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  1. #21
    Quote Originally Posted by njhussey View Post
    ... whatever bearings you use will need a preload on them to stop them from skidding. ....preload them with something like bellville washers.
    As you already know, i read all yours conversation with blackburn mark an others about preloading when you was building your spindle. But everything is a little confusing to me, as English is not my language. So i draw a sketch in mspaint( 1000 words) to clear things. Simply answer to numbers with tight/loose relations between parts. For example, i think 2 and 3 are tight connections.
    Then, please explain "preload". Is that, to tightening a housing cap with housing to press outer bearing ring, or something else?
    Click image for larger version. 

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    I think it would be a great help for me and others to see all relations in one place, so thanks in advance.
    Last edited by volcano; 12-06-2017 at 01:48 PM.

  2. #22
    Things are start to get moving...
    I hook up the motor, everything works.
    Motor sound way unbalanced, make huge vibrations in mid range ( @12V ) rpms.
    But the dial tester says just a 0.01 runout???
    Click image for larger version. 

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    turn motor by ~70 degree left sims to give bigest value....( see sticker on rotor -1st pic)
    Click image for larger version. 

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    By the way this is the first time to use this dial test indicator ( just arrived ), so i think that
    maybe the tool is not precise, or i`m doing something wrong???

    Anyway, next thing is ...to build a tachometer to measure rpms...
    Cheers!

  3. #23
    It's probably not the shaft that's unbalanced but the magnets in the bell, not unusual to have big globs of glue between some magnets and not others. The DTI looks a good one so I'd say you've minimal runout on the shaft.
    Neil...

    Build log...here

  4. #24
    Actually the DTI works perfect. I borrow a second (pro one) from a friend and done some comparative test, so mine DTI works great. A very handy tool :-).
    Building housing part is at pause for now , because friend who will do it for me ( i do not have lathe...) is overloaded with jobs at the moment.
    Because of that, i decided to use my spare time to build a electronics for my future spindle. So far i figured out how to
    make an Arduino speed control. This is a only one video i find so far, that closely matches mine idea.
    https://www.youtube.com/watch?v=kYFNUQgE26E
    Arduino reads rpms from spindle with an optical sensor, and sends pwm output, so actual rpms try to match targeted one ( take a look at the video).
    This " pid " control is not designed to work with ours rc outrunner and ESC.
    But there is an Arduino servo library and a bunch of tutorials on how to conrtol ESC with Arduino.
    So it`ll be most elegant if i manage to mredge this in one project.
    When we cut some mat., spindle will try to maintain the rpm, so torque is improved. :-)
    Gain will be big (and dirt cheap) with this speed control.

    Early phase of experiment (with salvaged hadware) + Arduino...
    Click image for larger version. 

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  5. #25
    Just to say hello! Was on vacation, now i`m back. Meanwhile, all parts arrived. I`ll start building next week.
    Cheers!

  6. #26
    My "S-Pid" controller work continues.
    Made new sensor today (paper detection sensor salvaged from some old printer, copier...desoldered from its original pcb and added some resistors...) I done some fine tunings and start measuring. I compared my controller readings with
    results measured with my standalone tachometer device. Accuracy is far better then i expected. Check the picture!
    Click image for larger version. 

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    P.S. So... finding and building a good sensor is done. Accuracy of reading RPM is checked and accomplished, also. Now i will hook an real rc brushless motor instead of this pc fan.
    P.P.S. I am aware that what i wrote is far away from spindle mechanical build, but electronic is also
    a part of spindle system i want to build, and that kind of spindle speed control is presented in far more expensive rigs. Please tell me if you think i shouldn`t write about this pid controller here, and/or if you like it? Comments are most welcome.
    Cheers!

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