How to forget about circle problems for ever.... (Page 1 of 4)

That's a lot simpler than trying to replace the bushings at each end with a bearing, and has the same effect.  I had wanted to change the bushings because it seemed like so much tension pulling the rod down on the bushing and forward at the same time made it harder to turn and contributed to Y skipping by the time you dialed out the backlash.

I just replaced my pulleys with metal ones and ran into the same issue. Hate to say it but BFI (Brute Force and Ignorance) worked well. I just pulled the rod out from on side slamming the stuck pulleys into the bushing. (I had flange bearings on stand by just in case)

What's the trick to getting the pillow block, with bearings, onto the rod? Sand the rod? Dremel the bearings? Heat the bearings?

how did you go about attaching the pillow block to the back of the case?

Thanks, I guess that was a stupid question

got a link to metal pulley's so i don't have to buy a complete replacement pack from solidoodle?

So.... does this mod really end all circle problems?

My Y rod (the one in the top rear of the case) has an approximately .3mm wobble in it.  Is this significant enough to be causing my circle problems?  (I've checked belt tension, etc.)

I'm thinking about doing this mod anyway...I've already ordered the bearings.

Well, I'd have anticipated further feedback from the wider audience by now, but from my perspective, as stated, I haven't had a circle problem despite wickedly asymmetric belt tensions since early last year.... and I print everyday pretty much.  Those that I know that have also done it have also never mentioned a circle problem, so one can only presume...  Maybe someone else can offer feedback

Not sure what you mean, as the SD3 doesn't have bearings. Closest it has is self-aligning sintered bronze bushings.

These are not particularly adequate for the application at hand (as they will incur drag on the rod and their casing as they self-align" - the point here is to hold the rod rigid with support just like a linear block does... ) , so I would recommend springing the $5 and getting the ones stated - otherwise YMMV on if it helps or hinders......

Adrian I will try this mod and give feedback.

My problem is I tried the true circle re alignment video but my pulleys won't slide freely on the y drive rod when loosened, they like dug into the rod or something. So now after y rod calibration i think my y axis is worse than before. Can't get the dang rod to stay center when sliding the carriages because the pulleys will only go an inch on the Rod before catching and scraping. I have a new y rod on the way. Until then I will try this mod out.

I did a similar mod but used two bearing supports rather than one. Main reason I did it was the 6mm shaft was not straight and sliding around in the bushings pretty much assured I was never going to get truly round prints off the machine. I forget exactly what I used for bearings but I believe they were Align mainshaft bearings from a Trex 500 or 550 RC helicopter, readily available at the local hobby shop. A few minutes in Sketchup to create the necessary blocks, quick print, then disassemble and install.

As part of the upgrade I also did the conversion to 16 tooth GT2 pulleys and belts on both X and Y axis. Put it all back together and did the necessary adjustments and calibrations, haven't touched it since (close to 2 months now) and still getting flawless prints with nice round circles.

I use this printer a LOT, right now it is nearing the end of printing a full set of plastic parts to enlarge my 3DR delta printer, the SD3 has been running nearly nonstop for over 2 days now and all I do is swap the filament roll when needed.