Prusa v2 Assembly & Bearings

I'm trying to assemble my first Prusa, and I chose to do an iteration 2. I'm following the steps as described on the below page:

[reprap.org])


I have some LM8UU linear bearings, but the directions on the page do not mention them. Instead, it mentions snapping on PLA bushings arounds the smooth rods. My first question is, am I correct in assuming that I'll need to put two LM8UU bearings on every smooth rod? If so, am I also correct in assuming that a PLA bushing that came with my kit should be glued to each LM8UU bearing? The parts I'm talking about are in the images below.



I assume that the answer to both of these questions is yes, but if it is, I fear I'm going to have to break one of my X-ends to get them on, and somehow purchase a new X-end. The X-ends that I received were an extremely tight fit and I don't think I'll be able to get them off again! I would be interested in paying someone to print off and mail me one of these if it ends up being the case!



My other concern is, I purchased a mendel iteration 2 plastic parts kit on nwreprap.org, which appeared to have everything I needed. It only came with one RP pulley, but looking on the assembly directions it seems like I need 2... one for the X carriage and one for the Y axis. Does anybody know if I should have received two in this kit? The bill of materials on reprap.org says I need two, but that's for an iteration 1; I see no bill of materials for an iteration 2. The part I'm talking about is in the image below. Same case for this... if I'm missing one, can I purchase one from someone here?




Thank you for reading this! I assume I'll have more questions, but this is where I'm at right now.

Adam

you can fix the tight fit with a bit of sandpaper, just sand the interior side a bit, test, and repeat if its still tight.

I dont think that you have to glue anything. If its too loose i would put some electrical tape around the bearing and test again.

The bearing holder you show looks like it is designed to take an Igus bushing, not an LM8UU bearing. They are 10mm cylinders with a flange on one end that is retained by the hook at the front of the picture.

---

[www.hydraraptor.blogspot.com]

like picklemonkey, im building a prusa iteration2
cant find a full build instruction anywhere (some say v2 but seem to be a mix of the v1?)
does the v2 have 3 or 4 linear bearings attached to the plate?
some posts say 3 and the Josef Prusa Fixed the bed drilling template here shows 3
[github.com]
but build pictures of v2 ive found seem to show 4
does it not matter at all? and if not is there a drilling template for the plate for 4 bearing clamps?
thanks in advance for any help

Thanks for the replies, guys. Here's a picture that most closely looks like my actual setup (I'm at work or would take a picture of the real deal!):




After doing some more searches on Google Images last night, I found a picture of another Prusa with LM8UU bearings that were attached to their plastic parts via zip tie. The pieces were a little different from mine, but overall the bearings fit snugly into my pieces as shown in the picture above. After looking at mine again I noticed a little hole that followed the contour of the bearing that went through the center of the plastic bushing. duh! I'll thread a zip-tie through them to hold them in place.



I am still worried about the RP pulley and an X-end. Can anybody confirm on whether I need one or two RP pulleys, and sell me one if so?

Edited 1 time(s). Last edit at 09/05/2012 12:19AM by picklemonkey.

Yes you need two pulleys, one for the X and one for the Y
As far as the bearing for the bed, the picture you posted is of a PLA bushing. It is designed to snap directly on the smooth rods. I found with my machine I had to slide them on the rods or the PLA snapped in two. I also ran it over a threaded rod a bit to make it fit on my smooth rod.
Also what is your location? If you are stateside i'd be more than happy to help you out with a few pulleys....

Devon

The last photo I posted ended up not coming through, so I just updated the post. You can see the white piece with the two LM8UU bearings in it, which closely represents my bearings & bushing setup. I think I'm good on this one after finding the hole for zipties!

I'm in Kansas City. I have one pulley, so just need one more. I think I'm also in need of a x-end-idler... I'll pay you for your time and shipping if you can help me out!

I am a newbie so whatever I say here might not be accurate.

I am also looking into building a 3D printer and I was considering to build a Prusa It2. As I understand it, this version doesn't need the LM8UU bearings. It replaces them with printed parts.

However, I found out that almost everyone that sells kits for the Prusa online, although they are referring to it2, they sell parts that are designed to work with LM8UU bearings. If I am correct, the version with the LM8UU bearings (or the closest to it) is the ABSPrusa.

It seems though that you did indeed buy parts for it2 (no LM8UU bearings as djamwolfe already said).

That said, keep in mind that I am a newbie, I haven't build anything yet and I am still searching and reading and trying to understand, so I might be entirely wrong.

Sorry for the hijack monkey,

imargonis --

I have a prusa i1 with printed PLA bushings. Honestly as a beginner I wish i'd gone with lm8uu right off the bat. I always had issues with my bed being a little wobbly and I didnt have the smoothest motions on my x axis. I have since started upgrading to lm8uu and it is a world of difference.. Best $20 i spent on this printer so far.

Devon

if you are in kansas city you might want to check out ccckc

[c3kc.org]

know they have a couple of printers they can help you with.

I do know the folks at CCCKC, but I have been given the impression multiple times that they're not willing to help me unless I buy a $30/mo membership with their group. I'd rather give my money to folks who are willing to help me!

picklemonkey -- check your pm

@djamwolfe

Thanks for the info, although I had figured out so much and have already ordered a dozen LM8UU bearings. Is my assertion that the LM8UU version is the ABSPrusa correct?

Because I am still confused as to which instructions I should follow. The Prusa, the Prusa i2 or the ABSPrusa? Everyone is saying they sell parts for Prusa i2 the LM8UU version. But which is the LM8UU version? At first I thought it is the Prusa i2 with a few parts replaced with the LM8UUs. But then I found ABSPrusa that uses LM8UUs and the part list matches the parts of most sellers. In the end I guess they are not so different but they all have slightly different parts and use different lengths of rods/threaded rods which doesn't really help me decide what length I should buy (maybe it isn't so important anyway).

I hope picklemonkey will excuse me for hijacking the thread but I think it is somewhat relevant to his problem. Because when I saw the title "Prusa v2 Assembly & Bearings" it was exactly the topic I was most confused about and still am.

imargonis, one newbie to another, let me share with you my experience so far. Maybe it'll help you out! I purchased a Prusa i2 kit from two separate sources: the plastic was from here (which no longer has any in stock, but the picture shows clearly what I received and am making work), and the hardware was fromanother) which gave me an option to buy the LM8UU bearings as an upgrade. From what I can tell it's completely optional, but definitely recommended. I went with the LM8UU upgrade for my Prusa i2.

All of the hardware that I received for my v2 is listed in the Bill of Materials that's hyperlinked from the Prusa i2 Assembly page that I'm following to build my prusa. The page has no mention of LM8UU bearings, but from what I can tell, the only thing it's missing is that you should put 2 LM8UU bearings on each smooth rod when you mount it to the frame.

Most of the threaded rods that I received in the kit were the wrong size. The bill of materials shows the lengths for the Prusa i1, but in each section of the Prusa i2 assembly page it mentions the real length of each rod that you'll need. I ended up having to source my own mix of metric (imposible to find/expensive) and US/imperial (these are much cheaper and are available at Home Depot/Lowes--go with these!) threaded rods and cutting them/existing rods to length to accomodate for this mixup. It would've been nice to have another 50mm on each of the belts to give me some playing room, and the smooth rods for the Y axis could have probably been another 20mm longer, but otherwise everything seems good with the bill of materials. All said and done, I have probably wasted $50 on hardware and used my dremel more than I would've liked, but none of it was a show stopper.

The only complaint I have with the plastic parts kit that I received is that it only came with 1 RP pulley, but I needed two. Luckily, it looks like djamwolfe is helping me out on this (you're the man!) I'm on the "Assembling the Z-Axis" step of the build so I could have other problems later, but all things considered, I had most everything I needed to get started and no issue has been too expensive to correct.

That's what I've learned so far, I hope it helps!

Adam

Edited 1 time(s). Last edit at 09/11/2012 10:18AM by picklemonkey.

I assembled an i2 following this manual:
[garyhodgson.com]

just be aware, depending on the plastic kit that you bought some steps might be different. Just use your creativity and intelligence to adapt

I did that and looks like it came ok. In waiting for the hotend and electronics.

@picklemonkey
@nic0laz

Thanks to both of you for all the info.

I received yesterday the plastic parts I had ordered (I bought them from user avdwege2003 - I am no expert but they seem to be of very good quality). I intended to follow the instructions on Prusa Mendel Assembly (iteration 2) but from a 1st quick look some parts are a little different. Of course this is no surprise, I expected so much. I 'll just start the assembly (as soon as I cut the threaded rods and find me some smooth ones) and I 'll deal with any inconsistency when it comes up.

@imargonis, i got my plastic parts from avdwege2003 too, all good!

i used this instructions:
[garyhodgson.com]