2PCS 8mm X 150mm Linear Motion Rod Shaft Guide with 4 PCS SCS8UU Ball Bearings & 4 PCS SK8 Aluminum Rail Support, Linear Motion Rod Guide Set for CNC and DIY Craft Tool (Diameter 8mm, 150mm)

It's very nice and made very well. I use mine in a alternate way but they are still nice. Great for small projects that need some precision.

The ends of the rail look like they were cut on a horizontal band saw, and the corners chamfered with a bench grinder. That said, I don't feel any burrs. They are not the same length either. One measured 7.912", the other 7.946". No dings blemishes or bends though, so fully usable.The linear bearings and rod brackets fit and move beautifully. No problems there at all.

The reason I purchased these were to use them as guide rods for an air cylinder. I designed mounting brackets based on standard dimensions for a SCS8UU linear bearing block but the mounting holes on these parts do not match the standard hole pattern; specifically the "C" dimension as seen in the photos for the product. I only found this out after I had parts made. The ball bearings of one of the LB also fell out after sliding the rod into bearing. The mounting holes of the block itself are also not orthogonal to the surface. I would not purchase again for any serious projects although they might be suitable for any proof-of-concept prototypes.

Lots of slop in bearings, no chamfer on guide rod ends so the edge caught when I was installing it and blew all of the balls out of one bearing. Imprecise machining on mount ends, some completely crooked. For the price they will get the job done, worth it at the end of the day. Glide is a little rough horizontally but still totally functional. Tip: after putting bearings on shaft, don't remove them unless absolutely necessary.

Only received the 2 rods. Package had been previously opened.

The linear rods were warped.

The first "Linear Motion Rod Guide Set" had a sticky SCS8UU bearing, which Amazon promptly replaced. The two Rod Shafts have a slight burr on each end and I would recommend gently belt sanding each end flat and redoing the chamfer so the linear bearings can be installed easily. It is also recommended to use a machine oil to lubricate the bearings before installing the rods; I use sewing machine oil. The bearings are a little noisy when sliding them at a fast speed. Overall the set is a good quality and I'll probably purchase them again for another project.