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How to keep the screws and springs from falling out?  

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Anachronist
(@anachronist)
Estimable Member
How to keep the screws and springs from falling out?

When I remove the two spring-loaded screws to open up the MMU2S, often it opens wide enough that the two screws fall out with their springs. The screws are easy to find because they don't roll away, but the springs roll easily, and usually they seem to roll into some inaccessible place.

So far, I've managed to recover them - until today. I just lost a spring. I heard them drop. I've looked under the printer, behind my desk (and I found one of the springs there), all over the desk, and I cannot find the other one. Maybe it bounced up under the heat bed and stuck to a magnet, but I can't check that because I have a long print job running.

Fortunately I had a spare spring. But now I have no more spares. So I'm scared that I'll lose another one.

I'd like to have some way to keep the springs and screws inside their holes when I open up the MMU2S.

Best Answer by Anachronist:

Done! I needed to be able to see my tensioner screws from the front, so I remixed the screw capture plate. Here it is:

https://www.printables.com/model/172280-tension-screw-trap-for-mmu2s

Not counting the time to reverse-engineer it in OpenSCAD, this was a quick print, and really quick installation (3 minutes). I can still see exactly how tight my screws should be, and they don't fall out when I open the MMU2S.

I love it when there's an elegant solution to an annoying problem.

The only annoying problem remaining is that I know there's a spring still lost in my living room. Good thing I had a spare. And now I don't have to be worried about losing another one.

Posted : 10/04/2022 1:09 am
mkoistinen
(@mkoistinen)
RE: How to keep the screws and springs from falling out?

This is a real problem, I agree. It plagued me for quite awhile until I installed the LED Light Bar by user SethBon. The side-effect of this is that it restricts the ability of the MMU2S from opening enough for the screws/springs to fall out, but it still opens enough to correct filament paths as required. Not a real solution, but if you're if you'd like to add some lighting to your rig, this could kill 2 birds with one stone.

Since its installation over a year ago, I've neither had the problem of losing my screws springs, nor had to remove the light to fix any MMU2 filament loading issues and I use this printer daily.

Posted : 10/04/2022 6:05 pm
JoanTabb
(@joantabb)
Moderator
RE: How to keep the screws and springs from falling out?

if you take a sheet of  stiff polythene sheet, cut two tiny patches out, and pierce the centre. you can screw the screws through the polythene, and when you unscrew the screws the polythene should stop the screws and springs falling out!
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 10/04/2022 7:41 pm
ZombiPach
(@zombipach)
Eminent Member
RE:

https://whttps://www.printables.com/model/124431-idler-body-for-mmu2s-with-some-extra-featuresww.printables.com/model/124431-idler-body-for-mmu2s-with-some-extra-features

 

This is my favorite solution to the problem yet. Not only does it prevent screw escape, it makes working with the MMU MUCH nicer. 

 

This post was modified 8 months ago by ZombiPach
Posted : 10/04/2022 8:33 pm
Anachronist
(@anachronist)
Estimable Member
Topic starter answered:
RE: How to keep the screws and springs from falling out?

Wow, that's cool, but complex. You basically replace half of the MMU housing, and need to disassemble everything to install it.

That gives me another idea for a couple of removable spring-loaded clamps for each side of the MMU. The clamps would replace the screws and springs. The top of the clamp would fit into the existing screw hole, and the bottom would hook under the bottom edge of the housing. Simpler to print and no disassembly needed.

But I'll try JoanTabb's suggestion first. It's the simplest. I could also print a small washer that fits tightly in the hole and the screw fits tightly inside.

 

Posted : 10/04/2022 8:48 pm
JoanTabb
(@joantabb)
Moderator
RE: How to keep the screws and springs from falling out?

that should work! 
Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 12/04/2022 7:04 pm
JohnnyT
(@johnnyt)
Active Member
RE: How to keep the screws and springs from falling out?

Sometimes the simplest idea works the best.  Print in PETG & PC so they will last

https://www.printables.com/model/3151-mmu2s-tension-screw-retention-washer

 

Posted : 15/04/2022 1:30 am
Anachronist
(@anachronist)
Estimable Member
Topic starter answered:
RE: How to keep the screws and springs from falling out?
Posted by: @johnnyt

Sometimes the simplest idea works the best.  Print in PETG & PC so they will last

https://www.printables.com/model/3151-mmu2s-tension-screw-retention-washer

Cool! I don't have to design my own.

More complex solution to replace the control board cover with a new one that has screw-retaining extensions: https://www.printables.com/model/4591-mmu2-tension-screw-keeper

Posted : 15/04/2022 2:57 am
Anachronist
(@anachronist)
Estimable Member
Topic starter answered:
RE:

(damn time limit to edit a post)

...but I like this one:  https://www.printables.com/model/68165-screw-capture-plate-add-on-for-mmu2s - more robust than the washers and simpler than any other solution I've found.

Posted : 15/04/2022 3:09 am
JoanTabb
(@joantabb)
Moderator
RE: How to keep the screws and springs from falling out?

MMU2 now has a 'go faster' stripe option!   Lol... 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 15/04/2022 10:04 am
Anachronist
(@anachronist)
Estimable Member
Topic starter answered:
RE: How to keep the screws and springs from falling out?

Done! I needed to be able to see my tensioner screws from the front, so I remixed the screw capture plate. Here it is:

https://www.printables.com/model/172280-tension-screw-trap-for-mmu2s

Not counting the time to reverse-engineer it in OpenSCAD, this was a quick print, and really quick installation (3 minutes). I can still see exactly how tight my screws should be, and they don't fall out when I open the MMU2S.

I love it when there's an elegant solution to an annoying problem.

The only annoying problem remaining is that I know there's a spring still lost in my living room. Good thing I had a spare. And now I don't have to be worried about losing another one.

Posted : 16/04/2022 5:18 am
Anachronist
(@anachronist)
Estimable Member
Topic starter answered:
RE: How to keep the screws and springs from falling out?

Following up with a curious question: Why does that model not appear among my designs?

Here's the model: https://www.printables.com/model/172280-tension-screw-trap-for-mmu2s

...but it doesn't appear on my models page: https://www.printables.com/social/30575-anachronist/models

I wish there was a contact form for reporting problems on Printables.

Posted : 14/07/2022 6:01 am
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