First Mechanical Clock Prototype Partially Working

To say that I made a functional clock is a bit of an exaggeration, but I now have made a prototype clock that can at least keep some sort of time with a pendulum.  Semi-accurate timekeeping only lasts for a few seconds, until the escapement gear goes haywire, but it’s at least similar to a clock.  Check out the video to see what I mean:

Since this is my first try at building a clock, (besides some cool electronic Hard Drive Clocks) and I did almost no research beforehand, I’m not going to call this a failure.  However, I think it might be time to “back up and punt” on this design using the lessons I’ve learned.  Here’s a few things to remember for the next clock:

Gears Are Complicated

prototype-escapement

early prototype of the clock escapement

As mentioned in my first mechanical clock post, my gear design consisted of drawing a block on top of a circle and giving it some sort of corner radii.  Given that the Machinery’s Handbook has many, many pages on their design, it might take some more thought.  Honestly, I’ll probably just use this gear generator.

Friction is a huge enemy to a properly-working clock, and malformed gears certainly can contribute to this.

Driving Gear and Pulley Considerations

inner-clock-gears-woodThe gears that I have are capable of driving from the escapement to the hour hand, however it introduces a lot of friction going in the other direction.  Better gears should take care of this, allowing me to mount my pulley on the minute or hour gear.  Right now, it’s mounted to the second gear, meaning one revolution for every minute.  That’s a lot of winding.

After a bit more poking around, and asking about this Trebuchet Clock on Youtube, I may actually add a separate driving gear to hang the pulley from.  This should work better than trying to use one of the other gears.

 

 

Third Dimension

prototype-wood-clock

prototype wood clock – notice the flashlight/weight

As shown to the right, everything is currently attached to one board.  The rods tend to flex, and seem to be slightly bent.  This is a huge issue for the escapement, and I think the reason that it runs extremely fast during part of its rotation.  Better rods (maybe brass) and a second, supporting frame should help this issue.

Proper Gear Attachment

Glue does not work to attach gears together, especially when Teflon washers are involved.  Small nails work pretty well, and I’ll probably try to pre-drill the gears for this method in the next iteration.  This should make things more precise.

Above is another video of my clock.  I’m not sure if the rod is bent, throwing the escapement gear off, or the center hole is off, but either way it doesn’t quite work correctly.


I’ll probably return to clock-making at some point, however, I feel like I’ve gotten to a good stopping place for the time being.  In the mean time, I’ve got some other really cool projects in the works or that are simply ideas now, so be sure to subscribe (upper-right sidebar) to see what comes next on JCOPro!

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21 Comments.

  1. Designing and Building a Wooden Mechanical Clock - pingback on March 19, 2013 at 7:02 am
  2. Christopher Gaul

    It seems to me that the problem with your escapement comes from the fact that your pendulum rod flexes in both axis. If we call the axis all your gear shafts point in X and the axis perpendicular to that (ie along the face of the board) Y. Then it seems like your pendulum shaft should be stiff to prevent flexing in the X direction. It seems that the oscillations in the X direction are flexing the escapement causing the gear tooth jumping.
    Maybe if the pendulum was attached with a piece of flat bar rod instead of a round rod. With the flat face aligned to the X axis. (ie so it looks skinny when looking down the shafts of the gears and wide when looking down the face of the wood)

    Anyway, just my two cents worth on your very cool and ambitious project. Good luck!

    • Thanks for your thoughts (and thanks for reading)! What I’m thinking at this point is to further brace everything by adding a second cutout supporting board in front of everything. Should have the effect of what you talk about in your other comment!

  3. Christopher Gaul

    …either that or brace the now free end of the escapement shaft.

  4. I have not yet made a clock but here are some plans you might want to look at, unless you like trying out your own design http://www.woodenclocks.co.uk/downloads.html

    There was another site, the guy sent me some dxf files to use on my CNC machine, but it appears to have shut down (I think). Look at these too http://lisaboyer.com/Claytonsite/Claytonsite1.htm

    • Thanks Rich! I hadn’t seen any free clock plans yet, so that’s great. I’ll have to study them to see if there’s anything I need to correct/improve based on his ideas.

  5. I have some dxfs that one of these guys sent me some years ago, I can shoot them to you if you want. I never did anything with them, and not sure now who sent them, but easy enough to turn them into gcode. They might be the same as one of these sites.

    Not sure how to send them to you on the site here.

  6. Making inspiration: the Strandbeest four or more leg walker - pingback on May 24, 2013 at 8:56 am
  7. EEWeb Site of the Day - pingback on October 24, 2013 at 9:28 pm
  8. what is diameter of the rod and demsion of the gear and diameter of the gear. how much weight is please tell

  9. please tell me which gear for hour and minute in vedios

    • Hi Mayank,

      The furthest large gear to the left in the video is for hours, the rightmost is for seconds. I think the minute gear is the second from the left, but it may be the third, I’m not entirely sure.

  10. actualy i dont understand because center point is same for mintue or hour

    • The minute “hand” is one gear, the hour “hand” is another gear. The “clock” I built doesn’t work with a single axis like with most models that you see.

  11. whats the weight of the pendulum any matter weight in pendulum?

  12. if you provide the report

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