Recently I fitted 608-bearing constraints near the top both of the Z-axis threaded rods on my modified Sells Mendel, in case I could gain any small additional increase in accuracy by stabilising them, and thereafter a strange knocking/crunching noise has been coming from the Z-motor bracket whenever it's in motion, seemingly centred on the pulley 608 bearing, yet as far as I can see from outside, nothing has come loose, there are no metal filings appearing around there and the Z-axis continues to function normally noisily. Video on Vimeo (16 seconds long) The noise continues even if I remove the Z-rod constraints, and I've tried adding a few drops of oil on top of the bearing hoping they would seep through the metal shield, though I can't see that any has been lost anyway. I'm glad that it still seems to be printing OK, but a bit puzzled and worried about the noises. This printer has gone through about 6 or 7 kg of plastic over the last 1.5 years and is still on its original Z-belt, which looks just fine, so I'll be very surprised if the 608 bearing has worn out in some way, but perhaps it had a rare manufacturing defect (I do seem to be jinxed for that sort of thing). I'd rather not have to spend hours unnecessarily disassembling my whole X-Z axis complex, so wondered if anyone has a better guess than me as to what's going on here. :S tl;dr does anyone recognise the noise in that video? https://reprap.org/forum/read.php?151,155199,155199#msg-155199 Mon, 20 Jul 2026 21:44:37 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?151,155199,158266#msg-158266 https://reprap.org/forum/read.php?151,155199,158266#msg-158266 Time for even more dis-assembly. :(]]> 4ndy General Mendel Topics Tue, 02 Oct 2012 18:49:15 -0400 https://reprap.org/forum/read.php?151,155199,155548#msg-155548 https://reprap.org/forum/read.php?151,155199,155548#msg-155548 I think the 'thunk' is from when the tensioned belt finally slips into place and it's somewhat like strumming a guitar.]]> Buback General Mendel Topics Thu, 20 Sep 2012 12:07:58 -0400 https://reprap.org/forum/read.php?151,155199,155372#msg-155372 https://reprap.org/forum/read.php?151,155199,155372#msg-155372 While removing them doesn't stop the noise entirely, it does reduce it, so I think I'll leave them off from now on and try my best to replace that bearing without losing my x-levelling whenever I have time to.]]> 4ndy General Mendel Topics Wed, 19 Sep 2012 13:49:00 -0400 https://reprap.org/forum/read.php?151,155199,155222#msg-155222 https://reprap.org/forum/read.php?151,155199,155222#msg-155222
The bearings most folks use around here aren't what might be called expensive, so perhaps its time to consider doing a bit of replacement maintenance?]]> xiando General Mendel Topics Tue, 18 Sep 2012 16:22:09 -0400 https://reprap.org/forum/read.php?151,155199,155199#msg-155199 https://reprap.org/forum/read.php?151,155199,155199#msg-155199 608-bearing constraints near the top both of the Z-axis threaded rods on my modified Sells Mendel, in case I could gain any small additional increase in accuracy by stabilising them, and thereafter a strange knocking/crunching noise has been coming from the Z-motor bracket whenever it's in motion, seemingly centred on the pulley 608 bearing, yet as far as I can see from outside, nothing has come loose, there are no metal filings appearing around there and the Z-axis continues to function normally noisily.

Video on Vimeo (16 seconds long)

The noise continues even if I remove the Z-rod constraints, and I've tried adding a few drops of oil on top of the bearing hoping they would seep through the metal shield, though I can't see that any has been lost anyway.

I'm glad that it still seems to be printing OK, but a bit puzzled and worried about the noises. This printer has gone through about 6 or 7 kg of plastic over the last 1.5 years and is still on its original Z-belt, which looks just fine, so I'll be very surprised if the 608 bearing has worn out in some way, but perhaps it had a rare manufacturing defect (I do seem to be jinxed for that sort of thing).
I'd rather not have to spend hours unnecessarily disassembling my whole X-Z axis complex, so wondered if anyone has a better guess than me as to what's going on here. :S

tl;dr does anyone recognise the noise in that video?]]> 4ndy General Mendel Topics Tue, 18 Sep 2012 13:48:42 -0400