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looking for a 624uu bearing..

Posted by shadowphile 
looking for a 624uu bearing..
June 03, 2015 08:20AM
Every single lead I follow ends up back in China... I just need one; there MUST be a US supplier but China floods the markets so bad these days it's getting harder and harder to find non-Chinese parts. I wish I could google with a check-box that indicates 'but not from China' smiling smiley
I've checked a number of robot parts places but no luck yet.
Re: looking for a 624uu bearing..
June 03, 2015 09:15AM
What is your application? Must they be 624uu bearings or can they be other dimensions but still have a inner diameter of 4mm? And is your aversion to using Chinese due to quality or xenophobic?
Re: looking for a 624uu bearing..
June 03, 2015 10:14AM
Tried VXB?


Edited 1 time(s). Last edit at 06/03/2015 10:16AM by madmike8.
Re: looking for a 624uu bearing..
June 03, 2015 04:34PM
can't find anything on VXB.
624uu is the only size I can find that will fit a 3mm filament in a bowden tube extractor. I have too much invested in 3mm to change sizes and a 3mm filament requires a high amount of force in a bowden and a flat bearing might flatten the filament too much with the higher than average clamping force required. Parts from China take so long and I can't afford to sit on my hands for weeks. I am designing my own extruder drive because I can't find a premade design for 3mm AND MK8 hobb which is also desired to get maximum torque from a direct drive.
I hate that I'm stuck with 3mm but the kit I bought for some reason was outfitted for that size.
Re: looking for a 624uu bearing..
June 03, 2015 04:55PM
This one is in New Hampshire.

Re: looking for a 624uu bearing..
June 03, 2015 06:21PM
Dang, got all excited! But these are not 624UU (they are ZZ) and don't have the outside groove. Thanks for looking though, really appreciate the effort! I think another name for the 624UU is U624ZZ, I'm not sure though.
Its funny that lots of Chinese companies offer these but nobody in the US. I think there are some high-end bearing-specific companies that might have something similar but those are over-qualified, expensive, and usually require minimum orders.
ABORTED: Re: looking for a 624uu bearing..
June 03, 2015 08:20PM
I give up, this is too messy and difficult designing my own extruder, gathering the hardware, CADing and printing the parts, etc.
I found a good solution on ebay: link to ebay extruder. It's a little pricey, but in the end may be the cheapest solution for me, who has been struggling forever to get a 3mm Kossel Mini kit to work (a kit I bought as a newbie; see the MakerGeeks Kossel Mini - Junk! thread. The only benefit from that is I am now quite knowledgeable about printer engineering since I have replaced or redesigned virtually every single part of that kit!)

Here is why I think this is best solution, point out any logic I screw up please!
--To maximize torque from my existing direct-drive (as a 3mm requires), I wanted to stick with my MK8 hobb. The 624UU was supposed to give me better backing than a (small) flat bearing.
--But, I found a very nice pre-built for 3mm. It looks like it comes with a larger hobb like the MK7. Normally that would give me less force from the motor, but I realized today that is also spreads out the filament contact, which improves gripping force without destroying the filament. Also, the backing bearing is huge so strong clamping forces won't cause as much pinch-off as the 624UU, despite its groove.
Of course, this puts a bigger load on the direct-drive motor I was trying to reuse, plus the driver and I am intolerant of chew OR skip, but this setup comes with a geared stepper, so I'm back to better grip, stronger torque, a nice quick-release and mounts directly on the frame without a bracket.

I was even today looking at the cost of switching to a 1.75 setup and selling or eating the cost of all my 3mm investments, especially the hotend, which I had ALREADY re-bought to replace the junky one from the kit.

It costs more than I originally wanted but I can keep all my 3mm investment, which saves me money, preserve the possibility of soft materials (which are almost impossible with 1.75 over a bowden), the extruder is a nice looking assembly, dual-spring adjustable-load with quick-release. They also have some nice-looking dual versions, which I am really interested in pursuing once I get normal printing working well. I immediate learned to HATE HATE HATE dealing with overhangs and support material, which always looks horrible after I trim it away, if I can even get to it.
As usual, money solves the problem, if you have it. I'm just really glad they had 3mm versions.
I already upgraded the chassis to all metal corners with 2020 extrusions so it is very square now, quite a beast. Hopefully this means I can run at high speeds too.
Wish me luck.
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