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Screw broke off in frame in Z-Axis assembly  

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thomas.b9
(@thomas-b9)
Active Member
Screw broke off in frame in Z-Axis assembly

In Step 4, Part 3 of the instructions, it says to assemble the frame and 3D printed parts together for the Z-Axis with M3x10 screws. However, I could not get any of them to even go into the frame, let alone thread in. I finally got one screw to go in... but it broke off before it even touched the 3D printed part.

The screw holes don't even seem threaded. In fact, they're probably a size too small for this. Everyone says to use lubricant for this step (which I tried, makes absolutely no difference), and don't go at an angle (which I actually didn't, I went as far as using the 3d printed piece to keep it as straight as possible). And it still broke off, and any of the other 6 screws won't even go in.

I've tried everything for the last two hours and I might throw in the towel today... 🙁

What can I do? And what's wrong here?

Publié : 14/01/2017 6:07 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Screw broke off in frame in Z-Axis assembly

Contact support - use the "Live Chat" and give them a link to this thread.

It does appear that the holes have not been threaded so you should be able to get a replacement sent out.

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…

Publié : 14/01/2017 6:26 pm
Systronix Inc
(@systronix-inc)
New Member
Re: Screw broke off in frame in Z-Axis assembly

You are not alone. This seems to be happening with several recent shipments. I had the same finding of no apparent threads in the frame and foolishly I just followed the instructions on the Z-motor mounts, barely getting the screws in. Finally I realized something must be wrong, and purchased a 3mm tap and tapped the rest of the holes.

It should be possible to use a small ez-out to back out that sheared screw, or ask Prusa to send a new frame and new screws.

Even good companies make mistakes and from other threads here, Prusa will make this right.

Publié : 14/01/2017 10:04 pm
thomas.b9
(@thomas-b9)
Active Member
Topic starter answered:
Re: Screw broke off in frame in Z-Axis assembly

You are not alone. This seems to be happening with several recent shipments. I had the same finding of no apparent threads in the frame and foolishly I just followed the instructions on the Z-motor mounts, barely getting the screws in. Finally I realized something must be wrong, and purchased a 3mm tap and tapped the rest of the holes.

It should be possible to use a small ez-out to back out that sheared screw, or ask Prusa to send a new frame and new screws.

Even good companies make mistakes and from other threads here, Prusa will make this right.
Just went to the hardware store and picked up an M3 tap. I'll report back if I actually get the other threads tapped, but the broken screw isn't budging with any removal efforts. I'll have to drill it out and damage the frame... 🙁

Publié : 14/01/2017 11:13 pm
thomas.b9
(@thomas-b9)
Active Member
Topic starter answered:
Re: Screw broke off in frame in Z-Axis assembly

UPDATE: The frame works beautifully now!! All I had to do was take an M3 (3mm) tap to 20 of the screw holes (not the 4mm screw holes, or the bottom 4 meant for zip-tie management). Guess we'll see how it holds up!

Publié : 15/01/2017 12:44 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Screw broke off in frame in Z-Axis assembly

Thanks Thomas,

I think I will also do that when I get my new printer... and when I upgrade my old printer I will clean out any holes that become visible...

when I upgraded my old printer from Mk1 to Mk2, I had some difficulty with the threads in the big frame,
particularly the screws for the electronics,

I am considering fitting chains so the electronics case will have to come off anyway.

regards Joan

p.s. I already have a 3mm tap...

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

Publié : 15/01/2017 2:11 am
plc268
(@plc268)
Active Member
Re: Screw broke off in frame in Z-Axis assembly

I have the same problem. Holes had no thread, and the screws were slowly cutting their own thread. I made sure to back the screw out and clean the hole every so often, but when I got near the end, the head snapped off. 👿

It took quite a bit of effort drilling the screw out. It being stainless steel, it's quite difficult to drill if you don't have a drill press sitting around. Managed to break several HSS drill bits before I finally found a cobalt bit small enough. It's not pretty looking now, but I'll have to go find and pick up a tap set to tap these holes. If all else fails, I guess I'll have to contact support.

Publié : 15/01/2017 7:21 am
thomas.b9
(@thomas-b9)
Active Member
Topic starter answered:
Re: Screw broke off in frame in Z-Axis assembly

Managed to break several HSS drill bits before I finally found a cobalt bit small enough.
I literally just took a punch and a hammer to the screw once I broke 3 drill bits... 😀

Publié : 15/01/2017 10:42 pm
plc268
(@plc268)
Active Member
Re: Screw broke off in frame in Z-Axis assembly

Managed to break several HSS drill bits before I finally found a cobalt bit small enough.
I literally just took a punch and a hammer to the screw once I broke 3 drill bits... 😀

I wish I thought of that at the time. I probably would've been left with a cleaner looking hole too, as the hole I drilled wasn't perfect, and now the right side z motor mount doesn't screw in perfectly. Whether or not this will affect the functionality... we'll see.

But yea, I went and bought a tap and die set and cutting oil, and easily tapped all the remaining holes. Screws went in easily after that.

Publié : 16/01/2017 7:56 am
jonathan.r10
(@jonathan-r10)
New Member
Re: Screw broke off in frame in Z-Axis assembly


Managed to break several HSS drill bits before I finally found a cobalt bit small enough.
I literally just took a punch and a hammer to the screw once I broke 3 drill bits... 😀

bringing this thread back to life... I recently bought a MK2S printer and got nearly to the end without a problem. When trying to get some of the last M3 screws into the aluminum frame one of them broke off into the frame (see photo).

Did anyone in this thread manage to get their broken screws out? I feel like I've tried everything... drilling out the screw wouldn't work because it's stainless steel, couldn't get a screw extractor in there for the same reason..

Publié : 07/01/2018 8:41 pm
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