# Specific 3D Printers, Scanners, & Hardware > MakerBot Forum >  MB 2X Circles aren't round

## hobbes

Got my 2X in the mail today. Set it up and did some test prints. I'm familiar with Makerbots from using a Rep 2 a few years ago and i also own a Folgertech Prusa I3 with a similar problem to what i'm experiencing with this 2X.

My circles are not round, they're football shaped. My old Rep2 did not have this issue at all. The Prusa does have it a little, but not nearly as pronounced as it is on my 2X.

I've looked on google and saw that this appears to be a common problem with the 2X? I can't seem to find a solution, though.  I've read that it may be a belt tension issue but, honestly, they feels pretty tight. I ordered some belt tensioners nonetheless, but in the mean time I wanted to check here if anyone knows of other possible causes, and solutions.

Thank you.

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## Roberto

Hi there
Belts have to be under right tension. Not too little, but also not too much tight.
Check all of them, including small one in the back.
Another thing you should check is angle and position of gentry. 
There should be almost perfect 90dgs between side and gentry itself.

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## MBSupport

Hey Hobbes. Please make sure your belts and pulleys are at the proper tension. Here are two videos that should help:

https://www.youtube.com/watch?v=p-YZ4Dod9ho

https://www.youtube.com/watch?v=3BMgn5Xin30

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## hobbes

Thank you for your quick responses.

Once i get home from work, i'll take a look at the pulleys/belts/gantry and report back.

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## hobbes

I apologize in the delay of updates. I was a bit busy last night, but i did squeeze in the adjustments. Unfortunately, I didn't succeed in getting any test prints done. I will be doing that after work today (4 hours from this post' timestamp).

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## hobbes

It's 12:30 and i'm a little tired. I took many pictures, as I put in 6 hours worth of small test prints. I'll upload just 3 for now to showcase a concerning issue i'm having.

*For all the prints, i'm using the standard 2X bed and nozzle temps (110 bed, 230nozzle). If there are better numbers for ABS on the 2X, please let me know.* I know that my prusa operates just fine at 100 bed and 200 nozzle.

The tensioning of the belts and gantry realignment seemed to have helped, but it wasn't obvious right away. The first prints didn't seem to have been affected much from it, but the more i use it, the better the rounds are getting.

You will notice in all 3 pictures i have arrows pointing to thin walls. In every case, the walls are just 2 layers thick with no infill, even though they were all set to *100% infill.* I have put samples from my prusa and from my old replicator 2 (which i don't own anymore) for comparison.





It's especially evident in this picture of my wheels. The wall is supposed to be completely filled out at the neck, where the axle gets inserted. Also, oddily enough, the print with 4 shells had more spaces between shells than the one with 2 shells.




It's not just limited to thin walled circles. On this chassis you can see that even straight walls are affected by this "no fill zone" problem.



Ideas?

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## curious aardvark

what slicer(s) are you using ?

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## hobbes

cura/repetier for the prusa, makerbot desktop for the rep 2X.
I was also using makerbot desktop with the old replicator 2, and as you can see from the wheel pic, it was giving me better results.

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## Roberto

Hi there
as you can see, infill doesn't affect spaces between shells.
To eliminate those I would advise 1 shell setting.

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## hobbes

> Hi there
> as you can see, infill doesn't affect spaces between shells.
> To eliminate those I would advise 1 shell setting.


That did it. Thank you!



I have other small concerns i'd like to ask about, but i will open a new thread with the appropriate title, so it will be easier to find for those seeking similar information.

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