My extruder broke again today. Not even the epoxy could provide the strength. My cheap hack to hopefully print long enough to make a replacement. Two zip ties. One around the base holding the idler to it’s hinge (the part the broke), and one around the idler assembly holding the idler tightening screws in place.
What broke? You know why it broke? Is a simple re-print all that’s needed to fix it?
Ill take a guess: What always breaks on those things, the ‘guidler’; overtighten those screws and the thing can split at the edge.
I see no springs on the guidler - those are absolutely vital for reliable operation.
Sharp eyes @Thomas_Sanladerer
Hmm ok; good to know. I’ve never used the “guidler” versions, filament was typically mounted above my machine and hob deep enough to never had experience with this. I did notice lack of springs though. It seems like such a silly thing, but those springs really increase the reliability of filament driving.
Personally I hate that design. I went through 5 of those all of various designs (springs included) I found the four bolt design works the best. Still using the first one I printed almost 5 months ago maybe 6.
You will need to print a hole New extruder to use the four bolt tensioner but in my opinion it’s worth it.
Get bigger zip ties and really wrench them on there enough to print out another one. You can take 2-3 big zip ties and wrap them length wise around the extruder behind the big gear and under the stepper, around the tensioner, and it will put even force on the extruder tensioner (broken part) so you can print a new one or the other version, that’s what I did.
and yes springs are a vital part of that assembly. There good to have on the four bolt version as well.
@Kris_Schnell you see that a lot because a lot of us built our own, no kit, no help, and these parts can wear out over time. You don’t really see anyone else with pre-assembled, or kit-built printers really saying this often (like Ultimaker users, barely ever see them say something is wrong).
I totally get the concept of printing our own parts for printers but really, there is no substitute for machined parts in the right places. Unfortunately, that require standardization to get the volume high enough to make them cheap. Which is why we print them. :). The extruder is one area that could be standardized as nearly all bolt onto a nema 14 stepper. The hot end mount is another - I’ve got a machined E3D hot end and love it.
@Clint_O_Connor , most of them use Nema 17’s. There are a few that use Nema 14’s (RepRapPro), and others that use a Nema 17 with a planetary gear drive. People also use hobbed bolts, machined gears, dremel bits…there are so many variations each with their own merits.
@Clint_O_Connor
LoL - so much for a standard! 
I use Nema17’s on all of my 1.75mm bots, and Nema17 Gearheads on the 3mm’s.
I stand corrected on NEMA17s for extruders - still think a good design and machined parts (open sourced) would be accepted by most printers.
@Kris_Schnell I bought a Solidoodle 3 ($799 for 8x8x8 print volume) and it came assembled and ready to print. (Solidoodle 2 $499 for 6x6x6 inch volume). For myself, I considered it a great way to start printing while waiting for my Rigidbot (kit). I’ve already printed several replacement parts to improve the S3 so I’m learning while I print. It seems to be a really solid basic and affordable unit.
To clarify my extruder’s failure:
The idler hinge broke - probably from over-tightening, but I believe this block was printed at 25% infill, contributing to it’s weakness. I attempted to epoxy it, but still experienced another failure.
I can’t comment about springs being required for idler - it was delivered in mostly this condition to me, a kind friend printed it for me to get my printer working. I’ve had mixed feelings about how best to the solve the problems I’ve faced. Mostly I just want to get to a replacement that will work. I’ve been tempted to get a water-jet cut extruder block and be done with it. But I have what I have to work with.