They can be machined, or you can take the FreeCAD models here and export them as printable STL files. They are available as STL files here as well, or in the parent directory: http://devel.lulzbot.com/TAZ/Guava/production_parts/printed_parts/TAZ_printers/
Were they made of aluminum to add significant rigidity to the system? Is there any downfalls to printing these parts, therefore, why didn’t lulzbot have them printed?
Which sub-category is the STL located because I looked through that list heavily before looking in the other source folders for a PDF.
2con
I actually asked Lulzbot about this a while ago via email as I’m building my own TAZ. I was asking whether they’d be willing to sell me a set of the TAZ 4 aluminum parts. They responded:
Unfortunately we will not be able to sell you those parts. The only parts of those that we have here are designated for our production runs. The only good news I have for you, is that the x end plates that are printed are just as good as the aluminum ones. We stopped printing the end plates just due to production/time constraints.
So what I ended up doing was printing x end plates. They seem reasonably sturdy but I don’t have my whole printer together yet, so I can’t say for sure that they work without any flexing. For the y-axis ends, I was unable to print them on my current printer (build area is too small) so I ended up making these out of aluminum using a jigsaw, drill and a hand file. It took quite a bit of work but I think they turned out ok. If my build area were big enough I’d probably have tried printing some first.
Thanks for the responses about the end plates. I thought I was going to see a roadblock in my upgrade plans. 
Nopick - there’s an STL here:
http://devel.lulzbot.com/TAZ/Guava/production_parts/test_parts/x_end_concept/
It’s called X_end_plate… 
Looks like the STL already has the proper sizes to allow for the heat-set brass inserts but you might want to double check that!
Great! Thanks.
Thanks guys! This is almost bad news to me because i’ve generally “put the order in” for some custom made X_End Plates… Oh well, stiffer machine…
Unextas suggested a great idea, if your doing this upgrade(or plan to also upgrade for auto level and dualies), switch your IGUS bushings with lmu10uu bearings. Find them on eBay for a decent price!(not sure of china quality 
)
http://www.ebay.com/sch/i.html?_odkw=IGUS&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR12.TRC2.A0.H0.Xlm10uu&_nkw=lm10uu&_sacat=0
Those bearings will groove the stock shafts. I had to remove mine.
Good to know! What is a better choice?
Not off hand. You just need some hardened rods that are designed for bearings.
Sweet here’s a link for everybody else from mcmaster carr. 6112K47: http://www.mcmaster.com/#catalog/120/1091/=sv79v5
500mm 10mm DIA.
UPDATE:
Credits go to unxetas for this one.
I got my lm10uu bearings from China yesterday and the hardened shafts from McMaster today. They fit fine on the shafts but will definitely be louder than the IGUS bearings! They will also absolutely need grease to function and stay smooth.
Just waiting for one last package from 2con to start my conversion! I’m printing all new bearing holders today just so I can start preassembling stuff without taking the printer apart. That will make it so I can print any last minute emergency bits while already assembling the new parts, and also means I get to keep the entire old X (minus the carriage) and Z axis as spares…
I’m also adding motor dampers to the stepper motors which should quieten everything significantly and reduce vibration/resonance… Since the new bearings will be louder, I’m hoping the quieter motors will sort of cancel out any increase in noise
Cork sheets? or something else for the dampner?
So the TAZ 4 double bearing holder are different from the TAZ 2. Print 2 for the z Axis movement here:
http://download.lulzbot.com/TAZ/4.0/production_parts/printed_parts/TAZ_printers/double_bearing_holder/
Unxetas and I split my McMaster hardware order! Nobody needs 100 screws of each type for just 1 printer. Go lulzbot forums! 
2 or more members interested in this upgrade could do the same as us. 
2Con
Piercet, they’re actual stepper motor dampers from astrosyn - http://astrosyn.com/section.php/44/1/vibration_dampers
Astrosyn only sells in packs of 10 I believe, but there are other sources like tridprinting.com… There were also a few group buys kicking around on other printers’ forums, but the prices are all similar. Do some YouTube searches for astrosyn dampers I’m sure you’ll find some comparisons
Huh. I’ll have to try some of those too maybe. The only worry would be if they are stiff enough to avoid shaft deflection on insanely tight belt printers i guess.
They are very stiff - some folks had tried cork or silicone layers and this is at least an order of magnitude stiffer than either of those. I’ve seen great results on the delta style printers, so I’m hopeful it’ll work well here - I’ll post an update when they’re installed, hopefully in the next few days!
My x end plates are finished but I have 1 concern.
When you place them side by side you can feel a slight difference in thickness. Is this a critical dimension? I did not have the correct thickness of material to start.
The spec says to be 1.88 and I’m at probably 1.65 and 1.75
I could potentially shave one plate down so they both match in thickness, but is having them they way they are going to cause any issues? Or should they be remade starting with the correct thickness?
2Con
2con - from my understanding of the way the assembly goes, no I don’t think it’ll matter too much! I think the bearing holder and the Z nut mount both mount to the same side of the plate, and those are the critical items… The X motor and idler mounts will be at slightly different distances from the center but that shouldn’t affect anything!
Although, I hope you mean 0.188", 0.165" and 0.175" 