Zinnia Run Time Question

Dear Clayton,  I have 2 questions:   

1.  Is it necessary to have a full wind for successful long run time? 2.  Is balancing wheels critical for proper operation ?Thanks for any info.    Don

Aloha Don, 

 Answer to question 1) The length of the run time depends on a number of things, but the main factor in determining run time is the number of  winds of the spring.  The Neg'ator springs I recommend will give a run time of about 40 minutes.  Other constant force springs may be used, however their length is usually much shorter (for example; 22" or 560mm versus 106" or 2690mm) and will give a proportionally shorter run time.  (using these spring examples means a difference between an 8 minute of run time and the 40 minutes).

We have also found that the Zinnia run time can be dramatically increased by eliminating the grease from the bearings.  For our light duty kinetic sculpture purposes the grease inside the bearings actually increases the internal friction and can cause shortened run times.

 By soaking the bearings overnight in mineral spirits and washing out the grease we've been able to double (in some cases) the run time of the Zinnia.  

 I do recommend adding a drop of clock or light oil back into the bearings...but I think this may be mainly superstition as there is probably still sufficient lubrication for our purposes. 

Answer to question 2) The wheels of the Zinnia are first balanced and then unbalanced with the unbalancing weights that are attached behind the wheels.  Recommending that the wheels be balanced first allows me to specify in the Zinnia plans which arms are the best for the placement of the imbalancing weights. 

Balancing is not particularly critical as the unbalancing weights can be placed on different arms to get the sculpture to run.  However, I build my plans primarily for the beginner, and I must make sure that if my instructions are followed the chances of success are going to be good. 

Experienced builders could (possibly) disregard my instructions and still make the sculpture work...so..."critical"...no, but recommended. Enjoy! 

 Aloha.  Clayton

Too Short Run Time Troubleshooting

Dear Clayton,  I can only get about 12 hours on a wind, but the (Genesis) clock is accurate to within about 15 sec during this time. I am temporarily mounted about 3 inches low, not enough for 12 hours difference. Any suggestions? Love the clock by the way.

Thanks

Bob

Aloha Bob, congratulations, and I'm happy you love your Genesis.  It really is a little wonder.  So simple, yet such a great runner, and one of my quietest designs.

Things that cause short run time are generally related to how far the drive weight gets to drop before it hits the floor.

The height that the clock is mounted on the wall is of course the first consideration.  The higher it is mounted, the longer distance the drive weight will have to fall.

The length of drive weight itself is important because an extra long drive weight will hit the floor before a short, squat drive weight.

Also if a larger diameter drive pulley than specified has been installed, that will mean the clock will run on less drive weight, but since the circumference of the pulley is much larger, the cord it reels out with each turn will be much greater and thus give us a shorter run time.

BTW, in my book the Practical Guide, I tell a story about how Thomas Jefferson mounted his clock at the peak of the ceiling in his dining room so that he could get an extra long run time.  He ran the drive weight along to one corner of the wall and marked the days of the week on the wall so that his drive weight could also do double duty as a calendar showing the days of the week.  The only problem is that he didn't calculate his drive pulley barrel radians correctly and had to drill a hole in the floor so that weight shows Saturday in the basement.  The clock is still there in Monticello.  This story always makes me feel better when I do my calculations incorrectly.  Ha.

This story tells us that there is another possibility for a short run time - thick drive cord.  The thinner the drive cord, the more turns your drive pulley barrel can handle.  A thick drive cord will take up much more space as it builds up quickly on the drive pulley.  Thus Jefferson could possibly have solved his short run time problem with some thinner drive cord.  Maybe this will work for you, too.

However, considering that your clock is only running twelve hours, when it should be running thirty hours, tells me that something may be slipping inside the clockworks.  Possibly some wheel or connector or pinion did not get glued tightly, or a glue joint has broken.  A slipping joint would allow the weight to turn the gears, but also as it slips the weight will reach the floor sooner than anticipated.

Enjoy!  Clayton

Simplicity by Steve Stoetzer

Simplicity by Steve Stoetzer

Steve writes:  "Hi Clayton,

Built a Simplicity clock per your plans. Clock runs well, but is several seconds fast/minute. I have tried adding weight to the bottom of the pendulum, but it does not make a significant difference. I was wondering if minimally reducing the diameter of the escape wheel would slow the clock down and wanted your advice in case it would be a move in the wrong direction. Attached are several pics of the clock in case you're interested. It was a very enjoyable project.

Thanks much for your help,
Steve"

Clayton emails:  "Beautiful job, Steve. I especially like your turned weights. Very classy! You did a beautiful job throughout...and that may be part of your problem!

First of all, some mechanisms run fast of slow for the first few weeks. So I always recommend not doing anything for four to six weeks except enjoy the clock's beautiful song and not worry about the accuracy.

After that break in period, if it is still running too fast, you have some choices. The first would be to decrease your drive weight. I actually have the suggested drive weight WAAAYYY too high. The clock should run on about three pounds, but I suggest more because it is a beginners clock and I want everyone - no matter how bad their craftsmanship - to hear their clock run. It's also why I state that the drive weight for each clock will vary.

And this is where your great craftsmanship comes in - maybe because your techniques and accuracy and precision were so good, there's not enough internal friction to be overcome by the excess amount of drive weight - thus making your Simplicity run fast.

If that is not the problem then you'll need to increase the length of your pendulum shaft.

The third treatment you say you have already tried, and that's to add weight to the bob, thus making the apparent center of gravity for the pendulum a bit further away. And also absorbing some of that excess drive weight.

So start with; #1 waiting a while, then #2 reduced the drive weight.

You'll get her purring along just fine and she'll eventually be within a few minutes a day in accuracy.

Congratulations on your fine craftsmanship.

Aloha. Clayton"

A Clock Story to Help Pass the Time (Making a Clock Run Longer; The Jefferson Story)

Waiting for his clock plans to arrive via USPS Mail to Italy (mail to Italy is notoriously and agonizingly slow--can't be helped, sorry), Marco emails:
"Hello Clayton,

Thank you for the list of materials needed to realize the clock. I didn't receive anything yet. Every time I see the postman, I run after him asking if there is something for me, and he always answers "nothing".
Waiting is so exasperating.  Meanwhile I tried to assemble a clockwork, I almost succeeded but I have to wind it up every 8 hours (4.9 foot string and 6 lbs weigh). If you don't mind my asking , I would like to know if there is a method to improve the charge (at least 24h...).

Thank you for being so patient, I'm so happy to talk to such an expert as you are!

Bye, Marco

P.S. Maybe we'll meet one day (even if we live so long way away...) "

Clayton answers,

"Aloha Marco, I completely understand your feeling of anxiousness. I remember the first set of plans I sent away for. The wait was agonizing! Hopefully your postman will greet you with your package very soon. Thank you for your patience.

There are a few ways to make a clock run longer. The most obvious is to hang the clock higher on the wall. That may sound facetious but it is exactly what Thomas Jefferson (U.S. third president) did in his own dining room at his home in Monticello.

Jefferson designed a clock that would run a week on a wind and hung it at the ceiling of his dining room. He then ran the weights down the corners of the room where he had painted on the wall the day of the week. He would wind on Sunday so Sunday was shown in the top corner of the wall. As the weight dropped during the week, it would align with the day of the week painted on the wall.

Unfortunately, Jefferson calculated his radians incorrectly and the clock only ran six days before the weight hit the floor. To solve this problem Jefferson cut a hole in the floor of his dining room and that allowed Saturday to be down in the cellar. (Knowing that the genius of Jefferson occasionally messed up always makes me feel a bit better whenever I screw up a design)

Another way of adding run time is to add another gear at the bottom of the clock's train, but that would require redesigning your clock.

The easiest way in your case is to add a pulley. A single pulley will double the run time - but you must also double the drive weight. Still that would only give you 16 hours run time.

Because your clock only runs for 8 hours and you want to wind it only once a day, your clock would require a combination of pulleys to at least treble the run time. Or you could use a combination, such as hanging the clock higher on the wall and using a doubling pulley.

Rewinding a clock mounted high up on a wall is a bit more difficult - Jefferson brought in a ladder each Sunday to wind his clock. I am presently working on a new clock design with a Huygens Endless Chain rewind system that should simplify rewinding a lot.

For most of my clock designs I recommend stopping the pendulum when rewinding the clock because the force going through the system changes during rewinding and that can affect how the pallets and escape wheel interact. With a Huygens Endless Chain system there should be no need to stop the pendulum when rewinding because the force through the system should remain fairly constant. The big plus is that rewinding time should be decreased dramatically for each clock with the Huygens system.

Please send me pictures of your clock experiment.

Enjoy! 

Aloha. Clayton"

Letter from Clockster: Clock Design, Run Times and Recommended Reading

Here's an interesting letter thread that covers a few topics you might find interesting.  Builder Neil writes:

"Howdy Clayton,

I'm currently at uni finishing up my masters in Architecture, and in the past I've worked on a few different clocks just as a hobby.

I got most from garage sales that didn't work, and really enjoyed getting them running again...although not all work accurately. but you get that when your learning.

I'm really interested in trying to match my ideas about architecture and my hobby for clocks into one and design a few grandfather clocks for particular buildings and architects.

My big question for you would be, what books did you pick up to learn the art of what you do, or where you trained in clock repairs and then added your love of wood work. If you can think of any good books that might show how the design of clocks is done, do you mind forwarding me the names and authors so that I could have a look through.

Thanks heaps for the time and love the work you do.

Regards,

Neil Brown
Ba. Design (Architecture), UON
Undertaking Ma. Architecture, UON"

My response:

"Aloha Neil, sounds like you've gotten the 'bug' too. It's a wonderful malady.

You can check out my recommended reading section for books. The very best for clock mechanics is Modern Clock. The others there are great, too.

About design, I had two instructors - friends of mine that made a difference in my design. Marc Tovar, (check out his site in my links) said "simply bend a line until it is pleasant," and the other friend, a fabric artist told me once when I was stuck "you are trying to design 'beautiful.'  Design 'ugly.'"  She was giving me freedom from my own constraints.

Good luck in your career and in designing these most wonderful mechanisms.

Aloha. Clayton"

The thread continues from Neil:

"Aloha Clayton,

I've ordered the books you recommended, and I've been instructed that I'm getting them for my birthday so I can't start anything until then.

One question I havent been able to find either on your site, on in any of the others that I've been looking at, is how often do these clocks need to be wound up? Is it everyday, every week, a month. I'm interested in making one for my In-laws, but dont think they would appreciate it as much if they needed to wind it up every morning. It would most likely stop and only be started when they knew I was coming over.

Alternative: what are the designs that yourve made that last longer between winds, or can this be altered easy enough from a beginers point of view.

Thanks again for the advice on the books. Cant wait to get these bad boys started.

Neil Brown"

Last word fom me:

"Aloha Neil, I think you are gonna enjoy those books, especially Modern Clock. It will explain everything about clocks and how they work. Although it is mainly about metal clocks, much of what he writes about will apply just as well to wooden mechanisms.

The length of time between winds, and how long a clock will run on a wind depends upon a lot of things.

The easiest way to make a clock run longer, since it is weight driven, is to hang it higher on the wall. This may sound facetious, but it is exactly what Thomas Jefferson did in his home in Monticello. In his dining room Jefferson designed a clock that mounted at the ceiling, and I believe he wound it each Sunday. As the weights dropped, they would align with the days that were marked on the wall of his dining room. Unfortunately, Jefferson calculated his wind barrel radians incorrectly and a hole in the floor had to be drilled for the weight to drop through and into the cellar to get a full weeks run time. Saturday was in the cellar.

A pulley on the weight cord will double the run time of a clock. A set of pulleys will treble or quadruple the run time, and extra gearing will also make the clock run longer.

Most of the clocks you see on my main page run for a full day on a wind. To get two days run time is not difficult, but getting a clock to run a full week on a wind takes some doing and is generally not for the beginning clockster.

I believe that the only clocks in that 'week run time' genre that I offer are the Medieval Astronomical Calendar Clock and Attempt.

Of course there's always Electra and Toucan that NEVER need winding.

Aloha, Clayton"

Toucan, an electromagnetic clock, built by Jeff Hecht