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Breaking Aluminum Couplers - 6.5-10mm

Discussion in 'CNC Mills/Routers' started by Dave Dreher, Jan 22, 2022.

  1. Dave Dreher

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    Hello. I’ve broken about 4-5 aluminum couplers running open builds high torque motors and ball screws with 10mm shaft

    been searching for hours for a stainless option. Just can’t locate one. Anybody have a lead?

    So looking for a 6.5mm to 10mm.

    thanks
     
  2. Rob Taylor

    Rob Taylor Master
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    Are you using spider couplers? I've never had a problem with those and I'm running NEMA 34s.
     
  3. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    They shouldn't break, unless operated at rather large off angle, off axis or stretched. Show us then in-use application and we'd be happy to help you determine if there is any room for improvement

    Also, as we don't sell those particular dimensions ourselves, are you purchasing from a place known for reliable quality?
     
  4. Dave Dreher

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    52166821-2C01-47A1-8D95-2642D1315847.jpeg Not the spiders. See picture. Best guess is around 200 running hours. Unknown quality. Just what looked good on Amazon. It is a bit odd of a transition dimension. I’ll try the spiders.
    Where is a good place to buy quality couplers? I’m open builds for electronics. But still running my diy mechanical kit. 52166821-2C01-47A1-8D95-2642D1315847.jpeg
     
  5. Gary Caruso

    Gary Caruso OpenBuilds Volunteer
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    Looks like that motor bracket isn't stiff enough and there is a bit of offset to the motor shaft to screw. fix that and you wont break anymore.
    Put the coupler together with the motor, get the coupler snug with the motor bolts loose and if the motor isn't sitting flat against the bracket fix that.
    If the motor bolts are binding then enlarge the holes on the bracket until the motor can go where it needs to go.
    Also make sure you are not stretching the coupler.. the couplers with the rubber bumpers in between are stronger and more forgiving.

    cheers
    Gary
     
    Peter Van Der Walt likes this.
  6. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Ps: our motors are 6.35mm (1/4 inch) not 6.5mm. Not sure of that contributed to your breakage, as the motor shaft would be more offset than intended.

    I also see the step in the post-break coupler there that looks like the motor is offset off-axis.

    Improving the alignment will make any type of coupler last longer
     
  7. Dave Dreher

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    I mistyped 6.5. I am talking about 6.35

    i Can see the offset when I zoom in. Good catch. I have some spider style couplers coming. I’ll take a look at alignment when they go in. I’ll lubricate blocks to. Machine has sat 2-3 months.
    Thanks.
     
    Peter Van Der Walt likes this.

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