This clock is based on Chapter 24 “Some Hints on Making a Regulator” of the book “The Modern Clock”, first printed in 1905 and reprinted by Arlington Book Company in 1984. The book is written by Ward L. Goodrich.
I have read the book from cover to cover a couple of times and specific chapters or passages over and over as they relate to and help me in the design and construction of wooden clocks.
The book is “A study of time keeping mechanism; its construction, regulation and repair”. That’s the byline on the flyleaf and the book lives up to its promise. He discusses clock construction, and problems discussed vary from a compensated pendulum to various escape mechanisms and ends up by describing the clockmakers goal - to have a very good “regulator” clock. This is the clock by which all other clocks in the watchmakers shop are compared too. Although that is not the intended use for the one I am building here but rather to answer the question “How would a ‘regulator’ type mechanism express itself in wood?”
Today with quartz time pieces the idea of a “regulator” is somewhat lost.
My challenge here is to see if I can use Goodrich’s writings to make an “accurate” wooden wheeled clock. Here is the story on my effort.
The overview plan of the clock. The idea of a regulator is simplicity and so the gear ratios are designed so that there is no time train. The hands turn on the gears of the running train.
The Layout of the gears is slightly altered from Goodrich’s. He had the great wheel mounted off to the left to keep the weights away from the pendulum. I opted to run two weights on pulleys to do this.
Goodrich recommends 6 spokes for the extra rigidity they provide. This is probably not necessary for wood but is in keeping with the original
The escape wheel is a 30 tooth unit that I cut out of 1/2 in. baltic birch. The wheel is quite small and I may have to enlarge it - time will tell
I decided that the small escape wheel was pushing my skill too far. I went back to the drawing board and designed this Graham escapement with 30 teeth. It works well on the depthing tool.
The great and first wheels are identical 144 tooth wheels. I have used a round gullet on the tooth design so that I could drill them and simplify cutting and improve accuracy.
Each of the 144 gullet holes were center punched with an optical center punch to help the bit hit center.
After the teeth are all cut I sand each tooth with 400 grit sandpaper to make sure the profile is true to the line
Let’s see the number of teeth to sand is - 144 plus 144 plus 96 plus 90 plus 48 (pinions) = 522 in total.
Don’t think about the number - just sand.
The first wheel and pinion mounted on the depthing tool just to see how they match. It turns very smoothly, but is quite sensitive to depthing. Hmmmm
Although the pinion “depths” fine on the wheel, there is very little extra room in the gullets of the pinion. I may redesign this one.
These pinions are interchangeable because the module is exactly the same. The difference is that the one on the right has twice the dedundum giving an easier depthing.
This wheel - pinion pair turns a little smoother that the original because the depthing is slightly better.
As the wheels and pinions are constructed I place them on the fame layout. The frame design is not finalized at this point only the wheel positions
The wheels are all cut at this point and this is the spacial layout. The “blanks” for the front and back have also been cut out and the pivot holes drilled.
How do I get rid of all the little “hairs” that plague my work!!@
I lay out the gears on the full size plan.
The gears are mounted in the frame to check for placement and get a preview of the finished unit.
Cutting out the word “REGULATOR” takes patience. I am pleased with the overall proportion of the unit.
All arbors are given brass bushings whose length is twice the diameter of the arbor.
The bushings are chamfered on the inside and outside of the ends and then the interior is “polished” with 1/8” doweling that has some pumice applied. Final cleaning is with a pipe cleaner
There are some problems. First the second hand goes clockwise OK. One wheel is skipped and the minute hand goes clockwise. But the hour hand is on the next wheel and therefore goes counter.
There is a 2nd problem. The hour wheel has a 12 leaf pinion and the great wheel 144 teeth for a 12 to 1 reduction. The hour wheel “uses” 24 pinion leaves per day. So...
The great wheel has 144 / 24 - 6 days to complete one revolution. The design therefore was to run about 2 months per winding. The amount of weight required is prohibitive for wood!!.
Although I could get the train to run. The ratios were such as to provide a 16 day run. The Great wheel was not up to the weight and strain and here is the result.
By turfing the original great wheel and increasing the winding drum to 3 inches in diameter I now have a 30 hour movement that works.
The gears nest nicely and the plates are 2.5” apart. Although all the arbors are 1/8” steel rod the positioning spaces on each arbor are baltic birch plywood
The very large winding drum was calculated to provide a 30 hour movement - nothing else made much sense.
The “finished product” and that’s in quotes because the frame needs to be redesigned and redone to match the reduction of one gear in the running train.
Since finding a home on my wall of clocks and putting the “Regulator” into beat - I have had some ideas on how to put the fourth wheel and pinion back into the train. I don’t need to have the clock run a month but would like to match Goodrich’s plan.
The normal 1/8 inch Baltic Birch that I can obtain in my part of the world is a 3 ply wood and most of the time that is more that adequate.
From the hobby shop I can also obtain baltic birch plywood BUT it is 5 ply. Naturally it is a lot more expensive and only comes in small sheets. I have used this material to make escape wheels with good success.
The largest sheets in the hobby store are 12” by 24” and the options at those dimensions are limited. In the 1/8” - 5 ply I was only able to get it in 6” by 12”
For the pinion which only measures less than one inch diameter - I now have a blank that has 40 plies in one inch thickness. Oops! If you count you will see I have glued up 9 for 45 plies and 1 1/8” thickness
The 1/2” ply has 9 plies. Since I want a 1” wheel I am hoping that 18 plies will have enough strength to do the job. If not I’ll have to wait until I can get big enough 1/8” sheets and then I’ll have the 40 plies again for the wheel.
The 1/2” material was glued up with one at a 45º angle to the other to maximize the grain variation and its strength
I drilled 1/32” holes in the gullets for relief and to avoid trying to accurately turn the blank on the scroll saw. It worked really very well. I kept the “blank” large to make it easier to handle and save fingers.
The finished pinion is actually 1 1/8” and 45 plies.
The gullet hole was located with an optical center punch and drilled before starting to saw the teeth.
The finished set on the depthing tool. The set turns smooth as silk.
Now if it is just strong enough to support a months worth of weight!
Well here it is - put back together with the fourth wheel installed. I applied 13 pounds of weight and the “click” broke. The amount of weight necessary for a month long type clock is frightening!!
Time to re-evaluate. q
Its a qualified success!
The newly cut 1” by 45 ply pinion and the 1” by 18 ply great wheel have not failed under 29 pounds of weight. Unfortunately although it will run on 29 pounds it will not do so continuously.
I dislike testing thing to failure.
The click wheel is made of aluminum since the previous ply wheel sheared off.
Likewise the click itself is made of aluminum in order to support the weight.
The driven pinion is mounted to the second wheel.
The drive wheel has been redesigned to 72 teeth from 144 and with the same 12 leaf pinion the ratio has gone from 12:1 down to 6:1.
Reassembled and back up on the wall with the 72 tooth great wheel. It will now run for 8 days between windings.
Once the running wieght was c learly established I cast them in lead with “R 2007” cast into them
This is how is looks on my wall ........
........ at least for today