|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|
|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.
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.
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.
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