Assembly Instructions change 3.21 -> 3.22  

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AlfaXL
(@alfaxl)
Active Member

Just getting my MK3S+ kit unpacked and checking parts + instructions. I see latest online version is 3.22, compared to my 3.21 printed instructions, and there is a small changelog section that seems to show only one difference. There is a picture of making a felt tip mark on the X axis bearing, but I can't see that in either version. It just seems to be confirmation of the correct orientation -is there more to it than that?

Any other updates from 3.21 that aren't in the latest changelog?

 

Posted : 18/04/2021 4:32 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member

The changelog is here https://help.prusa3d.com/en/guide/manual-changelog-mk3s-kit_213158   and yes, think there is only 1 change.

I would always recommended to use the online version, it is not just more up to date but has very handy comments, and much clearer photos that can be zoomed into.

I just use the printed version for reference after build if I wanted to check or tweak something.

Tank you very much!...
Posted : 18/04/2021 4:46 pm
AlfaXL
(@alfaxl)
Active Member

I like having the paper copy to make notes on, easier than annotating a PDF. I take your point about the comments though, I will probably scan through them and summarise in my Assembly Instructions before building.

But I still cannot figure out the point of the change - making a mark on the bearing. There is no context that I can see as to where it applies.

This post was modified 4 weeks ago by AlfaXL
Posted : 20/04/2021 9:38 am
Clarmrrsn
(@clarmrrsn)
Honorable Member

@alfaxl

Marking the bearings is done prior to the X axis bearing installation.

This is to ensure that when you install the bearings into their final positions 2 rows of ball races are evenly distributed over the top of the rods, if you did not do this, and had only 1 row on top (i.e 1 row at 12, 3 6 and 9 o clock) all the weight is on 1 row, and you could develop a wear line on the rods, and more noise/vibration from the bearings.

Prusa Knowledge Base | 3. X-axis assembly (prusa3d.com)

See Step 8

Tank you very much!...
Posted : 20/04/2021 6:58 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member

Meant to say the same process applies to the Y axis as well, although you do not actually need to mark the bearings to do this as can see them when fixing into the clips, it helps to put a mark anyway.

Also make sure that you pack your bearings well with grease, this really helps to keep then quieter.  Mark them after soaking in IPA and drying properly as its easier to see the ball races.

This method was recommended by Prusa Support when my bearings were a little noisy after installation. 

Soak the bearings in 99%IPA to remove the shipping oil, dry them thoroughly then mark the bearing positions as per the manual before packing with grease. Squirt a good amount (bearing about half full) superlube grease with PTFE (or prusa grease) inside the bearing, THEN put your finger over the other end of the bearing and insert the shaft perfectly straight and carefully.

While maintaining good pressure with your finger to form a seal press the shaft in with firm pressure, this works the grease into all the races and in and around the bearings and packs it properly.  You will feel the grease try to find its way past your finger, try not to let it, make it find its way around the ball bearings if there is too much you will feel it. You will be very surprised how much  grease is used this way.

 

Tank you very much!...
Posted : 20/04/2021 7:08 pm
AlfaXL
(@alfaxl)
Active Member

@clarmrrsn

Looking way ahead to stage 5, step 44 I see the marks, and where they line up facing outward. It would have been good for the changelog to include that as well as the initial picture of making the marks.

Posted : 20/04/2021 10:36 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member

Sometimes you do wonder why the heck you are doing something, or what a part is for, I looked at the thick nylon line with much confusion until I got to the right section.

Then a very small lightbulb appeared above my head.

This post was modified 4 weeks ago by Clarmrrsn
Tank you very much!...
Posted : 21/04/2021 9:55 am
AlfaXL
(@alfaxl)
Active Member
Posted by: @clarmrrsn

Then a very small lightbulb appeared above my head.

Do you have the STL file for your very small light bulb? I feel that I will be needing more than one in the next few days.

Posted : 21/04/2021 4:58 pm
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