Warning, I trashed LM8UU installing Y-axis bed stabilizers

[Tdeagan]

I was just installing the Y-Axis bed stabilizers from Printrbot. The fit on the LM8UUs was _very_ tight. I added compression from the 4 screws, but the wood warped enough for the pressure not to be even. When I attempted to re-insert the Y-axis rod, the back bearing wasn't truly aligned and as the rod was pushed forward, the back bearing spewed it's tiny ball bearings out the back

This was really my fault, I should have retained the rods in the bearings as I mounted them in the frame. I'm writing this as a warning to others to remember to do the same.

New LM8UU's on order. Be careful not to order the sneaky LME8UU's that slip themselves into search results for LM8UU's.

[Tdeagan]

Follow up on my post-of-shame above.

I received new LM8UU's from Ultimachine (great purchase, good price, fast shipping, some bonus PLA and a sticker thrown in the box!)

The Bed Stabilizer brackets are much tighter than the top plate cutouts for the LM8UUs. Screwing them down so that the distance equaled the provided standoffs made everything so tight that the wood bent and the rods ran stiff through the bearings. The job of stabilizing the LM8UUs was accomplished without anywhere near this much pressure, so I backed off until everything balanced out.

Trimming the rectangles that the LM8UUs fit into would really help, but I didn't want to trim unevenly, so I didn't go that route.

Last note, I really wish I'd lubricated the LM8UUS before I reassembled the bed. This at Reprap.org talks about strong improvements using white Lithium (whcih is what I use on my Z screws.) Unfortunately, if you don't apply to the inside of the bearings before you insert the rod, the rubber wipers at each end of the bearings removes the majority of the lubricant if you apply it to the rod.

All in all, the bed is a very rigid now. It does have more resistance than I had using the zip ties, so I may have to tear it down and work it some more in the future.

I did need to make it fit with my , but that turned out to be a non-issue.image.jpg

[Mooselake]

You're not the first one to lose your balls

If you can handle a little longer wait is a good eBay source that several here, including me, have used.

I believe the only Pbot supplied bearings on my bot are the 12mm Z bearings as most of the original LM8UUs wore out, the other one had a higher pitched voice and got replaced. I ordered a set of LME12UUs for the Z, but found that cleaning and relubing with teflon based grease fixed the gritty problem. They're still in the spare parts box.

Kirk

[Tdeagan]

Thanks! I just ordered an extra set from them. The new ones I bought are already making truly horrid clacking sounds! I think one or more of them dropped a ball bearing along the way.