Ok! This has taken me a bit to work out what was needed and

Ok! This has taken me a bit to work out what was needed and find it… So here we go…
THIS is, according to both RepRap and local linear bearing experts, the correct type grease to be used for any 3d printer that uses linear roller bearings.
An NLGI 0 or 1, lithium thickened/soap grease with no PTFE or Molybdenum(both might work under high load, but not here). This is a ‘OO’ grade. It’s got the consistency of mayonnaise.

Heavy oils(80W and greater) work, but they do tend to escape from the seals and need frequent reapplication. Any thicker grease(For example ‘superlube’(Despite what it says) or NLGI 2+ grades will cause the balls to stop circulating.
Just searching for ‘semi fluid grease’ will find it for you.

For those who don’t know. Most of these printer linear bearings are ‘under-loaded’, so there’s rarely enough force to make the balls roll(They should make a quiet ‘whizzing’ noise when running as the balls roll, try pushing down on your bed in a traveling bed printer(Or any other axis that is convenient) and moving it back and forth, you should be able to feel them move). Especially in the Z axis. In many printers they are little more than glorified bushings, riding mostly on the oil seals.

My big question is why can’t I buy little tubs of those from places like RepRap Discount, e3d or any other 3d printer supplier that stocks bearings. If they sell open linear bearings, they also should sell the matching grease! This tube cost me AU$13 and that will last me until the end of time for my printer. Sell it in 50ml tubs and 10ml syringes!


Can this be applied once assembled? (ie: spread it on the rod and have the bearing pick it up) or do you have to remove the bearing and manually spread it inside before reassembling?

Any sources in the US?

@Alex_Wiebe unfortunately not. You nee to pull out the rods and ‘pack’ the bearings. Ideally first degreasing. :frowning:
@Keith_Applegarth no idea. But most grease manufacters seem to make a ‘semi-fluid’ grease. Do a search for it and when you know what it’s called and try your local automotive shop. This is why I’m surprised you can’t get it from any printer shop. :frowning:

I will check and post back.

@Electra_Flarefire why don’t you offer said options? In an attempt to help other makers, in such a way that you’d get back your investment and with the buyer taking the shipping costs.

Shipping small amounts of random goo around the world might get messy. (MSDS labeling and all that…)

This would be something someone like @Brook_Drumm should look into - maybe include a little canister with each printer and offer more in the parts section of the Printrbot site.

@Adrian_Ciubotariu because I’m very bad at running any sort of business, even like this.
I’m emailing a few local 3d printing places and offering this idea. I mostly want this sort of thing to become available after seeing more than one printer owner trash their machine due to lack of lubrication.

@Electra_Flarefire ​ don’t I know it! I had to redo my x axis “thanks” to improper lubrication.

The proper lubrication helps with any materials, either sliding or rolling. Most of the cheap printers use a very cheap bearing. If you were to view the balls of a cheap linear bearing under high magnification, you would see that they are very rough. This roughness is what you hear as you move the bearing. Round, smooth balls don’t make noise. The challenge is that good bearings are expensive and probably not made in China. My son and I have replaced all the linear bearings in our cheap 3-D kits with teflon bushings. They slide with less resistance, are quiet and provide adequate tolarances.

I plan to eventually replace them with bronze bushings. But for now the rollers work enough and finding the right grease should mean they’ll run and work for some time.
The following should be almost drop in replacements on my i3.


Oh… And even the very best bearings make sounds. I have some extremely well made and quite overpriced sealed skateboard roller bearings that make a beautiful ‘Ffffffizzzzzzzzzzz(etc)!’ sound when spun and if they are used on any mass you get bored of waiting for them to stop(used on my spool holder, to minimize load on the extruder). Because they are lubricated with a medium oil, rather than grease. A grease adds rolling resistance and also dampens the balls, making them quieter. The biggest problem with this approach(And a heavy gear oil /does/ work well) to linear bearings is that the oil does escape and you have to reapply quite often, dismantling the printer to do so!

@Electra_Flarefire I shared this with my dad, who commented above, because I found it interesting how we both started out with the same Prusa i3 kit of questionable quality from 3dPrintingCzar, and our printers have diverged wildly. Perhaps similar to you, I have a goal of replacing every printable part, as the infill used in the kit was insufficient for some parts, probably 15 or 20%, and I think I read somewhere that 40% is recommended for at least the Prusa i3 kit. I will have to share you a picture of ours when I get a chance…all the original linear bearings are gone as @Dave_Buaas mentioned above, many of the printed parts have been replaced, and I am currently in the middle of replacing the frame (ug) with aluminum water-jet cut pieces, mainly for better rigidity and heat tolerance of the Y carriage. I believe I overheated the acrylic Y carriage plate that came with our kit and warped it. Anyway, glad to hear you found some good lubricant that works well for your linear bearings. Are you still using the same ones as the kit came with? Some of ours, particularly ones on the Y axis, were dragging badly very early on, so we machined some bushings out of teflon on a lathe.

@Tom_Buaas I’m using some of the original bearings, I got a handful of extra ones and selected the best, plus I’ve been keeping them lubricated from the start(after degreasing them of the anti-corrosion coating they came with). They are sometimes a little noisy, but are holding up well enough for now.
I also plan to replace the main frame with Aluminium, but mostly to give myself another 50mm of build volume in each dimension.
The Y plate for now i’ve solved by adding spacers to make things more rigid and some descent under-bed insulation that also gives me a better heatup time and uses less power, but the acrylic parts will end up being replaced in the size upgrade.
The only original 3d printed parts are the Z and Y motor mounts, the two rear Y carriage mounts and the y carriage belt-holder-thing. All these have either not failed or have been working well enough. :slight_smile:
The Z rod mount tops have been replaced now too(after photo was taken).