Magnet Shift Repair Solved...for me that is.

13

Comments

  • xschopxschop Posts: 1,970
    Made another more precision Pole-piece removal and centering tool. 0.996 ID and 1.299 OD....

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  • BlueBirdMusicBlueBirdMusic Registered User Posts: 1,386
    xschop, Elon Musk could use your talents.
    If the telephone doesn't ring ......... it's me
    Harry / Marietta Georgia
  • xschopxschop Posts: 1,970
    2nd thought, maybe Elon can send one of his engineers to help set up this Kegerator....

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  • GardenstaterGardenstater Posts: 1,663
    By George I think he's done it!
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • xschopxschop Posts: 1,970
    By George I think he's done it!

    Indeed, the Kegerator is setting at 35 degrees and the fireworks are already on.
  • xschopxschop Posts: 1,970
    edited July 2020
    I'll update the drawing when I get a chance. I'm going to recess the top ID of the jig to recess and hold the magnet when it is being used as the dead-blow removal of magnet from pole-piece.

    This set is already spoken for by another member and I have ordered enough material to make only 9 more sets. I'll start a for sale thread and it will be 1st come first served.
    Post edited by xschop on
  • lawdogglawdogg Posts: 388
    I love it when a plan comes together. Nice work.
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
  • lawdogg wrote: »
    I love it when a plan comes together. Nice work.

    Go ahead and get one for yourself lawdogg
  • audioluvraudioluvr Posts: 3,017
    xschop wrote: »
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    I love the granite base! Solid! ;)
    Cambridge Audio 851N Streamer/DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded
    Wireworld Silver Eclipse IC's and speaker cables
  • xschopxschop Posts: 1,970
    Is anybody else finding their magnets' Inside diameter smaller than 1.282" ?

  • jdjohnjdjohn Posts: 1,788
    Am I the only one who moved to the JB Weld Steel Steel Stick for this? I think I remember Trey @VR3 recommending the Steel Stick.
    "This may not matter to you, but it does to me for various reasons, many of them illogical or irrational, but the vinyl hobby is not really logical or rational..." - member on Vinyl Engine
    "Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
    Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
  • VR3VR3 Posts: 24,118
    I used the stock before and it was easy to work with
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • jdjohnjdjohn Posts: 1,788
    Using the Steel Stick, I think a 4-point compass application is sufficient.
    "This may not matter to you, but it does to me for various reasons, many of them illogical or irrational, but the vinyl hobby is not really logical or rational..." - member on Vinyl Engine
    "Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
    Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
  • dcmeigsdcmeigs Posts: 707
    Nice work guys. I was just about to post asking for advice on reassembling a MW 7009 I have apart on the bench when I saw this thread. It looks like you have it covered in detail here. Much appreciated.
    The world is full of answers, some are right and some are wrong. - Neil Young
  • xschopxschop Posts: 1,970
    dcmeigs wrote: »
    Nice work guys. I was just about to post asking for advice on reassembling a MW 7009 I have apart on the bench when I saw this thread. It looks like you have it covered in detail here. Much appreciated.

    Post magnet and pole-piece dimensions if you can.
  • dcmeigsdcmeigs Posts: 707
    edited August 2020
    These are different animals I’m afraid. Check out the photos. The basket has a base or flange attached with 4 rivets. The pole piece has two magnets. The flange OD is 3.6 inches, somewhat larger than you’re dealing with.

    The Pole diameter is .99
    The ID of the hole in the flange is 1.08

    The annular area is the voice coil space of course.

    The larger magnet sets on the flange. For our purposes, the smaller magnet is just along for the ride.

    The large magnet OD is 3.39.

    It is glued to the pole piece which is 3.2 OD.

    I will need a jig such as yours with a 3.6 OD for the flange and a smaller OD with set screws to center the 3.2 pole piece.

    But wait! There’s MORE! The large magnet is not centered; its shifted all the way to the voice coil. It will need to be centered too. And re-epoxied.

    If you don’t want your thread jacked, I can start a fresh one.

    Thanks, Dave

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    The world is full of answers, some are right and some are wrong. - Neil Young
  • xschopxschop Posts: 1,970
    The prototype dowel came back and am re-cutting it. I will make the rest at 1.281" OD for the smallest magnets. Seems like Polk was all over the place there too....

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  • dcmeigsdcmeigs Posts: 707
    What would be your recommendation for adhesive to reattach the souround to the basket? I dislike using contact cement because it's so unforgiving.
    The world is full of answers, some are right and some are wrong. - Neil Young
  • xschopxschop Posts: 1,970
    WMG or F1 would know.
  • pitdogg2pitdogg2 Posts: 17,968
    Aleans tacky glue. On both like contact cement and let set like contact but to the point of dry, when pressed together you still have some work time. I believe it works for the spider as well..

    On rubber surrounds you may be limited to more of a contact like cement. I've not had to repair one (knock on wood) yet. At one or another the recommendation of tire repair cement was in vogue.

    I've never used Aleans on rubber it was poly foam type and it worked well.
  • lawdogglawdogg Posts: 388
    Aileen's is also my preferred adhesive to attach the surround to the basket.
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
  • pitdogg2pitdogg2 Posts: 17,968
    pitdogg2 wrote: »
    Aleans tacky glue. On both like contact cement and let set like contact but not to the point of dry, when pressed together you still have some work time. I believe it works for the spider as well..

    On rubber surrounds you may be limited to more of a contact like cement. I've not had to repair one (knock on wood) yet. At one time or another the recommendation of tire repair cement was in vogue.

    I've never used Aleans on rubber it was poly foam type and it worked well.

    Fixed it.
  • xschopxschop Posts: 1,970
    I know it works on paper cone tears.
    One of my shop speakers took a large flying metal chip awhile back. I fixed with Aileens and moved them to the top shelf.

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  • dcmeigsdcmeigs Posts: 707
    edited August 2020
    I’ve used Aleene’s with good success too, several years ago. I’ll go fetch some. I’ll also share a photo of my very low tech magnet centering method. Feel at liberty to laugh. The 18 gauge solid wire gets it in the ballpark and then I used an aluminum vice to dial it in a little after applying the epoxy. It’s going to be pretty close when none of the wires are in a bind. The Devcon 5 minute epoxy with the static mixing nozzles are perfect for injecting the epoxy between the magnet and basket. Not a very elegant solution but I expect it to work well enough.

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    The world is full of answers, some are right and some are wrong. - Neil Young
  • GardenstaterGardenstater Posts: 1,663
    Alright I can't take it any longer.......what are these wire segments I'm looking at? Surely those can't be voice coil to pole piece gap spacers (sorry for calling you Shirley). :D
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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