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Replacing bushing covers on x/y axis rods

Discussion in 'Troubleshooting' started by adikted2astro, Nov 19, 2019.

  1. adikted2astro

    adikted2astro Active Member

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    So I was putting my printer back together today and after I mounted the extruder head back in the gantry, I realized one of the bushing covers/sleeves was bulging out and the reason was because it broke :(. I have replacement covers and as a matter of fact, I have some graphite plugged bushings that I never installed. My question is two-fold. First, is it worth the effort to replace the bronze bushings entirely, since I already have the printer apart? Second, I don't want to misalign this broken one, so is there a good way of taking out that belt without "losing my spot", so to speak? I'm worried that taking apart those gantry rods to replace the bushings is going to be a lot of effort because I will have to realign everything, but I've never done it so............................?

    The printer is completely apart because I found a curious problem on the lead screw that could quite possibly have been my problem all along with homing, UBL, everything. The lead screw can actually jump up and down when the motor is mounted and I have seen it do so. So I'm replacing it completely.

    EDIT: The only caveat is the graphite plugged bushings I have are 6mm shorter than the original bushings. However, I don't think that would be an issue.
     
    #1 adikted2astro, Nov 19, 2019
    Last edited: Nov 19, 2019
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    You can replace the bushings safely and the frame will basically realign the gantry for you, so it really isn't as much work as you thing it will be.
     
  3. adikted2astro

    adikted2astro Active Member

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    Yes, after thinking about it last night and this morning, I realized it wouldn't be difficult, so I pulled the trigger and replaced the bushings with plugged graphite bushings. I will put it all back together tomorrow. I was concerned that the bushings wouldn't be long enough; 30mm as opposed to 36mm. However, they will work perfectly. They installed with no problems and they are secure in the housings; they don't move much at all. I did have to throw away all of the plastic housings or covers, or whatever they are called, and use new ones. Those things are not made to come apart (without breaking) in any way and believe me, I was trying hard not to break them even though I had new ones.
     
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  4. adikted2astro

    adikted2astro Active Member

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    Putting that cage back together wasn't easy, but it wasn't hard either. It just took a while to get everything aligned properly. I had to restart from scratch a couple times because I kept forgetting to put the bushings and belts on properly.
     
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  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    A learning experience ;)
    Well done, sir.
     
  6. adikted2astro

    adikted2astro Active Member

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    Thanks. I'm looking forward to not having to oil those 8mm rods. They used to get really nasty before. You should've seen what they looked like inside when I took the original bushings out. I'd love to do the same for the 6mm X/Y axis rods too. I have the plugged graphite bushings to do it, but that's going to take some creative printed parts to house the replacements. Their outer diameter is no where near the same as those linear bearings.

    I'm going to find out how much some custom bearings would be. Specifically 6mm ID, 12mm OD, 35mm long. I'm sure it will be expensive, but it might be worth it. The bearings I have now are 6 x 10 x 20, so they actually won't work in any way because I won't be able to double them up. Also, they are made for rotational and linear motion, so I would actually need something different.
     
    #6 adikted2astro, Nov 21, 2019
    Last edited: Nov 21, 2019
  7. tkoco

    tkoco Administrator
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    I agree with @mark tomlinson .
     
  8. adikted2astro

    adikted2astro Active Member

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    The extruder head moves better and smoother than it ever has. I'm very surprised at the difference these bushings made.
     
  9. tkoco

    tkoco Administrator
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    Quick question: "Where did you get the graphite bushings?"
     
  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    The are not completely graphite, they are likely oil impregnated bronze bushings with graphite plugs. You can get them all over AliExpress, Banggood, eBay, maybe even Amazon (for a slightly higher price).
    [​IMG]
     
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  11. adikted2astro

    adikted2astro Active Member

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    I honestly can't remember. I think Aliexpress, but I can't be certain. I bought them almost 2 years ago and never used them until now. I can honestly say it was well worth it. My printer is moving so smoothly now. It's astonishing really. The replacement z-axis motor and lead screw I put in are magnificent and better than I could've hoped for. However, for some odd reason, I had to flip the z-axis motion in my config.h file because after I installed it, it would go down if I told it to go up and vice versa. Weird because I've had to replace it before and that didn't happen. But, whatever, it is worth it.

    I'll see if I can find where I got the bushings and post a link.
     
  12. adikted2astro

    adikted2astro Active Member

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    Here is where I got them: https://www.robotdigg.com/product/175/Selfgraphite-ID8*OD12-Linear-Bearing. I got the 30mm ones (SGB081230)

    They are not as long as the original bushings, but trust me, it doesn't matter. Once you put the bushing in the bushing block and close it, the bushing stays where it is and does not move at all. I have put in a quote request at a couple of places for some graphite plugged bearings for the X/Y axis rods. However, they will probably make me buy a large amount of them, or minimum $$$ order. So my question is, are any of you interested in a set when/if I can get them?
     
  13. adikted2astro

    adikted2astro Active Member

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    Ok I'm about to start seriously looking into a mechanical probe. My IR sensor sucks no matter what the bed material is. I bought a new one with the other components and installed it just now. I will see how well it works in the morning. But the last 2 sensors I've had just did not work well at all and I'm not hopeful of this one.

    Here is what happened, I performed a G29 P1 (for UBL) and some of the points were up to 0.8 mm off of the z-offset. I've never had them that big. I do have a new bed on there but even then, that's too much. So I decided to manually probe the mesh points by first dropping the bed to the z-offset, moving to the mesh X/Y position, then slowly bringing the bed up in 1mm and 0.1mm increments. The points that were supposed to be off by 0.8mm were only off by MAYBE 0.05mm; no more. I'll do the same thing tomorrow and see if the new sensor is any better. I think it might actually be faster and a lot less frustrating to do all of the mesh points manually like that, instead of printing a mesh, measuring each point, making corrections, then repeat.
     
  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Maybe something like a BL Touch (not saying that one is the way to go, but something similar). Would be easy enough to wire in I imagine.
     
  15. adikted2astro

    adikted2astro Active Member

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    Yeah, I've looked into those. I just have to figure out how to mount it properly before I can get one.
     
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  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    For all of hte fancy new IR sensors and touch/end-stop sensors they went with in the R2 and C2, they are still just open/close switches as far as the control board is concerned.
     
  17. adikted2astro

    adikted2astro Active Member

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    I just got the quote back for the custom bearings, 6mm ID x 12mm OD x 35mm long. They want $75.25 EACH. Haha, there's no way in hell I'm spending that kind of money for those. That's ridiculous.
     
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  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  19. albert3d

    albert3d Member

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    What about these?
    https://www.ebay.com/ulk/itm/153552765087
     
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  20. adikted2astro

    adikted2astro Active Member

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