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C-beam endplates

Discussion in 'OpenBuilds Bug Report' started by jluther, Aug 13, 2015.

  1. jluther

    jluther New
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    I am assembling my C-Beam Actuator and it seems like the lead screw and NEMA 23 mounting location are off. When I use the anti-backlash nut, the 8mm lead screw needs to flex in order to tighten down the nut. Initially I was thinking I'd just shim the nut, but when I mount the NEMA 23, it appears to be where the offset is. It appears that it's about 1/16" off toward the extrusion on both plates.

    I can throw it up on a Keyence inspection system after work tomorrow, to determine how bad it is. If it'll help.
     
  2. Michael Shore

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    I added 2 extra 3mm spacers on my backlash nut to stop the acme rod from bending, the NEMA 23's all look straight and fine when running.
     
    Mark Carew likes this.
  3. Mark Carew

    Mark Carew OpenBuilds Team
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  4. Michael Shore

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    I ended up adding an extra 3mm spacer to each M5 bolt so a total of 6mm on each bolt.

    This has allowed me to really snug the backlash nut block down keeping the acme rod straight.
     
    #4 Michael Shore, Nov 11, 2015
    Last edited: Nov 11, 2015
  5. dddman

    dddman Journeyman
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    Did you try to loosen your motor and your plates first to try to align everything right first?

    When you remove only the front plate, does the rod stays centered? (when the carriage is on the back)
     
  6. Michael Shore

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    with both spacers on each bolt yes, with only one as in the build video and the available models, no the rod deflects upwards out of the C-Beam. all 3 of my rods are like this.

    I am quite happy to take it all apart and make some measurements if needed, but if the end plates are wrong then I have 6 all the same!.

    Michael
     
  7. dddman

    dddman Journeyman
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    can you send some pictures? I'm curious :)
     
  8. Michael Shore

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    Dany, 3 images

    1 with just the supplied 3 mm spacers clearly showing the rod lifting out of the C-Beam
    Nut block with 2 x 3 mm spacers
    and end view of the acme rod when 2 x 3 mm spacers are on the block, the rod is slightly lower than I would like, but I didn't have any smaller spacers, but it is much better than with just the supplied 3 mm washers

    I have measured my end blocks and they are spot on, my nut blocks have a 2 mm recess for the 3 mm spacer.

    Hope that all helps

     
  9. Mark Carew

    Mark Carew OpenBuilds Team
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    Looks to me that it may be bent lead screws. I build these actuators almost on a daily basis without any issues like this so I am curious as to what could be causing this. I will talk to the Part Store Team about sending out some new leads if we find this is the cause.
    I will discuss this further with you in the PM you sent me Michael and we will get this fixed up for you, thank you for the feedback.
     
  10. Michael Shore

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    After conversations with Mark and the exchange of images of my build, it turns out I have been supplied ( a UK Supplier ) with the wrong spacers, the incorrect spacers have a diameter of 8 mm and sit inside the recess in the anti back lash nut, the 3 mm spacers should sit on top of the nut, this is why I had to add additional spacers to bring the nut to the correct level and have a straight lead screw.

    Many thanks to Mark for all his help.
     
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  11. Flash22

    Flash22 Well-Known
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    all you needed was the larger dia spacers so they don't drop into the recesses of the nut block, my posts about this have been moderated/deleted prob why you didn't find anything on the forum

    I ended up, turning up 5.4mm long spacers to get over my issues
     

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