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3/8" to 8mm flexible coupling

Discussion in 'General Talk' started by K. Solberg, Sep 12, 2017.

  1. K. Solberg

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    Hi.
    I have ordered my first openbuilds kit, the minimill. I already have nema23 stepper motos with 3/8" 0.375 9.525mm shaft. I've tried to search for flexible couplings to use on this project but are only able to find some on stainless steel costing 250 a piece. Anyone know some affordable quality couplings, or will have to customize some myself?
    Regards
     
  2. SugarJ

    SugarJ Journeyman
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    Buy the closest size couplings that are a bit small and drill them out on a drill press. I've done it before with no issues. Take the grub screws out first or back them off enough that you won't hit them with your drill bit.
     
  3. K. Solberg

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    Yeah, that's what I thought I would have to do. Thanks..
     
  4. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Can't say for certain but the ones that come with the mini-mill kit just might work. Unfortunately though, I don't have any extras that I can to drill out to verify and visually they are too close to call. But as they're already coming with the kit it's probably worth checking out.

    Did find these but they're still a bit on the expensive side.
     
  5. K. Solberg

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    Ok. I'll see if I can drill those that come with the minimill first. I already have a 3/8 drill bit. If not I'll check out the two other options. I didn't see those on ebay. How are those couplings with red lining? They look soft..
     
  6. Giarc

    Giarc Master
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    I had a friend turn down my lead screws to 8 mm from 3/8 and my 1/2 inch (1500 mm) down to 12 mm. I tried drilling one out on the drill press and destroyed it. But I went right to a 3/8 bit. I think I would have been better off starting smaller and working up to 3/8.
     
  7. Gary Caruso

    Gary Caruso Veteran
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  8. K. Solberg

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    Giarc: it's the shaft of the motor that is 3/8.
    Gary: that coupling has been mentioned earlier in the thread. We'll see if I manage to convert the ones on the kit to 3/8 first.

    I've also ordered one from AliExpress in stainless 8mm to 3/8 to check out. A bit more expensive than aluminum at about 20 USD.

    ball screw coupler stainless steel coupling D 25mm L 31mm flexible clamping coupling stepper motor coupler for linear shaft 1pcs-in Shaft Couplings from Home Improvement on Aliexpress.com | Alibaba Group
     
  9. Gary Caruso

    Gary Caruso Veteran
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    that stainless one is nice, but costs as much as a stepper!
     
  10. K. Solberg

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    Nothing machined from stainless steel is cheap. I ordered only one, to check out the quality first.
     

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