Sometimes Reality Doesn't Cooperate: The Monotonous Pi Clock

Not all clock plans make it for sale on my website.  This is the story of Pi.

Above:  Monotonous Pi 3D Renderings made from my dxfs
by my friend, Oleg in Russia

Below:  Pi, actually built by me, in motion below:

The Monotonous Pi is a kinetic sculpture posing as a clock. It has all the parts of both a clock and a kinetic sculpture. That huge circular pendulum has a very slow forward and back oscillation of approximately 38 beats a minute. Monotonous Pi has its roots in the Medieval 1300’s when the verge and foliot clocks were the techie’s state of the art timepieces. They weren’t very accurate. They could be off twenty minutes a day…plus or minus. That’s a pretty huge possible error spread, and that error rate in timekeeping, with only slight improvements, continued until the late 1600’s when the seconds pendulum was introduced by Galileo and others - like Christiaan Huygens (who, in my opinion, never gets enough credit). But not all verge and folio clocks had such problems with accuracy. Christiaan Huygens (1629-1695) had a suggestion that I’ve incorporated into all of my verge and folio clock designs (except Monotonous Pi), and they are actually quite accurate timekeepers. Huygens recommended a return spring on the verge to increase the clock’s accuracy. My designs, other than Pi, have just such a return spring which is created by the spread of the cord from which the verge and foliot is suspended. Most verge and foliots in those early days were suspended by a single strand of silk. By changing over to a loop of cord we can add that return spring advantage to our verge and foliot clocks that Huygens suggested, and this simple improvement increases their accuracy dramatically. You can see that loop of cord suspending the verge and foliot in my Medieval Rack, Holologium, and Wee Willie designs. But…Monotonous Pi is not one with a looped suspension cord or return spring, so its accuracy is very similar to the workings of those early Medieval clocks - which is not very good…but sometimes it’s right! However, on the other hand, as a kinetic sculpture the Monotonous Pi is excellent! Pi is a visual delight. It is lovely to watch Pi’s slow oscillating movement forward and back. And it does try so hard to keep good time, even though it’s not very good at it. Still…Monotonous Pi is one of my favorite sculptures. Pi is truly a delight to watch.

Aloha, Clayton


NEW! The Mantis Clock


Mantis by Clayton Boyer

Mantis has a large, slow, two second beat compound balance pendulum.  The pendulum on Mantis is about 46" (117cm) making it actually longer than a regular straight, hanging seconds pendulum, which are usually around 42" (107cm).   However to get a straight, hanging pendulum to tick at a two second beat, that pendulum would have to be over thirteen feet long.  Because Mantis uses a compound balance pendulum, we were able to create not only a dramatically shorter pendulum, but one with an artistic flare that beautifully accents this clock.

Mantis has a special escapement that allows for a very large and dramatic pendulum arc.  With its pendulum swinging with about forty degrees of arc, it makes Mantis as much a kinetic sculpture as it is a clock. The way the Mantis escapement is designed helps modulate its tone and creates a slow, gentle "tick" with each contact with an escape wheel tooth.  The slow swing and gentle sound of the pendulum is relaxing and mesmerizing, and the movement is a delight to view.

Mantis by Clayton Boyer

Hiding behind the mobile crescent at the right side of the dial ring is a motorized remontoir making daily rewinding of this beautiful sculpture unnecessary. The clock is powered by a weighted motor arm that automatically rewinds the clock.  The amount of drive weight is adjustable by simply changing the amount hanging from the cord on the right of the clock.  The difficult part for me was determining what to hang there.  There are so many beautiful options.  I tried various rocks (which looked pretty nice), glass spheres, a painted fishing weight, and finally settled on the clean look of copper tube.  That tube weighs 3.6oz (102gm), and to avoid over stressing the motor, the amount of added weight drive should be 8oz (227gm) or less.  The rewinding of the remontoir motor arm is powered by an onboard nine volt battery which will keep the clock running for about three to four months.

Mantis has movement throughout its design - from the massive swing of the pendulum, to the remontoir motor arm actuating the bobblehead and crescent that accent Mantis' "broken" dial ring.  The Organic clock design also has a "broken" dial, however that design is mainly aesthetic.  The dial ring of the Mantis is "broken" for a different reason - which is to allow the viewer a better view of the internal workings of this sculpture. 

Mantis was named because of the similarities between the antennae of a praying mantis and the upper part of the Mantis' double split pendulum.  As it happened, the day before the Mantis was completed we were  surprised to see that the Mantis clock had been visited by its namesake, a praying mantis. Shown going for a ride on the bobblehead in the picture below.  The praying mantis spent the night hanging out on the bobblehead, however I still needed to add the decorative brass screws, so I moved him/her to the nearest rosebush.  Obviously, such serendipity must equate, in some way, to a celebrity endorsement!

A Mantis on Mantis
Enjoy, Clayton Boyer


Beautiful Video on Making a Wooden Clock by Rasim Ramadan


"A Clock from the Fairy Tales"

Excellent and beautifully made video by builder Rasim Ramadan showing his Organic Clock build. 

Enjoy!  Clayton


Troubleshooting the Dial Train when the clock runs well but the hands are not turning correctly

Modern Times Clock
(just some eye candy unrelated to this post)

Berry writes:  I have everything completed now on the clock but having issues (I bet you hate letters like this). The motor drives the Center Wheel just fine. The Third Wheel and Escape Wheel and Pallet chug along day and night. It looks great. Unfortunately the Minute and Hour hands don't keep the time. I marked the Center Arbor Tube and Hour Arbor Tube with a spot of ink at the top. After one hour they were at the 9 o'clock position. Fifteen minutes later they're both back at 12.

I've no idea if you can help, but I'm hoping you can.

Best wishes - stay healthy, Berry

Aloha Berry, if I understand correctly, it sounds like something is slipping or some glue joint may have come apart.

Here are some of the places that slippage may occur in the dial train of these wonderful mechanisms....

Check to make sure that the center wheel tube is pressed tightly inside the center wheel.  That tube should travel with the center wheel and make one revolution every 60 minutes.  

To that tube is added the cannon pinion and its tube.  The cannon is held to the center wheel tube by the leather plug system that allows for synchronous movement of the minute and hour hands.  The minute hand is attached to the other end of the tube that is tight inside the cannon.  Make sure that the tube is tight inside the cannon and minute hand and they are not slipping.

The clock will run like that and show the minutes, but we need to also see what hour it is, so take off the minute hand from the cannon tube and slide the intermediate wheel onto its rod.  The cannon can now drive the intermediate wheel.  The intermediate wheel has glued to it a pinion.  Make sure that glue joint between the intermediate wheel and it pinion is tight.  

The intermediate pinion drives the hour wheel.  The hour wheel has a tube pressed tightly into its center.  Make sure that tube in the hour wheel is not slipping.  On the other end of that hour tube the hour hand is pressed on tightly.  Check to be sure that hand it tight to the hour tube as well.  Once you have slid the hour wheel/tube/hand assembly onto the cannon/tube assembly then you can press on the minute hand.  The minute hand should be tight to the tube.

Somewhere in that system from center wheel to minute hand, something is slipping...OR...

OR, it may not be slipping at all, possibly just the opposite.  

There is a possibility that the three tubes are binding somewhere and not running freely with each other.  The center wheel tube, and the cannon's minute tube and the hour tube must all be able to turn smoothly and easily on each other, and the center wheel tube needs to turn freely on the center wheel arbor.

If, for example, you forgot to put the leather plug in the cannon pinion and screwed the set screw directly into the center wheel tube then that tube will be dented and it will not move freely on the center wheel arbor.  That dent will cause the tube to stick to the rod and not move freely.

Sometimes tubes get dented or bent in other ways and will not turn freely on the rod or tube they mate with.  Test all tubes for free motion.

Sometimes after the rod or tube has been newly cut there are residual barbs and metal fragments on their ends that need to be cleaned up and removed.  Polishing the arbors and cleaning up the cut ends of the rods and tubes helps this tremendously.

All of the rods and various tubes must run easily on their mating rod or tube.  

Hopefully this gets your clock running nicely.  If not, send me a video showing what's happening and I can probably make a better diagnosis.

Enjoy! and send pix when you get your project completed.

Aloha.  Clayton

Depthing and Troubleshooting

Residual internal friction is the bane of our wooden clock movements.  Friction can happen in a variety of places, and that’s why I always recommend Depthing as we build to help find and eliminate as much internal friction as possible before the assembly is completed. 

The Depthing process takes time, but it also saves time at the end in trying to find hidden friction points.  Once the Depthing of all the pieces is complete, it almost assures that the clock should run well once the pendulum is put into motion. 

Depthing is a simple process of testing one wheel with its pinion using the clock frame these two gears will be running in.  Depthing is testing ONE wheel and ONE pinion...not the whole train of gears at one time.

 In reality while building our clock, we don’t want to just test one wheel and one pinion.  We want to test those two gears on their completed assemblies, just as they will be running in our clock. 

 We want to first create a completed wheel arbor assembly (i.e.: wheel, connector and pinion on its arbor).  Then create a second complete wheel arbor assembly.  Then test these two completed arbor assemblies, with their spacers, in the reassembled clock frame. 

 I always recommend Depthing as the clock is being built, however, if the clock has already been assembled, to depth correctly the clock is taken completely apart.  All the arbors removed from the Frame, and then one wheel assembly and its matching pinion assembly are put back into the clock.  The clock frame is totally reassembled with just those two arbors, and then the wheel set (one pinion and one wheel is a wheel set) are tested by gently blowing on the large wheel.  This process will detect even the slightest bit of internal friction that could stop the clock. 

 Internal friction may be caused by the contact surfaces of the wheel and pinion, or possibly the teeth may be bottoming out in the dedendum (the valley between the teeth), or even a tight set of spacer tubes could be binding the arbor in the frame.  Any and all of these can be detected by proper Depthing.

 Because clocks never run backwards, only one side of the teeth is ever used.  That is called the Contact Side of the tooth. 

 If a space is too narrow between teeth we want to take the wood off of Non-Contact surface of the teeth.  Avoid sanding wood off of the contact surface of the tooth. 

Removing wood from the back of the toot allows the spacing of the front of the teeth to remain constant while at the same time opening up the space between the teeth enough for proper clearance. 

A clock wheel travels only in one direction, and with only one wheel and one pinion in the clock’s frame it gives us the opportunity to first visualize the direction that the wheel will be turning in the clock, and to decide which side of the teeth is the contact side. 

With one wheel and one pinion being tested inside the reassembled frame we are also simultaneously testing other parts, like the Frame’s arbor holes and the arbor’s spacers, and this allows us to make sure that these parts are not causing the increased internal friction. 

If the spacers are causing internal friction they can be filed or sanded slightly to allow freedom of motion of the two arbors.  There should be about 1/16” (1.5mm) of end play (front to back movement) in each arbor.

 Depthing also can let us know of another potential cause of internal friction - the arbor holes.  Possibly the arbor holes are binding because the holes in the front and back frame are not aligned, or because the drill holes are too small or because the fibers inside the drill hole are going in the wrong direction for that particular arbor.  

 Because our drill presses only turn the drill in one direction as we drill each of the arbor holes in the frame, that means that every other drill hole has wood fibers inside the hole that are facing in the opposite direction that the arbor will be constantly turning as the clock runs.  This is usually not a big problem, but if those opposing directional fibers should get damp and swell they can easily stop an arbor.  Burnishing the inside of the arbor hole can help in a couple of ways.  It can flatten the wood fibers and also add paraffin to decrease friction.  To burnish, simply chuck an arbor rod in a hand drill, add paraffin to the rod, and run it in and out of the hole.  Reverse the direction of the drill and burnish again.

 Then, after that first wheel set has been tested and the internal friction removed, the clock is then disassembled again and the first wheel arbor is removed.  The next arbor in the train is then to be tested the same way - one wheel and one pinion - with their spacers inside the reassembled frame - with a gentle puff of air on the large wheel.

 All of the wheel sets (one pinion and one wheel) throughout the entire clock are separately tested using this Depthing procedure.  Once the Depthing is complete you can be sure that the wheels, pinions and spacers are all going to work properly. 

 Once all the wheels and pinions are depthed correctly and the clock still occasionally stops, that may mean that the problem probably is NOT in the wheels or pinions but somewhere else, such as two parts rubbing causing increased internal friction.  This can happen as an arbor moves forward or back and begins to press its spacer into the clock's frame with enough force to stop the clock.  

 You can visually check.  When a clock has been running well and then spontaneously stops for no apparent reason, check to see if the arbor has moved forward or back and is rubbing on the frame or some other part.  In a clock that is not properly depthed, this movement of the arbor, combined with the improper Depthing might create enough internal friction to cause the clock to stop....not from just one problem, but from the combination of two or more residual problems.

 The most common place for the arbor shifting to happen is at the Center Wheel arbor and its Cap (but any arbor can shift increasing internal friction).  On the Center Wheel arbor it is usually not the arbor itself shifting that is causing the friction, but the minute and hour tubes that have slid forward into the Cap.  

 A common cause of shifting arbors is mounting the clock to a wall that is not plumb.  If your arbors are shifting, check the plumb of the wall.  An easy fix for this is to shim the clock’s frame so that the clock sits level on the wall. 

 Also, once the clock is mounted level, another fix that can help minimize shifting arbor friction is to cut a couple of nylon or Teflon washers to fit between the tubes and the Cap.  These washers will allow the tubes to turn at the Cap, but not rub on the Cap.

 To cut your own washers, you can use something like a plastic coffee can lid.  Drill the plastic with a brad point bit that is just slightly over-sized for the arbor.  I use brad point bits for these center holes because they give a cleaner cut and don't leave a ragged plastic edge around the hole.  Once the center hole is drilled, the washer can be cut to size from the lid with scissors or even a larger brad point bit.

 Sometimes internal friction as slight as the tubes rubbing on caps is enough to stop a clock, especially if it happens in concert with another source of internal friction.

 To minimize internal friction even more paraffin can be used on the contact surfaces of the teeth, on the arbor rods, and in the arbor holes in the frame.  I prefer using a color coordinated Crayon because the paraffin of a Crayon is softer than candle wax and the sharp tip allows us to get the paraffin in between the teeth easily.  But not too much!  Too much paraffin can pack into the dedendums (the valleys between the teeth) and cause the teeth to bottom out into the wad of wax.  This bottoming out will stop the clock.

 Another source of internal friction that has nothing at all to do with the clock’s gear train could be the groove in the pendulum pivot rod.  Too deep a groove can cause the clock to stop.  The groove in the pendulum pivot rod should be 1/32” (0.75mm) or less in depth.  We want only enough depth to hold the sharp, knife-edge point of the pendulum pivot from slipping side to side.

 The Pendulum/Pallet/Crutch assembly can be tested for friction by simply removing the Escape Wheel.  With the Escape Wheel removed, move the Pendulum’s Bob to the side about two or three inches and let it go.  The Pendulum/Pallet/Crutch assembly should continue to rock freely for at least 60 seconds, and 90 seconds is even better.

 If the Pendulum/Pallet/Crutch assembly does not rock freely for at least 60 seconds, check all contact points for friction.  Maybe the arbor holes in the frame are not aligned, or the arbor holes are drilled too small.  Or possibly the Crutch Pin slot in the Pendulum is too tight.  The Crutch Pin should move freely in the Pendulum’s slot, but not with too much slop.  Too narrow a slot will cause binding friction with the Crutch Pin.  Too wide a slot will not allow the Crutch Pin to deliver the impulse to the Pendulum.  With loss of this impulse from the Crutch Pin the clock will stop.

 So to summarize, one tests the pinion on the escape assembly with the third wheel assembly without the center wheel assembly (a with b) and then the pinion on the third wheel assembly with the center wheel assembly without the escape assembly (b with c).

 With all this done, then all three (a + b + c) should run freely in the assembled clock.  

 Also, the cannon is tested with the intermediate wheel and then the intermediate wheel is tested with the hour wheel.

 And the pallets are tested with the escape wheel (see FAQ's for more information on manually testing the pallets and escape wheel).

 And the pendulum is tested with the crutch assembly of the pallets.

 The more Depthing and testing that is done during assembly the better chance that the clock will continue to tick with the first gentle push of the pendulum.

 Remember also that changes in humidity can affect these wooden clocks.  With high humidity the wood can swell and stop the clock.  In very humid conditions I simply do nothing.  It is best to do nothing because as the atmospheric conditions change the clock will begin running well again.  The Woodworker’s Hygrometer is an excellent kinetic sculpture for detecting these changes in humidity.


Balancing the Pallets, Escape Wheel and Pendulum

Bill C asks:  How do you time the escape wheel 
and the pallet to the crutch and pendulum bob? This would help me set the pallet on the escape wheel and to know if the pendulum bob should be plum to vertical level.  Thanks for your help.

Aloha Bill, you are correct, the three components, pallets, escape wheel and pendulum, all need to be adjusted to each other to have the clock run correctly. 

First start with rounding and balancing the wheel, and then go to setting the pallets to the escape wheel.  You'll find how to manually check the function of your pallets and escape wheel in the FAQ section of my site.  Links to this, and more, are at the bottom of my main page. 

Once you have a round escape wheel and have tested that the pallets work around it a full 360* (I usually go around multiple times just to be sure), then you can set the pendulum to the pallets so that you get a good, strong, even tick-tock. 

You mention a vertical, plumb pendulum rod...that's not the way pallets are set, however I can give you a little hint to what it should look like...with the pendulum stopped, one of the escape teeth should be resting about halfway up the pallet face.  I stopped my Simplicity this morning to take this picture for you. 

When you move the pendulum to free the escape tooth, the other escape tooth should come into contact with the other pallet face in about the same location when the pendulum is at rest.  On a round escape wheel with nicely made pallets, the tooth should be at rest in about the same position on this second pallet face as on the first pallet face. 

Rounding the escape wheel to its center arbor is important.  I mount my escape wheel on a board with an upright rod in the wheel's center hole and clamp that to my sander.  Find the lowest tooth on the escape wheel and turn the wheel so all the teeth are sanded to that height.  Or, better yet, if you have left the paper pattern on the escape wheel, turn the escape wheel, sanding around the wheel so that the black line on the pattern just barely disappears.  Now we know that all the teeth are the same height with respect to the center arbor hole. 

Balancing the wheels is important also, and a balanced wheel is most important at the escape wheel.  Stick a rod in the arbor hole of the wheel assembly and the low side is the heavy side.  Lighten it by drilling or sanding away some of the back of the wheel, or adjusting the size of the wheel's cut out design by sanding some away. 

The photo I'm including I have named "Simplicity after 15 years".  My Simplicity is actually older than that but I've lost track.  In addition to the pallet/tooth positioning, what I also wanted you to notice in this picture is the amount of wear on the pallets and escape wheel teeth after the clock has been running consistently, every day for more than 15 years.  Take a close look...that's right...none! 

I was just sitting here thinking...Simplicity ticks once per second, or 3600 times an hour, times 24 hour, times 365 days a year for 15 years - that is well over 473 million ticks and tocks.  No sign of wear, and never a problem...wow! 

Pretty amazing.  I have a Big Smile on my face right now!  That Simplicity looks like it should still have another two or three centuries of good running left in it. 

I hope you love your clock just as much. 

Enjoy!  Aloha.  Clayton


Tooth Surface Finish

SwingTime Teeth
Spray lacquer is the only thing I'll use on teeth, and even at that I try to avoid getting too much into the tooth surfaces.  I spray from the center of the wheel out and try to avoid the tooth surfaces. 

We did some testing on the Weird Gears Shark Bait.  It is a hand operated kinetic sculpture.  We tested without any finish, with finish sprayed from the center, and then with finish sprayed into the tooth surfaces.  The last was a bad idea.  Finish on the tooth surfaces greatly increased internal friction.  It takes up space and also fluffs up the wood making for excessive internal friction.

It is best to avoid any finish on the tooth surfaces, but if you must, use spray lacquer lightly.  It dries hard, but still, on humid days it is subject to moisture in the air that will make it tacky.

Conclusion: finish on the tooth surfaces is just not worth it.