Glvanc, 3D Printer Guide Rail Sets T8 Horizontal 8mm Lead Screw + L200mm Shaft Optical Axis + SCS8UU Linear Bearing + Pillow Block Bearing KP08 + Shaft Coupling + SK8 Linear Rod Rail Support 16Pcs

I bought 2x500mm and 1x300mm. Between them I was able to make 2 sets with barely okay bearings and 1 set with awful bearings, the latter will go on the less used z-axis of what I'm building.The bad linear bearings are a range of jumpy and lumpy, to outright just skidding along without internal movement. I greased them up and hope for the best. 1 of the 500mm rails isn't as uniform as it should be, as the linears hit a point and require a bit more force to get past that bit, no doubt I'll have to locate and sand down that bit later.If I had the money to buy real parts, I would. Instead I've bought these 'cheap' parts (which the price dropped 23% immediately after buying - f-ers) which will just about do, but will not do for anything that will get a lot of use. I wouldn't use these on a 3d printer. I seriously considered sending them back, which is a rarity for me. the only thing that stopped me was that I was able to make the 2 okay slides and lets be honest, you get what you pay for.

I took what I thought was a bit of a risk given the poor reviews on this item, but can't fault the parts much now that they have arrived. All the shafts and leadscrew are straight. There is a little bit of play/backlash on the brass nut., which is normal. The slide carriages are also not super-tight and have a little play, but once mounted that goes away (note that there is no adjustment available on these). The only thing that does need some remedial attention are the bearing pillow blocks, as the bearings are not aligned straight and perpendicular; although, these can be tapped into place with a drift. I have had more expensive pillow blocks that have also needed attention so I guess it's common.

I have a problem with the circlips that have been used to retain the bearing into the guide bearing. The circlip fasteners (2 holes where the clip pliers fit) are oversized and scratch the guide shafts meaning they won't slide freely. I'm going to have to remove and grind the clips so that they don't restrict movement.

Looks and feels good quality but ball bearing were completely unusable. Movement along provided rod was rougher and grittier than sandpaper in all but 1 of the SCS8UU bearings (which while being 10x better than the other 3, was still comically bad). Definitely cannot recommend this product for any practical applications.

An excellent assembly . . . My application is intended for a unique product, not yet design released ! . . . Further design modification to finalised design yet to be reviewed, but so far, so good.

The bearings are absolutely atrocious. The movement is rough and gritty, in fact they feel very similar to a bearing that is broken. They are so bad that they are absolutely useless.

Good

500mm T8 Lead Screw is slightly bent causing brass nut to move by about 5mm side to side as screw rotates. The linear bearings are noisy and run rough. The rods, mounts and pillow bearings are okay. I'm going to try and straighten the lead screw and improve the bearings. (any ideas of how to do these ?)