Hey all, I just recently started building my own Prusa Mendel, (with wades extruder, buddaschnozzle, and Gen7 electronics) Forgive me if this is commonly known already, but I've come across a couple of issues with the Prusa i2, and wanted to check to make sure I wasn't missing something blindingly obvious. First off, the BOM for vitamins on the prusa page lists an M8 grubscrew. which I cannot find used anywhere. [reprap.org] Also, there are 4 small springs required for the wades extruder, as well as 4 very long M3 bolts (which simply don't exist, will have to use M4's) and 2 larger springs for use as Z axis screw preloaders, which aren't listed on the bill of materials anywhere. Secondly, there is something wonky with the X-end motor mount. Namely, it doesn't line up at all with the pulley or the carriage, and I needed to pack it out with washers to get it to work at all. plus it seems like the motor mount for the iteration 1 was a much better design, having the stepper hanging off the side would add a fair whack of torsion to the whole x-axis wouldn't it? Does anyone know why this was changed? So, am I missing something really obvious, or are there actually a few mistakes. https://reprap.org/forum/read.php?151,180638,180638#msg-180638 Wed, 16 Sep 2026 09:25:14 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?151,180638,181138#msg-181138 https://reprap.org/forum/read.php?151,180638,181138#msg-181138 TopherMan General Mendel Topics Fri, 01 Feb 2013 10:02:20 -0500 https://reprap.org/forum/read.php?151,180638,181036#msg-181036 https://reprap.org/forum/read.php?151,180638,181036#msg-181036
I guess fair enough re the optional thing about the springs.

yeah I agree about the press fit issue too.

and as far as the belt and ends not lining up, turns out that was my own doofus fault.
I built my unit using linear bearings, and the place I ordered my rails and bearings from provided me with LME8UU's, because of this, the xCarriage I had bought, didn't even come close to fitting properly (as I was foolish enough to not check all the specifications correctly).
This also threw everything else out of alignment (even after a little kludging)
I'm currently in the process of getting that fixed up, so all good.

edit: I realised I might sound a little critical of the whole thing, which was not my intention, it's really all quite clever, I just had a few queries is all]]> cognismith General Mendel Topics Fri, 01 Feb 2013 04:35:02 -0500 https://reprap.org/forum/read.php?151,180638,180844#msg-180844 https://reprap.org/forum/read.php?151,180638,180844#msg-180844
As far as the extruder, if you're in the States you can find really long M3s on McMaster-Carr, but personally, I recommend using this extruder: [www.thingiverse.com]. In addition to using M4s, it has a couple nice additions like a lever for reloading and a guide on the idler to keep the filament centered.

The springs for the carriage are not totally necessary; they really reduce backlash in the Z direction, but as long as you don't implement any hopping or printing parts individually (basically, you only ever go up while printing, never down) they aren't a huge deal.

Finally, with respect to the X motor, it doesn't seem to torque the system too much; there are two smooth rod and two threaded rods keeping the x carriage oriented properly, and that's more than enough to keep the carriage stable. If there's anything annoying about the version 2 carriage it's the press-fit, which requires smooth rods of perfect length, and a high quality print for the ends.]]> TopherMan General Mendel Topics Thu, 31 Jan 2013 11:46:54 -0500 https://reprap.org/forum/read.php?151,180638,180710#msg-180710 https://reprap.org/forum/read.php?151,180638,180710#msg-180710 The long M3 bolts are as rare as hen's teeth so I too am puzzled by their use.
The "Z" springs are optional - I haven't used them or the extra nut in the extrusion but some do.
Not sure what the problem is with your X end motor without seeing a pic. Have you fitted the pulley with the teeth closest to the motor?]]> waitaki General Mendel Topics Thu, 31 Jan 2013 01:38:17 -0500 https://reprap.org/forum/read.php?151,180638,180638#msg-180638 https://reprap.org/forum/read.php?151,180638,180638#msg-180638 I just recently started building my own Prusa Mendel, (with wades extruder, buddaschnozzle, and Gen7 electronics)

Forgive me if this is commonly known already, but I've come across a couple of issues with the Prusa i2, and wanted to check to make sure I wasn't missing something blindingly obvious.

First off, the BOM for vitamins on the prusa page lists an M8 grubscrew. which I cannot find used anywhere.
[reprap.org]

Also, there are 4 small springs required for the wades extruder, as well as 4 very long M3 bolts (which simply don't exist, will have to use M4's)
and 2 larger springs for use as Z axis screw preloaders, which aren't listed on the bill of materials anywhere.

Secondly, there is something wonky with the X-end motor mount. Namely, it doesn't line up at all with the pulley or the carriage, and I needed to pack it out with washers to get it to work at all.
plus it seems like the motor mount for the iteration 1 was a much better design, having the stepper hanging off the side would add a fair whack of torsion to the whole x-axis wouldn't it?
Does anyone know why this was changed?

So, am I missing something really obvious, or are there actually a few mistakes.]]> cognismith General Mendel Topics Wed, 30 Jan 2013 18:02:11 -0500