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MMU kit: Can't remove old pulley.  

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DDubyah
(@ddubyah)
Active Member
MMU kit: Can't remove old pulley.

Hi there. I've got a factory assembled mk2, and i'm trying to fit the multi material upgrade kit. I'm on the step "3.2 The Extruder Assembly: removing the old pully". But the socket of the grub screw seems to be stripped, so i can't unscrew it to remove the pulley! I've tried several 1.5mm allen keys but they're all turning freely in the grub screw socket.

Aaarg! How do i get past this? Every time i sit down to try to fit this kit i'm hitting a really frustrating problem. Any help would be greatly appreciated.

Opublikowany : 27/10/2017 5:01 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MMU kit: Can't remove old pulley.

A factory assembled unit may have Loctite on the screw.

You may need to cut a slot in the top so you can undo with a screwdriver. You could also apply a little heat, but be careful as you could damage the motor.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Opublikowany : 27/10/2017 5:21 pm
DDubyah
(@ddubyah)
Active Member
Topic starter answered:
Re: MMU kit: Can't remove old pulley.

Hmm, good thinking - I’ll see if I’m brave enough to cut a slot in it with my dremmel.

Opublikowany : 27/10/2017 6:03 pm
DDubyah
(@ddubyah)
Active Member
Topic starter answered:
Re: MMU kit: Can't remove old pulley.


You could also apply a little heat, but be careful as you could damage the motor.

Peter

Using a soldering iron should be ok to apply a little heat to it, right? Figure it’s more local than a heat gun. What you think?

Opublikowany : 27/10/2017 9:44 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MMU kit: Can't remove old pulley.



You could also apply a little heat, but be careful as you could damage the motor.

Peter

Using a soldering iron should be ok to apply a little heat to it, right? Figure it’s more local than a heat gun. What you think?

There's a big lump of brass there; I don't think a soldering iron will be effective, but it's certainly worth a try.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Opublikowany : 27/10/2017 10:47 pm
karel.k
(@karel-k)
Active Member
Re: MMU kit: Can't remove old pulley.

Had the same problem. I ended up with drilling out the grub screw with 2mm dril.

Opublikowany : 30/10/2017 9:06 am
DDubyah
(@ddubyah)
Active Member
Topic starter answered:
Re: MMU kit: Can't remove old pulley.


Had the same problem. I ended up with drilling out the grub screw with 2mm dril.


That’s plan B I guess. I’ve just bought some “screw extractor” bits, so going to give that a go. Did you manage to salvage the pulley?

Opublikowany : 31/10/2017 10:53 pm
DDubyah
(@ddubyah)
Active Member
Topic starter answered:
Re: MMU kit: Can't remove old pulley.


QA factory assembled unit may have Loctite on the screw.

You may need to cut a slot in the top so you can undo with a screwdriver. You could also apply a little heat, but be careful as you could damage the motor.

Peter

Worked a treat, thanks. Cut a slot in the top with a dremel, used a screw driver to get the grub screw out. Had to use a heat gun to apply a little heat to the pulley to get it off the shaft. No Loctite, thankfully. I’m back in business. Yay!

https://imgur.com/a/VKouE

Opublikowany : 02/11/2017 12:11 am
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