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What are the names of the ball screw bearings and centre bearings?

I know the outside bearings are LM12UU but what about the ballscrew bearings and the bearings on the quick change head? My y axis is shot. I have already ordered outside bearings but am down till I can replace ballscrew bearings as well. Quick change head is smooth but noisy. I plan on installing quality bearings in the hope of avoiding further issues.

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Hi Guys, I need to know how to properly remove the ballscrews to send them in to be repacked - I dont want to just start removing screws and end up with a mess.. Please help?

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I just posted access to some of the guides the team is working on for you. They are still in progress and weren't quite finished yet. These should help you get there. To actually remove the ballscrew you'll have to remove the pulley. This has to be done with heat, they are loctited on (if you have a later machine). A lighter and some time rotating the pulley will do, but it takes a minute to get hot enough. Make sure you remove the belt first. Back out the set screws (2) and pull off the pulley, paying attention to its original location. Clean the end while hot then just remove the flanges and bearings and slide it out through the top.

The guides can be found here under "In progress": Trouble Shooting Resources

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Ok, that's a different issue. The numbers I gave you are for the bearings on the ends. For the ballcrews the entire piece is the assembly, the bearings rotate on the shaft directly and are free running (the balls have nothing holding them in once the shaft is removed). You replace the balls themselves when needed, but for many years of hard use nothing more than cleaning should be necessary. Because the balls are held in place by the ballscrew shaft they require a hollow transfer shaft to take them on and off the shaft when you want to avoid re-packing. They can be re-packed by hand easily (this is how it's done), but you'll need a written guide and a transfer shaft to do so. I've been planning on making a guide on how to clean them out and re-pack them, but I haven't had a chance. I'll work on making time in the future. The seals can be removed and replaced without removing the ballnut from the ballscrew shaft, I'll put that on the list of guides as well. For now, If you're willing to send the ballscrew parts back in, the BoXZY team will replace out the balls and seals and re-pack them for you for no cost. I've already contacted them. The dry bearing sound in the LM12UUs does makes sense. I'd grease them with engine assembly lube if they seem louder that normal. Check out Thrinter.com when you get a chance, he created a 3D print for a ballscrew transfer shaft on BoXZY.

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Thanks. I'm going to bring the assembly in to the bearing supplier when the LM12UUs show up and they can educate me further. I will probably need a new shaft as because I thought it was done I attempted to remove the flange from the end. The plastic is damaged. For now I'm ok getting a replacement locally to save time unless it is proprietary.

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Now have better understanding of ballnut assembly but a guide on repacking after cleaning would be great. I'm going to put a question up in the new maintenance section asking for specs on all the bearings and ballnuts. I've got two nice Japanese LM12UUs and a bag of balls to put in the ballnut assembly but without the specs couldn't get a whole new assembly or replacement endcaps (wipers?). In retrospect I would probably have a repacked assembly already here or on the way if I had accepted the offer to send it back to team Boxzy. Regardless, knowing the parts to order is a huge help.

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The sleeve bearings are the LM12UU, the flanged bearings are LMK12UU. The bearings for the ballscrew can be replaced with ABEC 9 608-ZZ. The ABEC 9 608-2RS have a very tight plastic seal and would be a good replacement for the ZZ to get a long life during milling, they just have more resistance due to the tight seal, so they don't spin as freely. Can you tell me, what let you to diagnose that the bearings are bad? What types of material do you mill? The outside bearings LM12UUs are a known issues because they can be over tightened, but I've rarely heard of issues causing a need to replace other bearings even after countless hours of milling.

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I've only done a little milling with 2x4 scraps to get used to the machine and fusion cam. I made a couple of deep cuts early on and crashed into my shopvac hose once. I got the cable snagged while levelling the bed. It was after that that I noticed the outside bearing dragging. It was after removing that bearing and turning the ballscrew by hand after removing the belt that I realized the other bearings were noisy. The plastic seals on the ends are trashed and the ballscrew bearing spilled it's contents upon removal. I did notice a little corrosion on the outside bearing where the setscrew sat. The machine had sat in a warehouse for almost 2 months before I picked it up but everything looked great when I opened the box and there was no sign of the customs officers being rough. I think the outside bearing snagging put torque on the other bearings and caused failure. My x axis is still smooth and I haven't noticed an issue with z yet. The bearings on the quick change head sound dry, if that makes sense.

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John Hancorn will be eternally grateful.
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