Prusa i2 BOM

Hi all, I was looking at the Prusa page on the wiki recently (3 seconds ago) and noticed someone made some major revisions, and while I agree that the page was in serious need of some TLC (tender loving cleanup) some of the things on the new list make no sense. Firstly, 10 LM8UUs aren't enough (with the printed parts listed you need at least 11). Secondly, what in the world would you need a M8X50 grub screw for? Thirdly, 50 M3X20 seems a little excessive (I've built multiple Prusa's and never used more than 30). And fourth, it seems to me that 405mm would be pretty long for the Z smooth rods seeing as they already stick out a bit as is.
There were multiple other things, like inconsistencies with the source BOM and such, but those are my main concerns. I run a small business selling reprap doodads and just would like to know that I'm not going mad, because this "new" BOM is causing a lot of confusion for both myself and my customers.

I have only ever use 10 LM bearings as I only use 3 on the heated bed not four. I find it runs nicer and is easier to centre and I have made about 30 of them to date with no problems

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Experimenting in 3D in New Zealand

I suspect that the intension of the BOM having 50 instead of 30 M3x20 bolts is that a box of 50 will cost you a lot less than getting 30 individual bolts.
It is always good to have more than necessary bolts/screws/nuts/washers etc than having to drive back to get more.

1. Has been answered Prusa i2 only uses 3 bushings/bearings for the print bed.
2. For the extruder I believe.
3. All bolts and nuts are given to the cheapest option. 40 nuts will cost the same if not more then 50 and allow you to lose a nut or two. Plus Prusa i2 moves away from M4's in favour of M3.

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My Reprap blog

jds-reprap.blogspot.com

Maybe the M8 x 50 grub screw is for the X Idler? Simply sawing off 50mm from leftover lengths of framing rods suffices.

derevaun Wrote:
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> Maybe the M8 x 50 grub screw is for the X Idler?
> Simply sawing off 50mm from leftover lengths of
> framing rods suffices.


It will be but I use a 50mm leftover peice of threaded rod with 2 nylock nuts instead same for the wades

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Experimenting in 3D in New Zealand

Hi guys! I have a question related to this topic. Last year i purchased a hardware kit for the iteration 1 prusa, This year i decided to actually finish this project. I purchased the printed parts for the iteration 2, I was wondering how much diffrent the hardware kit actually is? I am also wondering why alot of the parts have been replaced. Comparing the list i notice that i now need 2 m3x8 grub screws, 50 m3x20 bolts and 1 m8x50 grub screw, Are these necissary additions? Thanks guys.

The M8 x 50mm grub is for the X idler You can use a piece of all thread but for the buck or so that it costs for the grub it's easier than cutting it from stock plus there is a socket head you can use to tighten it.

As stated above, it's easier to package and buy the screws in a quantity of M3 x 20 mm of 50 in many cases. Use them for the bed mount, printed couplers if you use them, endstop mounts, extruder mount. I count about 28 on the i2 at my desk right now. You can use the extras to mount your electronics, display and the like.

The M3 x 8 grubs are for the belt pulleys.