Spec for MMU2 springs? - Hardware, firmware and software help

RE: Spec for MMU2 springs?

karl-herbert — Tue, 28 Apr 2026 22:06:07 +0000

Take a look here:

https://www.federnshop.com/de/produkte/druckfedern.html

wbr,

Karl

RE: Spec for MMU2 springs?

arbornoctis — Wed, 04 Feb 2026 17:29:29 +0000

Hallo! could you please share the link to the springs?

best regards from Germany as well :-)

RE: Spec for MMU2 springs?

karl-herbert — Mon, 04 Jul 2022 18:48:49 +0000

I use springs specifications like this: (not Prusa original):

innerdia.: 3.3mm

outerdia.: 4.9mm

spring steel 0.8mm

length: 15mm

allen screw length: 30-35mm

I unfortunately only know German sources or Prusa, but maybe you can find a spring store in your area.

wbr,

Karl

RE: Spec for MMU2 springs?

jsw — Mon, 04 Jul 2022 13:38:05 +0000

On a related note, I would strongly recommend printing and installing those thumbscrew extensions, available in the Prints section, and barely visible in the photo below.

These make opening the unit MUCH easier and reduces the chance of springs and bolts flying across the room.

You will need slightly longer bolts, available from about anywhere, to make these work.

RE: Spec for MMU2 springs?

Petr — Mon, 04 Jul 2022 12:46:38 +0000

Well, just try what you find at home or local store. It must only fit to the bolt and be long enough to be able to adjust the force. Tip: For hard filaments a spring from pen doesn´t work, you will need stronger one.

I had a different spring issue with printing softer filaments like flexible fil or PP and I had fixed it with softer spring from a pen.

RE: Spec for MMU2 springs?

walkitinkid — Wed, 15 Jun 2022 13:15:28 +0000

did you ever figure this out? I'm in the same boat.

Spec for MMU2 springs?

Laird Popkin — Sun, 24 Nov 2019 00:39:58 +0000

What are the specs for the springs? They tend (for me) to pop off the screws when opening the MMU2 to clear filament, and I've managed to lose one. I know I could get Prusa to send me one, but it seems overkill to ship a tiny spring internationally. Researching springs, they don't seem to come in standard sizes, but is there some way to locally source a spring for the MMU2?