Solutions for (X-axis) grub-screws vibrating loose over time
 
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Solutions for (X-axis) grub-screws vibrating loose over time  

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mrstoned
(@mrstoned)
Reputable Member
Solutions for (X-axis) grub-screws vibrating loose over time

I wonder if anyone have a good long-term solution for grubscrews vibrating loose over time.

In my case, the x-axis pulley came loose and i have to re-tighten it.

My printer only have about 20ish hour print time so far. The y-axis is still tight.

 

I realize i may not have tighten them fully at buildtime, but at the same time they are tiny and somewhat fragile.

Prusa Mini+ kit. BondTech extruder. FW 5.1.2
Prusa MK3S+ kit. Stock. FW 3.11.0
Prusa MK3S+, used. Stock. FW 3.13.3

Posted : 18/05/2021 9:11 pm
Crawlerin
(@crawlerin)
Prominent Member
RE: Solutions for (X-axis) grub-screws vibrating loose over time

Does it "shake out" from vibrations or just does not cut to plastic anymore? I can only think of some solution with nyloc nut, or M3 head insert and loctite. Haven't tried either of those. 

Belts usually stretch over time, give them ~24 hours of printing and then tighten again. This is recommended for new printers too, I think I saw it in MK3S manual (don't quote me on that).

Posted : 18/05/2021 9:31 pm
Technical Ted
(@technical-ted)
Trusted Member
RE: Solutions for (X-axis) grub-screws vibrating loose over time

Don't know where you are located, but in the states I use blue Loctite for things like this. Blue is used when you want to be able to remove the screw for maintenance or whatever. Other grades are too strong. 

Ted

 

Posted : 18/05/2021 10:15 pm
cwbullet
(@cwbullet)
Member
RE: Solutions for (X-axis) grub-screws vibrating loose over time

@technical-ted

That would work.  Make sure you have a good Allen key or you might strip them.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 19/05/2021 1:04 am
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(@)
Illustrious Member
RE: Solutions for (X-axis) grub-screws vibrating loose over time

If two set screws in a gear - use the flat first method, and the screws self lock in place. 

  • Loosen both screws so the gear can spin freely on the shaft.
  • Align and tighten the first set screw with the shaft flat, wiggling to ensure the tip of the set screw sits flat on the shaft. Torque to spec.
  • Tighten the second set screw on the shaft round. Torque to spec.
  • Do NOT go back and try tightening the screw on the flat - you will strip it.
  • To remove the gear, loosen the set screw on the round first, or you will risk stripping the screw on the flat.
Posted : 19/05/2021 8:08 am
mrstoned
(@mrstoned)
Reputable Member
Topic starter answered:
RE: Solutions for (X-axis) grub-screws vibrating loose over time

Thanks.

I'm in sweden and will check on the loctite.

It's the pulley on the motorshaft i had to tighten but i had to "feel" where the flat area as it's not visible inside with pulley on the shaft. The axel on the back of the motor is round and i didn't think of marking it on the backside as well :/

For abit larger sizes, M3-4 and up i somethimes use a thin strip of the plummers teflon tape and just insert it in the threads and then tighten. It hasn't failed me yet. It becomes pretty much the same thing as having a nyloc nut but also works for stationary threads.

Gotta get myself some better tools then what came with the mini.

Prusa Mini+ kit. BondTech extruder. FW 5.1.2
Prusa MK3S+ kit. Stock. FW 3.11.0
Prusa MK3S+, used. Stock. FW 3.13.3

Posted : 19/05/2021 8:53 am
cwbullet
(@cwbullet)
Member
RE: Solutions for (X-axis) grub-screws vibrating loose over time

@mrstoned

I think the colors are the same.  I used to use the blue stuff in Germany and I am pretty sure I did not have it shipped by McMaster Carr.

--------------------
Chuck H
3D Printer Review Blog

Posted : 19/05/2021 11:04 am
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