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Problems with servos — Parallax Forums

Problems with servos

ArchiverArchiver Posts: 46,084
edited 2000-08-28 16:31 in General Discussion
Hi there,

I'm having a stupid amount of trouble getting the back of the Futaba S148 servos
off. I've
bent two screwdrivers and given myself a massive blister in the process...any
tips? [noparse]:)[/noparse]
This is for the Growbot package, by the way.

Regards,

James.

- James Matthews
Generation5: http://www.generation5.org/
"...At the forefront of Artificial Intelligence..."

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 14:44
    Mr. James Matthews,

    I've not had a chance to investigate the Allegro stuff from your last
    email, however, this appears to be a LIFE SAVER! Hopefully, this can
    free-up my BS2 from controlling the servo and allow it to accomplish other
    things. (HORRAY!!!) As for the problem with disassembling the servo motor
    (not sure if mine is the same, however, know it is a Fubata model from
    Parallax) make sure you remove all four stainless screws completely from the
    bottom, then make sure you remove the black screw from the opposite side
    (top) and remove the "plus shaped dog" so the top of the case can come off.
    After looking at mine it occured to me that you might be trying to
    disassemble it about 1/4" from the bottom (stainless screws) and instead
    mine comes apart about 1/2" from the top (black screw and plus shaped dog).
    If I'm of no use and eventually you do figure it out, please let me know
    what the problem was.

    Sincerely,

    David Fixemer

    Original Message
    From: James Matthews [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=kbTl4o333KER52jtfZioQ3UeJJixo5FTOlscSkLYy9IkBdqvOOeSLRtXiFzKWGupxYoJJxvHoiI7AU25gwNFALF9mA]jmatthews@g...[/url
    Sent: Thursday, August 24, 2000 8:32 AM
    To: basicstamps@egroups.com
    Subject: [noparse][[/noparse]basicstamps] Problems with servos


    Hi there,

    I'm having a stupid amount of trouble getting the back of the Futaba S148
    servos off. I've
    bent two screwdrivers and given myself a massive blister in the
    process...any tips? [noparse]:)[/noparse]
    This is for the Growbot package, by the way.

    Regards,

    James.

    - James Matthews
    Generation5: http://www.generation5.org/
    "...At the forefront of Artificial Intelligence..."
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 15:05
    At 02:31 PM 8/24/00 +0100, James wrote:
    >
    >I'm having a stupid amount of trouble getting the back of the Futaba S148
    servos off. I've
    >bent two screwdrivers and given myself a massive blister in the
    process...any tips? [noparse]:)[/noparse]
    >This is for the Growbot package, by the way.

    Make sure the servo horn is off (unscrew it) and the four screws holding
    the case together are out. It should then come apart very easily.

    Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 15:08
    Sorry, I didn't clarify -- I cannot remove the screws on the back of the servo.
    The servo
    horn is no trouble to get off, but the back four are impossible!

    James.

    Original Message
    From: <orthner@s...>
    To: <basicstamps@egroups.com>
    Sent: Thursday, August 24, 2000 3:05 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Problems with servos


    > At 02:31 PM 8/24/00 +0100, James wrote:
    > >
    > >I'm having a stupid amount of trouble getting the back of the Futaba S148
    > servos off. I've
    > >bent two screwdrivers and given myself a massive blister in the
    > process...any tips? [noparse]:)[/noparse]
    > >This is for the Growbot package, by the way.
    >
    > Make sure the servo horn is off (unscrew it) and the four screws holding
    > the case together are out. It should then come apart very easily.
    >
    > Duncan
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 19:12
    Some FUTABA servos have special screws with a very high pitch threads.
    ACJacques

    James Matthews wrote:
    >
    > Hi there,
    >
    > I'm having a stupid amount of trouble getting the back of the Futaba S148
    servos off. I've
    > bent two screwdrivers and given myself a massive blister in the process...any
    tips? [noparse]:)[/noparse]
    > This is for the Growbot package, by the way.
    >
    > Regards,
    >
    > James.
    >
    > - James Matthews
    > Generation5: http://www.generation5.org/
    > "...At the forefront of Artificial Intelligence..."
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 19:56
    Does that mean they are *really* hard to get out? [noparse]:)[/noparse]...mine simply don't budge.
    What do I
    have to do to get them out?

    James.



    > Some FUTABA servos have special screws with a very high pitch threads.
    > ACJacques
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 21:12
    James:
    Use a new, sharp screwdriver. There is stuff called "Screwgrab", or
    something similar. It is just a water-based suspension of carbide particles
    in a container like Elmers white glue. You apply it to the stubborn
    screwhead, and it provides great improvement in gripping the screw without
    the screwdriver slipping . Sears Hardware, (and probably others), has it.
    I have used it often with great success.

    HTH,
    Ray McArthur

    Original Message
    From: James Matthews <jmatthews@g...>
    To: <basicstamps@egroups.com>
    Sent: Thursday, August 24, 2000 2:56 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Problems with servos


    > Does that mean they are *really* hard to get out? [noparse]:)[/noparse]...mine simply don't
    budge. What do I
    > have to do to get them out?
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-24 22:54
    > Does that mean they are *really* hard to get out? [noparse]:)[/noparse]...mine simply don't
    > budge. What do I have to do to get them out?

    At this point, I guess it's worth checking: You are trying to turn the
    screw *counter-clockwise* -right ?


    Mark Hillier
    President, HVW Technologies Inc.
    Mark@H...
    Tel[noparse]:([/noparse]403)730-8603 Fax[noparse]:([/noparse]403)730-8903
    Visit our web site: http://www.hvwtech.com
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-25 13:08
    > Sorry, I didn't clarify -- I cannot remove the screws on the back of
    > the servo. The servo horn is no trouble to get off, but the back four
    > are impossible!
    >
    > James.
    >
    Japenese + head screws use a different angle which often cause
    common US Phillips screw drivers to not get a good grip or strip
    the head. A Hobby store will have correct fitting
    screwdrivers(Tamiya) or better hardware stores.

    Mike DeMetz N9GEZ
    Elkhart, IN
    mailto:miked@e...
    http://www.elkhart.net/~miked
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-25 14:47
    I have a couple of older futaba servos that have a sheet metal type screw in
    them. The pitch on the thread is a turn ot two per inch. If you put much down
    pressure on them when trying to remove them you cant unscrew them because of the
    screw pitch. I got all but one out by finding a screw driver that fit tightly
    and turning and putting as little pressure downward as possible. I replaced them
    with some standard ones from an old servo. This may be the same problem you
    have.





    > Does that mean they are *really* hard to get out? [noparse]:)[/noparse]...mine simply don't
    > budge. What do I have to do to get them out?

    At this point, I guess it's worth checking: You are trying to turn the
    screw *counter-clockwise* -right ?


    Mark Hillier
    President, HVW Technologies Inc.
    Mark@H...
    Tel[noparse]:([/noparse]403)730-8603 Fax[noparse]:([/noparse]403)730-8903
    Visit our web site: http://www.hvwtech.com
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-25 16:51
    Assuming the screws are into plastic casings [noparse][[/noparse]I don't
    know these servos.. ] try some heat - the issue being
    to soften but not melt the plastic - soldering iron
    tip set to below sodering temp heat sometimes works.

    This can help with Loctite in brass inserts as well.

    [noparse][[/noparse]Mark: Counter clockswise? I thought we all had digital
    displays... :-) Counter digital...]

    Good luck - don't get mad and hurt something...

    ________________________________________________________________
    YOU'RE PAYING TOO MUCH FOR THE INTERNET!
    Juno now offers FREE Internet Access!
    Try it today - there's no risk! For your FREE software, visit:
    http://dl.www.juno.com/get/tagj.
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-25 17:40
    Thank you everyone for your help.

    > Japenese + head screws use a different angle which often cause

    I bought my screwdriver set in Japan, so...[noparse];)[/noparse] ¥96 for 6 small screwdrivers, what
    a
    bargain! Probably why they're bending under pressure too.

    > Good luck - don't get mad and hurt something...

    Too late for that. Haha, my index finger has swollen up to some stupid size.
    I'll try your
    heat suggestion, thanks. I'll get the little bastards somehow.

    Regards,

    James.

    - James Matthews
    Generation5: http://www.generation5.org/
    "...At the forefront of Artificial Intelligence..."


    Original Message
    From: s premena <premzee@j...>
    To: <basicstamps@egroups.com>
    Sent: Friday, August 25, 2000 4:51 PM
    Subject: [noparse][[/noparse]basicstamps] RE:Problems with servos


    > Assuming the screws are into plastic casings [noparse][[/noparse]I don't
    > know these servos.. ] try some heat - the issue being
    > to soften but not melt the plastic - soldering iron
    > tip set to below sodering temp heat sometimes works.
    >
    > This can help with Loctite in brass inserts as well.
    >
    > [noparse][[/noparse]Mark: Counter clockswise? I thought we all had digital
    > displays... :-) Counter digital...]
    >
    > Good luck - don't get mad and hurt something...
    >
    > ________________________________________________________________
    > YOU'RE PAYING TOO MUCH FOR THE INTERNET!
    > Juno now offers FREE Internet Access!
    > Try it today - there's no risk! For your FREE software, visit:
    > http://dl.www.juno.com/get/tagj.
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-25 18:53
    James,
    If you're going to use heat to soften the plastic, do it heating
    the *screw* itself. You could likely get it hot enough to yank out by
    putting the tip of your soldering iron against the head of the screw for a
    minute. This way, you'll only melt the plastic that's right against the
    screw, not the whole case.

    Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-26 23:30
    Any other tips?...I've tried heating them w/my soldering iron, which seems to
    have an
    effect on the servo casing, but doesn't do much to remove the screw. My hands
    are a
    wreck...makes playing my guitar *quite* painful.

    I'm gonna go play with my AIBO instead.

    James.

    - James Matthews
    Generation5: http://www.generation5.org/
    "...At the forefront of Artificial Intelligence..."

    Original Message
    From: <orthner@s...>
    To: <basicstamps@egroups.com>
    Sent: Friday, August 25, 2000 6:53 PM
    Subject: Re: [noparse][[/noparse]basicstamps] RE:Problems with servos


    >
    > James,
    > If you're going to use heat to soften the plastic, do it heating
    > the *screw* itself. You could likely get it hot enough to yank out by
    > putting the tip of your soldering iron against the head of the screw for a
    > minute. This way, you'll only melt the plastic that's right against the
    > screw, not the whole case.
    >
    > Duncan
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-27 22:10
    OK - down and dirty - Drill the heads off the screws and
    pull the stub with a vise grip plier when you can get at it.

    Heat the screw till it melts out... re-thread for different
    screw later or use hose clamp around casing...

    Take Dremel tool and excavate screw head until you can
    get small vise grip plier on it. If you do get just one
    out, you may see how to get others without messing up the
    rest.

    Some of these fasteners are not screws but spiral press
    pins - you have to grip, twist and pull.

    If it turns out they are _long_ screws with a nut on the
    far end it can be a problem.

    Occasionally you'll run into a screw with a hole in the
    shaft with a push pin through that to keep it from turning.

    Heat on the screw usually melts out the plastic around without
    distorting the whole case. And perhaps the sticky screw
    secret is then revealed.

    To save your fingers trying to turn the screwdriver clamp
    a vise grip plier to the screwdriver shaft and turn it
    with the vise grip plier as a lever. While holding
    pressure on the screw with screwdiver handle. [noparse][[/noparse]wrecks the
    screwdriver shaft some].

    NOTICE - Any of the radical suggestions above can result in
    damage to the device and you'll like regret you did it once
    you see how you could have gotten them out some other way!
    On the other hand you will have learned something...

    What goes in comes out - persist [noparse][[/noparse]I've conquered thousands
    of screws!] some of the hard cases snap off the screwhead
    and leave the thread embedded. Software is so much less -
    _physical_ - good luck :-)


    >> Date: Sat, 26 Aug 2000 23:30:00 +0100
    From: "James Matthews" <jmatthews@g...>

    Any other tips?...I've tried heating them w/my soldering iron,
    which seems to have an effect on the servo casing, but doesn't
    do much to remove the screw. My hands are a wreck...makes playing
    my guitar *quite* painful.
    <<

    ________________________________________________________________
    YOU'RE PAYING TOO MUCH FOR THE INTERNET!
    Juno now offers FREE Internet Access!
    Try it today - there's no risk! For your FREE software, visit:
    http://dl.www.juno.com/get/tagj.
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-28 16:31
    My solution would be.... Use this as an unmodified servo, and go buy another
    one to modify. All this frustration isn't worth the price of a single
    replacement servo. [noparse]:o[/noparse])

    Shawn

    Original Message
    From: James Matthews [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=xaE8nC8aybuW6hsDt9ZfXWiDG_usQNVS9zTEgTu0mrWvWPrCpCZHk6orCiR32VevJ1ZQelwt6sopcfcofo0NCSE]jmatthews@g...[/url
    Sent: Saturday, August 26, 2000 3:30 PM
    To: basicstamps@egroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] RE:Problems with servos


    Any other tips?...I've tried heating them w/my soldering iron, which seems
    to have an
    effect on the servo casing, but doesn't do much to remove the screw. My
    hands are a
    wreck...makes playing my guitar *quite* painful.

    I'm gonna go play with my AIBO instead.

    James.

    - James Matthews
    Generation5: http://www.generation5.org/
    "...At the forefront of Artificial Intelligence..."

    Original Message
    From: <orthner@s...>
    To: <basicstamps@egroups.com>
    Sent: Friday, August 25, 2000 6:53 PM
    Subject: Re: [noparse][[/noparse]basicstamps] RE:Problems with servos


    >
    > James,
    > If you're going to use heat to soften the plastic, do it heating
    > the *screw* itself. You could likely get it hot enough to yank out by
    > putting the tip of your soldering iron against the head of the screw for a
    > minute. This way, you'll only melt the plastic that's right against the
    > screw, not the whole case.
    >
    > Duncan
    >
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