There should be a HUGE Warning before buy the KIT Version  

RE: There should be a HUGE Warning before buy the KIT Version

I've built MK3S+ clone just recently (see my "Printed parts" comment here), so I decided to print parts by myself (on Mini). I downloaded necessary STL files from Prusa and printed them.
The problem is not the print quality (at least not the only one). The thing is, hole dimensions for shafts are dimensioned too tight. That is, hole for shaft has the same diameter (8mm) as the shaft that is needed to be inserted. In filament print world, that just can't work, because filament shrinks at cooling down -I guess hammer is a must have in Prusa factory.
Because I was unable to insert shafts (same as you), I redesigned those parts by just slightly increasing holes and printed them again. Now it's just perfect. Btw. I had the same problem with hex nut that needs to be inserted in x-end-idler.

Actually I don't have some good advice... maybe you try with more force.. I hope you will succeed.

RE: There should be a HUGE Warning before buy the KIT Version

My Dad had a drill with the right diameter and he could clean the hole to get them in.
Sorry but hat stuff should be fixed since... the Printer got sold as Kit. The same for the Lubricant I needed Isopropanol to clean everything after the installing. My hole Desk was covered. Who have that at Home?!

Sorry to say but the Printer Kit is not for everyone! It for People who have a "base Set" of Machines, Tool and a Work Bench at Home and a lot of Time and People who could support them.

RE: There should be a HUGE Warning before buy the KIT Version

Posted by: @prusaprinters-profile

...Sorry to say but the Printer Kit is not for everyone! It for People who have a "base Set" of Machines, Tool and a Work Bench at Home and a lot of Time and People who could support them.

Agree completely. Many are underestimating the needed amount of skill and tools that might be necessary to properly assembly the MK3S kit version. Ok, after you made it, you saved 200 bucks.. but many also say, they should have bought assembled version instead.

And.. uhm.. you didn't know you should be careful with lube? 😳 -sorry, I just couldn't resist 😊 .

Wish you successful assembly.

RE: There should be a HUGE Warning before buy the KIT Version

I am having the same issue with assembling the MMU2S. I thought it would be fun, but it is going very slowly. I am not interested in getting a drill press. I did get a vise which helps and I am filing things by hand. Customer service has been helpful, but I was surprised at how much filing I need to do.  I am so glad I got my MK3S+ factory assembled. 

RE: There should be a HUGE Warning before buy the KIT Version

It sounds like the complexity & time investment of the kit was underestimated. That's a shame. I just finished building my Mini+ kit over a week of evenings & total of about 10 hours or so. I found it quite enjoyable and a good learning experience. One thing I found very helpful was reading ahead in the instructions, and particularly looking at the comments on every step. Where there's many comments that was a flag to me that the step was going to be particularly difficult, so I made sure to check carefully for issues encountered and solutions found. The linked step in the OP currently has 64 comments--it's clearly a tough one and there's several solutions mentioned.

It's not for the first time builder

First time builders should be wary of taking on building a high precision computer controlled machine.  Building machines takes skill, patience and sometimes tools that are beyond what could be shipped in a kit.  That said however, I've built two of them now and went into it expecting there to be some learning curve - and there sure was.  IMO, the Prusa kits are capable of really high quality - but not easy to achieve for the first time builder.  Tolerances are tolerances - and if those rods were easy to slip into those holes, the quality would be impossible.  All of the axis need to be perpendiular, tightened in a particular order, and with great care.  Same as if I were to assemble a lathe in my shop - it would come in 20 crates, and I'd probably need a milling machine to do the fine fit.  The prusa kit is all included though - sounds like your parts may have warped while sitting for so-long.  

RE: There should be a HUGE Warning before buy the KIT Version

I'm really surprised to hear all of these issues.  I got my MK3S+ this past summer and had no issues at all with assembly.  In fact I thought the instructions, photos, comments, etc were very good.  I haven't built a printer before, nor have I built anything quite this small and precise.  But I needed no extra tools nor did I need to modify anything.  So quite surprising hear the issues.  If you've not communicated to PRUSA directly, I'd certainly do that since the Forum and Blog responses are not necessarily from PRUSA reps.

RE: There should be a HUGE Warning before buy the KIT Version

I didn't have any problems pushing the rods into the parts. I did lube the rods a bit with the grease and that seemed to help. As for the rest of the kit, it took me the span of 2 days and had no major issues. It was one of the smoothest and enjoyable builds I have ever experienced.

RE: There should be a HUGE Warning before buy the KIT Version

I found some of the rods a bit stiff to go in but nothing that a good twist, gentle thump and some choice words couldn't fix.  I had no mechanical knowledge other than assembling the MK1 and then MK2 upgrade back in the day.  Oh and I didn't use any tools other than what was supplied.  It took me about 4 days to assemble in total.  If you couldn't get the rods in at all you should have contact Prusa via the chat feature straight away.

RE: There should be a HUGE Warning before buy the KIT Version

My big burning question is did you contact Prusa support about this?

The rods and bearings are intended to fit closely with an absolute minimum of play.  Both the rods and bearings are stock items and it's possible that the combined tolerance of the rods and bearings is such that they will not fit as intended.

It's been almost two years since I assembled mine, but I do remember that the fit of the bearings is snug and tricky, but mine did not require any hammer-tap or 'chasing out' of the holes.

One thing I found most helpful was to read all of the assembly comments before assembling (I did it before ordering the kit) as steps that gave others trouble are fairly well documented in the comments.

As to assembling the MMU2S, I did this as well and I found that the assembly and testing was MUCH more tricky and challenging and did require some reading between the lines to get it working reliably.  Also the assembly instructions did not appear to have been written with the same level of TLC as the instructions for the MK3S.  I cleaned up the plastic parts carefully, but I did not have to do any filing or drilling to get everything to fit and to work.

RE: There should be a HUGE Warning before buy the KIT Version

How tite should I screw the screws in?
https://help.prusa3d.com/en/guide/6-lcd-assembly_172423#172687
I cracked enough parts before so i dont want to crack the display to...

RE:

I would say 'finger tight and then some', but in the case of the front panel, you will really have to try to break it.

Just (LOL) don't use an impact tool or something.  😉  With the nuts in place and the threads being metal to metal, there's little danger of stripping anything or crushing anything on that particular piece.

RE: There should be a HUGE Warning before buy the KIT Version

I think especially for Prusa printers you have everything available before you buy it. You can watch a lot of building videos. The building instruction is available online without any restrictions. So everybody should be able to decide for yourself if this is something easy or hard to build. 

It should be pretty obvious that it's not a Lego with 5+ tag 🙂

RE: There should be a HUGE Warning before buy the KIT Version

Hard to describe to someone not necessarily familiar with mechanical stuff.  My finger tight is more than I'd use on plastic parts.  Assuming you're not gripping the screwdriver with your fist, you have to feel for resistance.  If you're threading into a nut that's easier than treading into plastic. But as resistance goes up you can "feel" the resistance increasing until it becomes "finger tight".  Other than the frame and stepper motor screws there really isn't a reason to crank down on any of the other bits.  

RE: There should be a HUGE Warning before buy the KIT Version

omg... The screwholes dont fit.

https://help.prusa3d.com/en/guide/7-heatbed-psu-assembly_172872#173491

What is wrong now? Thanks

RE: There should be a HUGE Warning before buy the KIT Version

What does not fit?

The holes in the heatbed through which the screws go, or the holes in the 'squished frog' into which the screws go?

RE:

There must be some variability in the parts... my friend built one of these a couple months ago. He's totally unused to precision machinery, has no tools beyond the most utterly basic (certainly nothing powered), and he drank wine continuously throughout each build session. It took him a lot longer than expected, but his printer turned out great.

RE: There should be a HUGE Warning before buy the KIT Version

There are tolerances in everything that's machined, and sometimes cumulative tolerances will bite you!

RE: There should be a HUGE Warning before buy the KIT Version

I think if you will comply about each and every step, you will never make it. Take some deep breath, be precise and think about.

Thousands of MK2/3 printers (tens, or even hundreds of thousand) have been built, many help can be found on forums. Finally, it is only about your dexterity. Questions like "How tite should I screw the srews" are really pointless. It might help you to vent your anger, but sure will not help you to finish it and also will not bring other people to really help you. Be fair, that step is pretty clear and simple. The srew is not holding a house, it just fix the LCD to the cover not to move.

Yes, sometimes shit happens, you can break something. And after that, you will find out, that many people will help you to deal with. With and advice or spare part.