BQLZRSC8UU Linear Motion Ball Bearing CNC Slide Bushing 34.5mm Length Pack of 4

Great for their cost. Sure they are cheap and maybe they had a couple of rough motions at first, but that worked out. I wasn't willing to pay McMaster-Carr prices for my slide and I knew that I get what I pay for. I say they are great for the price.

Worked for what I needed. I purchased them as replacements for the ones that came with my 3d printer (a Prusa I3 clone). I knew they would probably be similar quality, especially given the price point of the printer and the bearings. Some of the ones that came with my printer had all the ball bearings fall out of the assembly. I don't know if it was the way I inserted the linear shaft, or if they were cheaply made. I was hoping it was just one bad bearing but it happened on a few different ones, and also on one of the ones I purchased here.But the ones I have on my printer now are working fine, one I had the shaft on them, I don't have to worry. They seem to slide ok, a little rough, but again for the price, I don't really have a complaint. I know high precision bearings cost a lot more. These worked for what I needed them for.

The media could not be loaded.  Construction is excellent but the friction to movement was about 25g. For your application that might be no problem. For mine it was a deal breaker.

They didn't sound good at first but that seems to have cleared up after some use.

Screw holes are inconsistently sized. Most fit for M6, some are a little larger, threads dont 'grip' and screw just turns instead of tightens,. With one of the blocks the screw holes are tapped larger than M6 and the screws fall out.Other than being unable to fix the blocks to the Y-plate without a larger screw and affixed bolt that interferes with the printers frame, these do slide up and down linearly.Get what you pay for.

While have not had much luck with cheap 8mm bearing trucks. I purchased a set of these and they worked perfectly. Both smooth and without play.I will be purchasing more from this vendor.

Partially tapped holes limit you to only top mounting. The wholes are not square on all blocks. Some of the bushings are missing 3-4 ball bearings making them jerky. I guess for $8 you get what you pay for.EDIT: Bought a second set because the 1st ones were useless. These came with the bearings on the outside! Loose in the bag, so... again completely useless! The seller NEVER response to emails and shipping to return them costs more than they did.

First of all, the bearings in these are total garbage. They wouldn't slide smoothly at all on a hardened steel shaft. So I swapped them out for some nicer bearings, and all was well.Second, the mounting holes are not threaded their entire depth, just the first couple millimeters. The threading also wasn't straight on one of mine, but off at about a 15 degree angle. If you need these threaded the entire depth, you need to buy an M4 tap to go with it. Just be careful you don't follow crooked threads and break your tap.Finally, these still have a rough cast finish. The bearing surface really needs to be milled flat, which I did on a little desktop milling machine.After my modifications these were decent, but as they come out of the box there are unusable. Don't buy these unless you plan on fixing a lot of flaws.

Bought it for a future project. Looks to be a good product.

-Internet Auftritt übersichtlich gestaltet;-Auswahl didaktisch gut organisiert;-Zahlung mit PAYPAL bequem; -Schnelle Lieferung;-Ordentliche Verpackung;-Qualität wie beschrieben und erwartet

The media could not be loaded.  QUALITà ECCELLENTE ! comprati per costruire uno slider fai da te perfetti per fare tantissimi progetti ! il prodotto come sempre è arrivato subito con corriere , la qualità del prodotto è ottima i cuscinetti fanno benissimo il loro lavoro super soddisfatto , come ho scritto prima potete usarli in mille modi ! buon divertimento ! Dimensioni prodotto 8,9 x 7,9 x 2,5 cm CONSIGLIO L'ACQUISTO A TUTTI GLI AMANTI DEL FAI DA TE come me

¡Me encantan! Me vienen mucho mejor que otros que compré pero que no tenian una sujeción como tienen estos, así que los cambiaré en el "fuerzómetro" que estoy haciendo para medir el empuje de los motores eléctricos de aeromodelismo.Recomendados con barra de acero calibrada para un óptimo rendimiento.

Would be 5 stars except they are only tapped half way which is kind of inconvenient.