 

[Mike Phelan]

Joe
Isn't Tom trying to shorten the pendulum?

Tom
The suspension material does not have any effect on rate; I, too, would check the escape wheel teeth.
What sort of arc does it have - plenty of recoil? Are the pallets well polished? Equal drops?

 

[Scottie-TX]

The suspension material does not have any effect on rate;

Hmmmm. "The suspension material does not have any effect on rate;"
Have you ever tried a TUNGSTEN suspension? Glass?

 

[Tom Englund]

'Morning clocksters...

Yup, I do need to speed it up... Joe, thanks for your suggestion.

Yes, that will be my effort on this clock today - checking the CW teeth for consistant height. I gotta say up front - the escapement seems consistant - but I will check. Pallets are well polished. Drops about equal. Seems like we may be closing in on the obvious choice: shorten the pendulum. Ted did say more than once, "Customers will lie to you."

I'll let you know about the 'scape teeth.

Tom

 

[David Robertson]

Tom...

I know you do not want to count the teeth, but I think you are to that point. It will give you some hard data from which to work... It will eliminate the "he said... she said" from the analysis...

David

 

[Joe Jones]

Oops, I read it wrong.

To quote Emily Litella, "Never mind."

 

[Tom Englund]

Joe, I often quote Emily. More often as I grow more and more hard of hearing.

David, of course I should count the teeth. I'm sure there are many who count every time train as part of the protocol. I know a couple of them...

In a last ditch (unless I find yet another ditch) effort to avoid that, I cut a small piece of brass tubing to slide over the pendulum rod, beneath the bob and above the regulator nut. Randomly, I chose (sp? that word always confuses me) 1-1/2". Effectively, the pendulum is now shorter. Now, with the adjusting nut at about mid point, the clock seems to be doing well. I did this about noon, so we'll see how far off it is tomorrow.

I think I may like this "fix" in that it won't permanently shorten the rod. This is already the second clock to use this pendulum, (apparantly), and who knows... another clock may need this pendulum some day. The clock has a case and the pendulum doesn't show. I can make the tubing look pretty good by dressing it up a bit.

What do you all think? Workable? Acceptable?

Good evening to all of you kind clocksters who are following this tribulation. And, again, thank you.

Tom

 

[harold bain]

Tom, I like your ingenuity. Pendulum not original, and doesn't show. Alterations easily reversed. Perfect :biggrin:
Harold

 

[Scottie-TX]

And I'll bet your sleeve is close to an inch!
Yes. Great fix. I've done it many times. It doesn't look klutzy and again; easily undone by anyone.

 

[Tom Englund]

Thanks, Harold & Scottie. I appreciate your reinforcement. Harold, I've been wondering when you would chime in on this one. Good to hear from you.

Tom

 

[K Reindel]

Sounds good to me. Leaves options open and, should work. Great thinking.

Ken

 

[Mike Phelan]

Originally posted by Scottie-TX:

The suspension material does not have any effect on rate;

Hmmmm. "The suspension material does not have any effect on rate;"
Have you ever tried a TUNGSTEN suspension? Glass?

Not on this context of a silk one, Scottie!
OTOH, springs certainly do, as witness to many posts here saying that their clocks gain.
No tungsten or glass suspensions in my scrapbox, but some fishing line I use for radio drive cords.

 

[Mike Phelan]

Go for it, Tom.

 

[Tom Englund]

OK Clockmeisters, I'm going to see if I can post a picture of the fix I've constructed.

 

[Tom Englund]

Well, clearly, that didn't work. If you're interested, let me know how. I clicked on the image window above and inserted the title of the picture in my picture file.

Those who are challenged by current technology best stick with ancient technology within the confined of their day jobs. That would be me.

Tom

 

[harold bain]

Tom, I have the same problem with posting photos, my computer skills not being up there with my clock skills.
I have a modern German wag on the wall type clock that I had to make the same alteration to the pendulum. No one has ever made any comments on it, although the pendulum is totally visible. Keeps time within a minute or less a week now.
Harold

 

[shutterbug]

Regarding counting the wheel teeth, you can get a pretty accurate beat rate if you have a beat counter. Start it counting at about 10 minutes before the hour at a known position. Let it run for 4 or 5 hours, and stop the count at the same place - as exact as possible. Devide the total count by the number of hours you let it run and you have the beats per hour rate. You can take the pendulum off to speed up the passage of time without affecting the count.

 

[Tom Kloss]

Scottie:

Actually my suspension material of preference is titanium. 0 BPH, never get out of beat and correct twice a day.

klossee

 

[harold bain]

Tom, that is correct more often than a politician would be!!! :biggrin:
Harold

 

[Mike Phelan]

Originally posted by Tom Englund:
Well, clearly, that didn't work. If you're interested, let me know how. I clicked on the image window above and inserted the title of the picture in my picture file.

Those who are challenged by current technology best stick with ancient technology within the confined of their day jobs. That would be me.

Tom

Tom
Your picture needs to be somewhere on the internet so we can all see it, not on your computer, that is not visible to the rest of the world.
It needs to be parked on (uploaded to) something like flickr.com - look at the top post in the "Clocks" section.
Have a go - let us know the outcome, as it is an important tool to be able to use here.

 

[Tom Englund]

Thanks, Mike, for directing me to the tutorial.

This morning, the clock is within 30 seconds of correct from yesterday at 11:00. So we'll get there now. Plenty of room for adjustment in either direction.

Here's the height adaptor...




Thanks, all, for your suggestions and help with this one...

Tom

 

[Ken M.]

Tom,
Assuming that it was the same pendulum that once kept good time, look at the rod in the area where the crutch contacts it. There should be indications of wear from years of use. If the wear is in a different place (like below the contact spot) then we know that it has been moved. If the wear is at the contact spot, we probably need to look elseware for the solution.

Ken

 

[Mike Phelan]

Looks like a good job, Tom :biggrin:

 

[Tom Englund]

Hi Ken,

Thanks for your suggestion. On this clock, the crutch never touches the pendulum rod. The crutch connects to the leader via a linkage piece, and the pendulum rod hangs from the bottom of the leader.

Unless, I'm misunderstanding you, the wear point you suggest looking for would not be present in this case.

Tom

 

[Tom Englund]

Thanks, Mike.

 

[David Robertson]

Tom...

Seems the inevitable conclusion you have reached is that the present pendulum and bob never did keep proper time. A lighter bob or a shorter pendulum assembly or a heavier rod would have been required to achieve the faster running that was necessary. You have chosen a shorter pendulum assembly and fixed the problem.

Just goes to show how reliable the information we get from our customers is sometimes. I have never understood why someone will tell you something that just isn't (and cannot be) true. Sometimes I think they don't know... other times I get the feeling that if they tell you everything is ok, they think you may not charge them as much for fixing the problem... try to make you feel it is somehow your fault or something you just don't know how to fix...

David

 

[Tom Englund]

I'm right there with you, David. Thanks for your help on this one.