10 Pieces 8 mm Bore Diameter Pillow Block Ball Insert Bearings Rail Mounted

Good quality. Works well.

1. they are cute. 2 they are fairly inexpensive, 3. loose, noisy. 4. slop is about .1" (2.56mm) at 3" from bearing. Ok for simple prototype applications. Works for my needs.

They worked perfectly for what we needed. Used them to build a teeter tottering for our goats.

It is remarkable how well they struck a balance of being the cheapest possible quality while still basically working. The bearings themselves have an enormous amount of play in them, they wiggle around like crazy, so don’t use these for anything that needs to have precision. As usual for pillow blocks, the bearings are gimballed inside the block, the reason for this is that if the mounting holes are just a bit off from perfectly square to the shaft it still works because the bearing can twist inside the block. These ones in particular, the bearings are very very tight and sticky in the block. If you put a shaft in and tighten it down, you can use that to unstick the bearing. It helps to put some light oil in there. After you get it unstuck, if you move it around through the whole range of motion for a while it gets much smoother, but still not what I’d call smooth or precise. But if you have a basic need for something with an 8mm or 5/16” shaft to be held mostly in place and spin around while having some wiggle room for alignment, I think these will do the trick just fine. As for weight bearing, I wouldn’t put any heavy weight on it and nothing mission critical, but I think they are actually quite strong for hobby purposes. Like, you wouldn’t build a scooter with a 8mm axle anyway, not even for a child… so these will probably be strong enough to hold the weight your hobby project requires. Just keep in mind they will wiggle a lot, so they are not suited for things like 3d printers that need to be precise and repeatable. You’ll definitely need to pay 5-10 times as much to get bearings with the level of precision you need for a 3d printer. But for the price these are a great deal for your basic low-precision bearing needs… which is exactly what I needed!

So far no issues, works well for my needs. Used to create a hinge for a door into the garage attic.

I wouldn't recommend these bearings. This type of pillow block bearing has a ball joint that swivels to allow for minor misalignments. When I got them out of the box every single ball joint was stiff and immovable. I took them apart and used degreaser to clean all the little metal shavings out from the casting. I lubricated them and put them back together and they are all still very stiff. The ball joint needs to move freely if these are to work as intended. I will be buying different bearings to replace these.

On every pillow block, one of the set screws must be cross threaded. About half I am unable to back out at all, and the rest are just a pain.