Planetary Gear Clock
-
- Vectric Wizard
- Posts: 697
- Joined: Sun Jun 16, 2013 4:40 am
- Model of CNC Machine: Home Built 4-axis Router
- Location: Fort Collins, CO
Planetary Gear Clock
This is a project that has been sitting unfinished for 6 years. It started out with the idea to build a fully wooden wall clock without rotating axles or bearings, using a differential planetary gear set (a.k.a. Wolfrom Gear). FWIW, the gears are not using the typical involute shape but cylindrical shaped teeth to allow for an easier rolling self supporting configuration.
While that worked reasonably well, the intent was to use a 2-second pendulum with two pawls to drive the serrated seconds ring but I never got that to work reliably. The wooden gears just have too much friction and adjusting the 4-foot-long pendulum got fussy.
I finally gave in and dropped the pendulum idea, using instead a small synchronous gear motor that drives the seconds ring with precisely 3 rpm derived from the 60Hz mains frequency.
Finished clock: Cutting the gears: Components finished: Gear set back side: Gear set front side: Short Video:
https://youtu.be/6ij7_hXSDpM
While that worked reasonably well, the intent was to use a 2-second pendulum with two pawls to drive the serrated seconds ring but I never got that to work reliably. The wooden gears just have too much friction and adjusting the 4-foot-long pendulum got fussy.
I finally gave in and dropped the pendulum idea, using instead a small synchronous gear motor that drives the seconds ring with precisely 3 rpm derived from the 60Hz mains frequency.
Finished clock: Cutting the gears: Components finished: Gear set back side: Gear set front side: Short Video:
https://youtu.be/6ij7_hXSDpM
Puzzle, Finger Joint, Maze and Guilloche freeware at https://fabrikisto.com/tailmaker-software/
- jfederer
- Vectric Wizard
- Posts: 364
- Joined: Tue Nov 27, 2018 1:09 am
- Model of CNC Machine: CanCam D23M
- Location: Horton Township Ontario Canada
- Contact:
Re: Planetary Gear Clock
Wow! And here am I, tackling Clayton Boyer's "Solaris" and thinking it's complex!
Joe Federer
www.fabrikisto.com incl. Tailmaker software
www.federer.ca
www.fabrikisto.com incl. Tailmaker software
www.federer.ca
- TReischl
- Vectric Wizard
- Posts: 4576
- Joined: Thu Jan 18, 2007 6:04 pm
- Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
- Location: Leland NC
Re: Planetary Gear Clock
Oooooo, that is NICE!
"If you see a good fight, get in it." Dr. Vernon Johns
- TomWS
- Vectric Wizard
- Posts: 350
- Joined: Sat Mar 06, 2021 11:06 pm
- Model of CNC Machine: OB Lead 1010, Mach3; OB C-Beam 1060 grbl
Re: Planetary Gear Clock
Very nice job! It looks beautiful AND interesting!
-
- Vectric Wizard
- Posts: 697
- Joined: Sun Jun 16, 2013 4:40 am
- Model of CNC Machine: Home Built 4-axis Router
- Location: Fort Collins, CO
Re: Planetary Gear Clock
I think it is less "complex" to make than the Solaris. After all, just a handful of gear triplets in a shallow assembly.
Admittedly it took me about 50 times more to envision and design that thing than to build it. While you can easily calculate the resulting gear ratio of a Wolfrom gadget from the gear set's teeth numbers I don't know a way to directly calculate the teeth numbers for a targeted gear ratio. I ended up writing a program to just figure that by trying out the millions of possibilities given some mechanical and dimensional constraints. I used 1:12 for the hours hand and 1:30 for the minutes hand. I did not find any combination to create a 1:60 Wolfrom gear. For that reason, the seconds ring has two 0-59 seconds halfs.
Puzzle, Finger Joint, Maze and Guilloche freeware at https://fabrikisto.com/tailmaker-software/
- Creation in Wood
- Vectric Wizard
- Posts: 856
- Joined: Thu May 28, 2015 8:58 pm
- Model of CNC Machine: Legacy Maverick ATC 4x8 CNC
- Location: Monument, Colorado USA
- Leo
- Vectric Wizard
- Posts: 4082
- Joined: Sat Jul 14, 2007 3:02 am
- Model of CNC Machine: 1300 x 1300 x 254 Chinese Made
- Location: East Freetown, Ma.
- Contact:
Re: Planetary Gear Clock
LOVE IT!!!
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC
-
- Vectric Craftsman
- Posts: 245
- Joined: Thu Jan 02, 2014 4:34 am
- Model of CNC Machine: Home built cnc router using Masso G3.
Re: Planetary Gear Clock
Another interesting time piece Tailmaker.
I think your move to a synchronous motor was a good one.
A few years ago I made a wooden Numerchron clock for my niece and discovered just how good the synchronous motors were at getting a reliable tick over.
I think your move to a synchronous motor was a good one.
A few years ago I made a wooden Numerchron clock for my niece and discovered just how good the synchronous motors were at getting a reliable tick over.
-
- Vectric Craftsman
- Posts: 285
- Joined: Mon Dec 01, 2014 3:53 pm
- Model of CNC Machine: Homemade
Re: Planetary Gear Clock
Splendid.
Re: Planetary Gear Clock
This is exactly what I've been looking for. Did you use the gear maker gadget? Is there a CRV file available?
-
- Vectric Wizard
- Posts: 697
- Joined: Sun Jun 16, 2013 4:40 am
- Model of CNC Machine: Home Built 4-axis Router
- Location: Fort Collins, CO
Re: Planetary Gear Clock
No, I did not use the gearmaker gadget (neither M. Wandel's GearGenerator). These make involute gears that are good for power transmission and low friction loss. The self-supporting gears of my clock need however a constant contact engagement so that they also act themselves as bearings. That was accomplished using gears with cylindrical tooth shapes. Disadvantage of this type of gear is higher friction and the need for very precise machining.
That gear design can be done manually with usual 2d-drawing tools but is a bit cumbersome. So I wrote a little BASIC program to directly generate the g-code for the gear teeth. For that reason I only have .crv files for the functional shapes that are not the gear teeth (holes, cutouts etc.). For the gears I may still have the g-code using a 2mm bit but trying to build another clock with these files would probably be difficult and subject to some failed experiments.
Puzzle, Finger Joint, Maze and Guilloche freeware at https://fabrikisto.com/tailmaker-software/
Re: Planetary Gear Clock
Neat. Thanks.