Eric Lien   Now what?

@Eclsnowman Now what? How can I fix this situation?

ABS?

PLA or ABS?

PLA

CA and a clamp. Or re-print.

Re-print exactly the same? What is CA?

CA = cyanoacrylate = super glue

I will try reprinting it a few times before I use super glue. That just doesn’t seem right. :slight_smile:

I use ABS so I can acetone soften the hole before pressing in the bushing. It also acts to glue the parts in. If you stay with PLA put sand paper on an appropriate sized cylinder (sockets work nice), and open up the hole if your printer is making them underside.

I have tuned my printer to the point I am usually 0.1 to 0.15mm from nominal now. So I haven’t run into the cracking in a while. Also I would consider PETG for the carriage. It has incredible interlayer bonding so may perform better. And has a shrink factor similar to PLA.

If you use ABS acetone on a q-tip works great to soften the hole before pressing it in. Just get the q-tip wet with acetone and wipe it on the mating surface, a few applications are required. Once it is softened it you can press it in like a hot knife through butter.

A Dremel sanding drum worked for me. You should not have to apply so much force to get the bearings in, doing so will crack the housing and make it hard for the bearing to align. When you print you might try higher fill ratio as well.

If you do re-print it, make sure you make the hole a bit bigger. You can find the cad files for my printer here: https://cad.onshape.com/documents/a45f6c99e2154f3b94955175/w/443cf4d7046e41d1b21d5426

Go ahead and open up the carriage and adjust the holes to account for the error.

If you don’t want to use my version, you can adjust Eric Lien’s version in designspark, the files for which he kindly provided.

@Vic_Catalasan I like high perimeter medium infill over high infill.

Is there a FAQ or readme on the github on assembly techniques? I think this is the third time this has been reported, and it’s an easily avoided problem if the user knows what to do.

@Jeff_DeMaagd no readme yet. Seth was working on it, but has had things come up. I would love it if the community could help on the assembly instructions side. I think many have taken pictures and notes… But with my new job I have less time than before.

+1 on @Eclsnowman 's suggestion for using a Q-tip with acetone (if ABS). I did the same thing to “weld” some plastic on a broken tripod–works like new! Also, I have not tried it myself (yet), but for PLA, perhaps a hot glue gun might work?

@Eclsnowman Understood. I won’t be able to contribute for a while either.

I got this working. I ended up wrapping some sand paper around a socket and was able to sand away enough to allow the bearings to fit. I wasn’t patient enough the first time of sanding and cracked it again. Good thing I printed 2 of them. :slight_smile:

How easy should these slide around? Will running the gcode break in help loosen these rods and bearings up? It definitely doesn’t move around very smooth at this point.

I just checked the diameters of the bushing holes on the carriages. They are 15.9mm (Bushing is 16mm). If it was printed on a calibrated printer, the bushing should slip right in with a firm push with a thumb.

For anyone having fitment issues, please do not force them in! Use sand paper to sand the diameter of the hole down until you are able to push the bushing in place with a thumb/finger. Use the 8mm or 10mm rod to wiggle the bushing out if its stuck and repeat the process. You only want a firm fit. Not a super tight fit. Remember, that bushing needs to swivel 5 degrees inside its black sleeve in order for the ‘self aligning’ feature to do its job. A super tight fit will turn the black sleeve into a clamp preventing the bushing to swivel around.

Aligning takes some time. Lots of possibilities for compound errors. Start by aligning all the upper rods. Then take the carriage to each corner by hand and feel for binding. Adjust as needed on the lower rod so it moves smooth, then re-run the break-in. Then recheck to each corner by hand feeling for binding. Lather/Rinse/Repeat until it is smooth. Once it is right… You will know.

Best of luck.