I was given the plans for this clock which were originally drawn up by Nick Andronis by a friend quite a while ago. I first set out on this journey to build a clock only to realize how little I knew about clocks or wood.
The inspiration clock had a hour/minute and seconds dial with a short run time. What I wanted was a clock with a symmetrical dial and a day of the month dial. The run time was increased by maximizing the weight run length and minimizing the bush bearing friction. The original run time design was seven days but could not be achieved with wooden bush bearings.
Step 1: Prepare to Become Needy
Things you will need:
Wood (at least two different types if you want a contrast.) Yes I know this should be a no brainer. However, you must remember that every piece will require at least some material. Wood is not a cheap medium to work in and you WILL make mistakes. Do not get chemically treated, unseasoned or green wood or expect to walk into your backyard for trees.
Tape measure: Prepare to measure three times if not more and cut once. Again, have extra wood.
Micrometer. Don't be cheap, buy a professional, digital metal micrometer. You'll thank me later.
Paper: I went to a local art store and bought two rolls of kids art paper, it is good for calculations, lists, templates and beating on things during the occasional temper tantrum.
Glue: Don't skimp, buy wood glue or something similar. Something that you can wipe off if/ when you make mistakes.
Wood clamps: Buy at least 4 in several sizes, they don't wear out easily but you never seem to have enough.
Stain or linseed oil: Decide what you are going to use, buy a gallon and a half, mix it together in a 5 gallon bucket before use, the batches don't always match.
Shellac, lacquer or sealant: Bring out the shine in your work.
Sandpaper: Get 100-1400 wet/ dry, a sanding block, an electric sander and be prepared to take a lot of time.
Drill press: The parts have to be precise or they won't fit or work.
Hand drill: Some pieces are too large or small to hold on a press.
Table, miter or chop saw: For rough, straight cuts or long lengths.
Band or Jig saw: bigger radius cuts, circles or shapes can be achieved with this.
Hack saw: Little, tiny curves cannot be cut precisely enough on a band saw.
000 Steel Wool: if you sand with this last you will get a super shiny finish.
Lead: This hazardous material is used for the counter weights. I found mine at a scrap yard and they were more than happy to give it to me. Worse comes to worse you could always melt down old tire weights. It will have to be a lot of them, and please... No stealing. Steel can also be used but you will have to have it machined.
Step 2: I've Got Wood!
Hardwoods are in a group of trees that have broad leaves, produce a fruit or nut, and generally go dormant in the winter. The United State's have temperate climates produce forests with hundreds of various hardwood trees that share certain biological characteristics. Although oak, maple and cherry are all hardwoods, they are different species. All together the hardwood species represent 40 percent of trees here.
Taking all of this into consideration I decided to use cherry as my primary and red oak as the accent pieces. Well, that and the cost of materials.
You need to really look at all factors before deciding for your own project.
Step 3: Size Matters
The size of the clock was determined by the largest piece of wood that could purchase. The size of every clock component is a ratio of the escapement diameter. The metric units are considerably easier to measure than the standard measurements. The 180mm diameter by 4mm thick escapement required a dimensional stability of less than 0.5mm.
To minimize warping the escapement was solved by polishing the cherrywood with a round sanding disk and heating the wood until the resin melted and the moisture evaporated. Heating the wood also increased the hardness and the contrast in the wood grain. By clamping the wood and allowing it to cool over several days the wood will stabilize and stops warping. This procedure must be repeated in order to thickness the escapement down from 8mm to 4mm in 1mm steps. To relieve internal stresses the escapement must be roughed out before this. Once the required thickness has been achieved then the escapement hammers and ribs can be finished off.
I found a local wood kiln, which is what I recommend unless you want to build one.
****Word of warning: do not try to do this over an open flame or in your oven. The wood smells awesome, the beat down your spouse will issue is not. These are written in blood! Learn from my mistakes people!****
Step 4: Three Part Harmony
One of the lessons learnt from complex engineering systems is to build the most difficult bit first.
If you cannot build a clock with only a second hand then there was no point continuing with the project.
A three component clock is assembled from the escapement, simple rocker and a pendulum rod.
Calculations indicate that a two second time constant required a 1 meter pendulum. So in theory the clock should work if the time constant of a pendulum is a function of the distance between the pivot point and the center of gravity. The mass of pendulum rod shifts the center of gravity closer to the pivot point.
Step 5: Pretty
These pieces came together.
Step 6: Gears
A computer laser printer was used to generate gear templates that were printed on adhesive paper. Then I drilled out the center of each gear using standard drill bits and finished each by hand. ***Warning*** Drilling straight hole across the grain is difficult. The hole centers were marked with a fine cross on the laser printer templates. I first marked the centers of each hole with a pick then used that as my holes beginning. Gears were clamped to a table vice on the drill press and then drilled with a 3mm drill bit. Then I swapped the fine drill bit for the correct size drill bit. This process produced precision holes but was very labor intensive.
Step 7: How Do I Look?
The finished products
Step 8: Separation Anxiety
I made the face and encasement pieces in many parts which I then glued together. Again, labor intensive but worth it.
Step 9: Done and Done
Large pieces of quality cherrywood were expensive so the clock dials had to be manufactured by laminating 12 pieces of wood. Looks easier than it was.
Step 10: It's the Little Things
There are many, many carriers, bolts, nuts and pins. Each made by hand.
Step 11: Now You See Me.
Remember, test fit everything. The inside before I assembled everything.
Step 12: Weighty
The weights have to be figured or your clock won't function properly. There are websites to help you with this.
Step 13: Show and Tell
Step 14: Reunited
Step 15: And It Feels So Good
Step 16: Supporting Cast
Step 17: Legs
Step 18: Mounting
Step 19: Done
The clearance between the gear teeth had to be adjusted to allow the clock to run free. Slight density differences of wood made the load unbalanced. The drive shafts were not at right angles to the gear so the clock would stop every few hours. All of this caused the clock to stop at certain times of the day.
The gears can be balanced by spinning the gears in the clock frame. If the gear stopped in the same place then wood should be removed from the bottom of the gear.
The time constant of the clock was finally set by adjusting the pendulum weight screw. Once the clock time constant is set the clock will run for two days with an accuracy of better than five seconds per day.