Page 7 of 9 FirstFirst ... 56789 LastLast
Results 61 to 70 of 84

Thread: Unique clock

  1. #61
    Join Date
    Nov 2008
    Location
    Vancouver Island
    Posts
    8,193

    Default

    "Also, the stepper motors have 32 steps per revolution with an internal gear train often stated as a 1:64 ratio, but actually the ratio is slightly less at 1:63.68395."

    Seems a bit strange. Are they not gears?

  2. #62

    Default

    Quote Originally Posted by bergerud View Post
    "Also, the stepper motors have 32 steps per revolution with an internal gear train often stated as a 1:64 ratio, but actually the ratio is slightly less at 1:63.68395."

    Seems a bit strange. Are they not gears?
    By coincidence I recently read a paper from a trade magazine that discussed this: http://static.micromo.com/media/wysi...uction_use.pdf

    If you use gear ratios with an integer ratio, say 3:1, for example a 10 tooth spur with a 30 tooth pinion, the same sets of gear teeth will constantly mesh. If there is a defect in one of the teeth on one gear, it will cause wear in the same spot on the companion gear.
    Click image for larger version. 

Name:	integer.PNG 
Views:	24 
Size:	10.1 KB 
ID:	78823

    If you use a non-integer ratio, the wear will be more evenly distributed and the gear set should last longer.
    Click image for larger version. 

Name:	fraction.PNG 
Views:	27 
Size:	13.1 KB 
ID:	78824
    The stepper motor I am using has gear set pairs of the following:

    wheel pinion ratio
    32 9 3.555555556
    22 11 2.000000000
    26 9 2.888888889
    31 10 3.100000000
    63.683950617 final

    Oddly, the second set is an integer ratio. Well, I didn't design the thing; I'm just using it.
    Last edited by DickB; 12-22-2015 at 08:35 AM.

  3. #63
    Join Date
    Nov 2008
    Location
    Vancouver Island
    Posts
    8,193

    Default

    Very interesting. Thanks for the explanation.

    It still seems very strange to design a stepper motor without a final integer gear ratio.

  4. #64

    Default

    Quote Originally Posted by bergerud View Post
    It still seems very strange to design a stepper motor without a final integer gear ratio.
    I agree. I basically have to keep track of the error - the difference between the ideal 64 steps and actual 63.639.. - and add an additional step when the error is equal to or greater than 1.

  5. #65

    Default

    Design News accepted and published my metric clock Gadget Freak submission:http://www.designnews.com/author.asp… I built this clock for a customer in the UK, knowing that I would spend way more time on it than what I charged him. But it was a fun project, and I figured that it had a good chance of being accepted as a Gadget which, when published, earns a $500 stipend.

    This is my third published Gadget.
    Last edited by DickB; 12-22-2015 at 05:17 PM.

  6. #66
    Join Date
    Nov 2008
    Location
    Vancouver Island
    Posts
    8,193

    Default

    Outstanding project, write up, and presentation. Truly amazing Dick. Thanks also for educating us on metric time. I had never even heard of it before.

  7. #67

    Default

    A customer asked to have a clock made, posting this picture and story:
    Click image for larger version. 

Name:	clock tower.jpg 
Views:	39 
Size:	345.7 KB 
ID:	80539

    "My father is retiring in April 2016 after decades of working as a software engineer. He started at Digital Equipment Corp in the late 70s. The original plant overlooked the mill tower (pictured) in Maynard, Massachusetts. At the employee's 20 year anniversary with the company they got a mantle clock with a small replica of the mill in it. Digital equip Corp was sold 3 months before my dad got "his clock." I'd love to be able to give him what he earned so many years ago... My mom says she thought the clock was metal in glass, my dad appreciates natural materials so I think it would look amazing in wood."

    I said I could do it, although I wasn't sure how I was going to fabricate the bell tower on top.

    Later, she found a photo of one of the original clocks:
    Click image for larger version. 

Name:	clock.JPG 
Views:	52 
Size:	30.0 KB 
ID:	80540

    Good - no bell tower!

    I just finished the clock today:
    Click image for larger version. 

Name:	20160409_112358444.jpg 
Views:	61 
Size:	1.46 MB 
ID:	80541

    The customer is going to add a small metal plaque.

    I designed the clock using several rectangular carve regions and the 3D Extrude and Sweep tools. I did use my table and band saws to make the miters and a few other cuts. There are 14 pieces to the clock and three clock movements.

  8. #68
    Join Date
    Apr 2014
    Location
    Texas
    Posts
    2,877

    Default

    Very cool clock.

  9. #69
    Join Date
    Feb 2008
    Location
    Tucson, Arizona
    Posts
    2,401

    Default

    Time for you to go grasshopper!
    Steve

  10. #70
    Join Date
    Sep 2008
    Location
    Nuevo, CA
    Posts
    1,854

    Default

    Beautiful clock, but does it have wooden gears?
    Clint
    CarveWright StartU team member
    Web Site WWW.clintscustomcarving.com

Page 7 of 9 FirstFirst ... 56789 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •