1 Topic by dkeeling728 (edited by dkeeling728 2013-06-23 09:44:11)

  • dkeeling728
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Topic: bent y axis shaft.

While in the process of fine tuning x/y adjustments on my SD3, i discovered that my y axis shaft at the back of the machine was ever so slightly bent. i did a forum search and found some threads about the size, but im still confused. i get roughly 6.11-6.17mm range on my calipers, which is quite a ways off from both 6mm drill stock and 1/4" (6.35mm). is there a general consensus on the size of this rod? id like to get a replacement on order before attempting to bend this thing straight.

EDIT: with the rod out of the machine, it was easier to get a measurement, its pretty much 5.99-6.05mm. so 6mm drill rod or hardened shaft should do it. leaving this post so others that search can find the answer easier.

2 Reply by adrian

  • adrian
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Re: bent y axis shaft.

Could take the oppurtunity to switch to 6mm bearings and just use true 6mm smooth rod...

3 Reply by dkeeling728

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Re: bent y axis shaft.

adrian wrote:

Could take the oppurtunity to switch to 6mm bearings and just use true 6mm smooth rod...

i believe i will. what are they? 6x12xwhatever flanged bearings? and a 6mm linear rod? my clumsy caliper measurement couldn't quite get an accurate fit on the bushings in the frame without pressing them out. not something i want to try without replacements in hand. look something like 12.4mm od with 14mm-ish flange.

4 Reply by adrian (edited by adrian 2013-06-23 13:32:29)

  • adrian
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Re: bent y axis shaft.

dkeeling728 wrote:
adrian wrote:

Could take the oppurtunity to switch to 6mm bearings and just use true 6mm smooth rod...

i believe i will. what are they? 6x12xwhatever flanged bearings? and a 6mm linear rod? my clumsy caliper measurement couldn't quite get an accurate fit on the bushings in the frame without pressing them out. not something i want to try without replacements in hand. look something like 12.4mm od with 14mm-ish flange.

The bushings are a bit of an interesting basket case themselves.

Suffice to say, http://www.ebay.com/itm/180915652453?ss … 1439.l2649 will press in with a little effort, or a very light reaming. There has been successful reports of both methods wink

5 Reply by dkeeling728

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Re: bent y axis shaft.

parts ordered.

oddly enough, even with the bent shaft, i still get .01mm accuracy in the y axis, so i guess i'll continue printing while waiting for parts. haha!

6 Reply by dkeeling728

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Re: bent y axis shaft.

new shaft and bearings installed.

had to get a bit rougher than i would like to on a precision machine to get the old bushings out. my c-clamp + wood blocks to press them out idea didn't work, so had to resort to screwdriver and framing hammer. no damage done though. bushings popped right out with a firm whack. reamed the holes enough to get the 6x13 flanged bearings halfway in, then tapped them home with a rubber faced mallet. had a bitch of a time getting the belts and everything back on the new rod, was being extra careful not to go and bend it after all that work, but was successful!

printer seems a bit more noisy on y movements, guess those chinese bearings need some oil! makes me second guess my plans to swap the stock x carrage over to the replacement on thingiverse that uses 8 LM88U bearings... imaging the roar then!

all in all, a worthy repair/upgrade. too late to start a print now, will run the nickle calibration after work tomorrow to make sure i didn't goof something up/have the y belts tightened properly.