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Thread: Building The Magnetic Clock

  1. #11
    Join Date
    May 2006
    Posts
    8,963

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    Very nice work G.R., now that's an introduction

  2. #12
    Join Date
    Feb 2010
    Location
    Spokane
    Posts
    1,016

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    Quote Originally Posted by George_Race
    Maybe someone can comment on how, if anyway, I may have been able to do it better.
    Beautiful looking work!

    Not sure if it would be available off the shelf, but it looks to me like you would have much less chatter problems with a stub flute end mill. It looks like it is sticking out way to far.

    Dave

  3. #13

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    Hi Dave, holder is an ER13, to give you an idea of size. The bit extends about 3/4 and inch below the holder. I also have a much heavier ER25 that may have added enough extra weight to reduce the chatter a bit. But, by adjusting the feed and RPM I got it pretty quiet.
    Thanks for your comment,
    George
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  4. #14

    Default Ice Shrink and Broaching Is Done

    Today was a good day to get something done on the Magnetic Clock project.
    This morning I put the Rotor Spoke Plate in the freezer. About three hours later I removed it and pushed it into the steel Rotor Rim. When it warmed up, it seems to have a very tight fit. I guess I got lucky with the machining as the two parts fit perfectly. Here is a close up picture of the finished piece.



    Next I built the hex broach, using Weston's instructions in the Magazine.

    Here is a picture of the finished broach, from a 1/8 inch hex wrench.



    Here is a picture of the broach doing it's job on the part "D" wheel.



    And finally, here is a picture of the finished broached wheel.



    That is about as far as I go on this project until the next issue of the magazine comes in the mail. By the way, what is the publication date? Someone here must know.

    Comments and suggestions always welcomed,
    George
    Last edited by George_Race; 07-25-2012 at 12:11 PM.
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  5. #15
    Join Date
    Jan 2008
    Location
    Traverse City, MI
    Posts
    1,037

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    Quote Originally Posted by George_Race

    That is about as far as I go on this project until the next issue of the magazine comes in the mail. By the way, what is the publication date? Someone here must know.
    Hello George,

    The magazine is scheduled to print the last week in June and should start hitting mailboxes sometime in the first and second weeks of July. I'll try and get the drawing files up on the website prior to that, if that would help. BTW, great job on the clock, I've enjoyed seeing your progress.

    George

  6. #16

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    Thanks George, nice to know when to start watching for it.

    If you could drop me a line when the drawings are on the site, it would be appreciated.

    Thanks,
    George
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  7. #17

    Default Magnets All Installed

    Installing the magnets in the wheels is the last step I can do before the next issue.

    Here is a picture of the magnets all installed in the wheels.



    Putting in the magnets, with a N-S-N-S polarity around the wheels really sounds like a very easy task. Well let me tell you, not as easy as I first through. First you need a way to keep the N & S ends separate. Should be easy, take a stack of magnets and one end would all be the North end, the other would all be the South end. Going around the wheel, put a N in every other hole, then go back and put a S in the remaining holes. Sounds easy huh!

    I started by doing a couple of the small wheels. I purchased some Lock-Tite Gel Super Glue. Dispensing it in the holes was very easy and uniform due to the package it comes in. Now take the stack of magnets, push into a hole, slide it off the top of the stack, and go to the next hole and do the same. When all the way around, turn the stack over and use the other end to fill the renaming holes. Let sit for about 30 minutes and then test the polarity with a stack of magnets. Every other one should attract or repel one end of the stack as you go around the wheel. Oops, something happened, about half of them were incorrect, some N-N-N and some S-S-S. Now how in the heck could that happen?

    Move on to the next wheel. Be extra careful, hold the magnets by the same end, do the first 4, turn the stack over and do the next 4. Let set a few minutes, then test the polarity. WHAT! The first thing I found was S-S-S! Now I have two wheels that are wrong! Time to stop and come up with a sure way to make sure this does not happen again. But, what in the heck do I do to remove the magnets from the incorrect wheels? Being that the holes milled for the magnets were .125 inches (3.17mm), and the magnets were 3mm, they fit in the holes really well, with the glue filling the small surrounding gap.

    Doing a bit of quick research, I found that acetone was what was needed to dissolve the Super Glue. Went to a local store and bought a big bottle of 100% Acetone nail polish remover. Put about 1/2 and inch in a small glass bowl with a pretty tight cover, and dropped in the two pieces. Waited about three hours, no luck! Could not get the magnets to come out, being pulled on by a stack of magnets. Oh well, probably will need to machine some new wheels tomorrow!

    The next morning, went to the shop, looked into the bowl and saw 6 of the magnets stacked on top of each other! WOW it worked! Reached in and moved the wheels around and instantly had a stack of 12 magnets between my fingers! Them little things really attract each other! Incidentally, the magnets I purchased have rating of N42

    If you are curious about these super magnets, here is a great page that has everything you ever want to know about them. http://www.kjmagnetics.com/neomaginfo.asp A lot of very good reading material.

    Next, I devised a way to insure that I installed all the magnets correctly. I took a piece of black and a piece of red heat shrink tubing, about 2 inches long, just the right size to allow the magnets to slide inside. I put a stack of three into each piece of tubing, and using minimum heat shrunk the tubing enough to hold tightly to the magnets. Be careful how much heat you use, as it does not take much to demagnetize these kind of magnets. I made sure that the black piece has an exposed N pole and the red piece an exposed S pole.

    Now, setting the red tool well out of reach, I one by one picked up a single magnet and using the tool, pushed it into a hole. I used a very small pointed piece of brass rod to hold the inserted magnet in place, while sliding the tool off of the magnet. When every other hole was filled, I switched tools and repeated the process, filling the remaining holes in the wheel. As each wheel was finished, I checked each one, from the back side, using a stack of magnets to make sure the polarity of all adjoining magnets was opposite. Finally they were all installed properly! All in all it took me about 3 hours to install the magnets properly!

    Hopefully my struggle with this task will help others who attempt to build Weston's Magnetic Clock do it quicker and correctly the first time they try.
    Last edited by George_Race; 07-25-2012 at 12:13 PM.
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  8. #18

    Default The Build Continues

    Time to start the next phase of Weston's Magnetic Gear Clock. Here is the latest progress on the build. I started by importing drawing #9, the Main Frame, into CamBam. After checking the imported files dimensions against the actual drawing, it was time to start cutting metal. My first attempt was to machine a piece of .375 Alcoa Cast aluminum plate. It was a disaster! I am so used to 6061T6 I guess I have problems with anything else. On top of that, my home made CNC, although very accurate, does not take well to very heavy work, and to my home made setup, .375 is heavy work.
    So what to do? Gosh, I have lots of 6061T6 .125, how about making three pieces and using the final result like it was one! After all, there are going to be threaded holes through all the pieces, the screws will certainly hold it all together.
    So here we go with the project! The first picture shows how the Main Frame pieces were cut.


    And here is how one of the pieces looked when finished.


    And when you stack three of them together, you end up with a .375 Main Frame. Now to thread the various holes.
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  9. #19

    Default Here is the Secondary Frame

    Like the main frame, I cut three separate pieces out of .125 to achieve the goal of a .375 Secondary Frame.
    Here is how they looked being cut.


    And here is the stack of three pieces for the Secondary Frame.


    I am always impress how easy it is for the CNC to make such accurate duplicate parts. The .070 holes around the three circular areas are all precisely aligned. Looks like it is going to work!

    Looking through the drawings, I found several pieces that I could easily import and make on the mill.
    Here they are, labeled to show which parts they are.


    Looks like this is about all I can do with the CNC. Next I will be working on my lathe skills, attempting to make a bunch of round parts. More pictures and information to follow as I continue the build of Weston's Magnetic Gear Clock.
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

  10. #20

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    A little bit more was done today. Have all the threaded holes in the frames done. I then CNC cut part 28 the Intermediate Hub Bearing Spacer, and part 29 the Hour Hub Bearing Spacer. In the picture below they are in the upper right corner. Cut them with a .0625 End Mill.
    My Web Site
    www.mrrace.com
    Builder & Test Pilot N73EX

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