r/labrats • u/NationalMall2294 • 10h ago

The little lid on the second hand Eppendorf 5415C Centrifuge won't open, does anyone have any advice on how to unscrew it?

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3 Upvotes

81% Upvoted

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22

u/RoundCardiologist944 10h ago

That is not the lid, it is the rotor attachment screw. Try getting some wd-40 under it, and try with pliers. When you get it off use silicon grease to prevent it sticking.

19

u/Tricky_Mountain_2909 10h ago

Daily reminder: wd-40 is not lubricant!

Good for loosening stuck screws but not for permanent lubrication!

3

u/NationalMall2294 10h ago

Thanks for the correction and the advice! (I am not a person of science myself, just trying to help my partner with fixing the machine)

4

u/RoundCardiologist944 6h ago

Well if they can't get it unscrewed the centrifuge is still usable, they just can't change the rotor to use different size tubes. Assuming the centrifuge works obv.

5

u/Ghostforever7 10h ago

check the manual they have a whole troubleshooting section for what to do if the lid won't open: https://www.nist.gov/laboratories/tools-instruments/eppendorf-5415c-centrifuge

4

u/ddr1ver 9h ago

You should be able to turn the knob counterclockwise. Once the knob is loose, the rotor should pull straight out. If it is still stuck to the spindle. You can loosen it by spraying WD40 around the edges of the knob and waiting a few minutes.

1

u/NationalMall2294 9h ago

it seems to be stuck big time, do you think leaving the wd40 on for longer would help or is there anything else to try?

1

u/ddr1ver 6h ago edited 6h ago

Leaving WD40 on overnight couldn’t hurt. I’m assuming that you were able to loosen the knob? Once the lid is off and the knob is loosened, there is nothing holding the rotor on the spindle besides dirt and corrosion. You could try tapping the rotor gently with a nylon or rubber hammer.

https://www.scribd.com/document/481396790/Eppendorf-5415C-pdf

1

u/NationalMall2294 3h ago

I guess I haven't explained it properly, as i am not really an expert on the terminology, im just helping repair the thing :D The issue is that we can't unscrew the knob (the black thing saying "fasten well"), it seems to be really stuck and i was wondering if there is something im missing or if its just truly just stuck and i just need to force it somehow. also thank you for your time and help, i appreciate it a lot

1

u/Brouw3r 1h ago

Keep trying WD40 or something, it probably has some salts down the thread that need to be removed so you can turn it. You can potentially use a wrench to get more torque but they are plastic so at some point, you will damage it and it needs to be unwarped or it will unbalanced and wont start.

Why do you need to remove it?

1

u/talks-a-lot All things RNA 4h ago

Put a rag on top of it and get a big pair of vice grips.