Ok I have a solution. You need to buy some 1.75 bowden tube. You then can take the 3.00mm hexagon off. Then take the 1.75 bowden tube and insert it into the extruder mount. It will be tight but it will fit. Push it to its just short of the hobbed bolt. You then will want to cut the bowden tub so its flush with the bottom of the extruder mount. Then you will need to take a razor and clean the inside of the bore of the tube so the filament doesn’t get stuck. You can put the entire extruder assembly together now with the tube in place. This will eliminate the chance of the filament kinking and also will let you probably use flexible filaments without any issues if you have the tube all the way up near the hobbed bolt.
Cool I was about to post the exact same thing. If you look at my previous post with the pictures you will see the problem. Here are some pictures of me doing exactly what jprochnow is describing. I cut a piece of 1.75 mm PTFE tube and shoved it into the Drive Mount. Since then I have printed a few objects without any trouble. I should clarify that I am also using a 1.75mm Budaschnozzle. That means From the time the filament goes through the hobbed bolt and idler bearing my filament is held snug into place with 1.75mm parts. So for those of you who want to do this same mod, I will make this clear. You will need some 1.75mm PTFE tube to shove into the Month like I did here. Then you will need a 1.75mm hot end. That hot end could be budaschnozzle, E3D V6, or Hexagon. It doesn’t matter. As long as the Hot end is a 1.75mm hot end. If you look on Thingiverse.com you will find many adapters for those Hot ends to attach to the TAZ.
I have two TAZ printers and Several Print heads that I swap out all the time depending on my need. I use several different Hot Ends with different Nozzle Diameters. Now I have this Print head setup to use my supply of 1.75 filaments.
A short word on the different Hot Ends for those people who might want to buy a new one. Budaschnozzle is my least favorite but if you keep it clean and cool it will work I have destroyed two of them trying to dismantle and clean. E3D V6 is my favorite because I can put anything experimental through it. It is easy to dismantle and clean if I have to. Hexagon is new to me but so far I am impressed.
So the general idea is 1.75mm doesn’t play well in a stock TAZ 5 with a 5mm nozzle, correct? I’m asking because my new TAZ 5 arrives tomorrow and I have no idea what I’m getting in to with this printer. I currently have a Robo 3D R1 that has worked flawlessly since day one. I wanted to try a Lulzbot after reading so many good things about these printers.
I have been running 1.75 mm PLA filament without issues for multiple prints now after loosening the screws to approx. 4mm spring length as some other post in the forum suggested. Sometimes there are issues with the filament getting stuck because it curls up during the feeding. But as I said, I did a couple of prints without any issues now. Pretty much standard settings in Cura and meticulous calibration.
Thanks for the bowden tube suggestion. I replaced my hexagon 3mm/.35mm hotend with an AO edition 1.75mm/.4mm version, and was getting tons of kinks. The bowden tube solved that problem nicely!
Hi, newbie here, but in the same situation as everyone else i.e. loads of old rolls of 1.75mm filament and now have a Taz 5.
I find that it works best with light pressure from the extruder filament clamp as suggested earlier, 1.75 set and then the key thing to prevent it binding/grinding up the filament is to disable retraction. I’ve tried limiting retraction to just 1mm but the act of the extruder backing up seems to induce a massive level of unreliability. I just use the old rolls for prototypes or contiguous models where the lack of retraction isn’t noticed.
I’ve tried going dual with 1.75mm filament and the unreliability mentioned above that is incurred on extruder change mean that it is so unreliable it isn’t worth bothering with.
Candles.
Thanks for this post! I would not have sprung for the TAZ 6 if all my leftover PLA would have been wasted. It’s working great for me with just the edit you suggested. w00t!
I’ll just add my experience to this discussion. I’ve been printing with 1.75mm petg lately, and it’s been mostly working. If a print doesn’t last very long, and I keep the retraction minimal, I usually have a good print. However, the failures are still way too frequent. Ultimately, the filament folds in on itself, and jams up in the extruder body.
I took some advice from an earlier post, and picked up a bowden tube. I opened up the channel in the body to 4mm, and installed the bowden tube piece. So far, I’ve had several long prints complete successfully on the 3mm extruder. No kinks or jams!
I’m still going to build a second extruder body, exclusively for 1.75mm, so I can quick swap between the two sizes.
I have one Taz 5 running with the 1.75 bowden installed in the stock extruder body as well. Many hours of printing and no problems. From what I have read, this is the best way to run 1.75 on a Taz or Mini.
BTW, I didn’t have to drill out the extruder body. The bowden tube that came with my E3D V6 hotends fit the stock 3mm filament path in the extruder body perfectly. I can pull the bowden tube out from the top when I need to run 3mm and push it back in for 1.75 printing.
I just tried the Bowden tube method with my Mini and it worked flawlessly. Just slipped it in from the top, cut it at a 45 degree angle, and I’ve finally managed success with PLA, ABS, and ColorFabb XT. Thanks the idea!
My Taz6 showed up Friday but my 3mm filament doesn’t get delivered until today (Monday) so I gave printing with 1.75 a whirl. It worked great which is awesome because I had bought a whole slew of 1.75 filament for my other printer in the last month before deciding to upgrade. I didn’t need to calibrate anything other than adjusting the filament diameter in the cura window.
Like others have said I used a small piece of 1.75mm bowden tube that I cut at 45* angle which I inserted into the extruder body. The 45* portion goes up top near the hobbed bolt for any newbies wondering. It was a pretty tight fit for the bowden tube but I managed to get it in and shouldn’t have too much trouble getting it out when I swap back to 3mm filament.
Here is a pic of my prints, they are soft jaws for a 4" bench vise. No post processing was done on the finished piece. This Taz prints butter! 
The only problem I have had (thus far) has been that the nozzle oozes a little bit during bed leveling and it is enough to prevent good contact. I’ve adjusted the initial retraction in the start script but it seems to be the material in the nozzle. It’s very tiny but enough to be an issue - it interferes with the conductivity needed for auto-bed-leveling.
Adjusting the tension made a significant difference.
Update: I edited the wipe code to perform most of the wipe, drop temp some (eg 170C to 150C for PLA), then complete the wipe. This has solved the oozing during the auto-bed-level process on the TAZ6.
I have several spools of 1.75mm laying around. Where is the setting to change to 1.75mm on the Cura software?
In the latest version of Cura LE you can set the filament diameter under custom settings/material/diameter Or just type dia in the search box in Cura.
Thanks! Just learning this software!