Chinese Linear Slide Bearings - Something to watch for. 

These are not precision parts, even on high precision linear guides you don't locate them this way. Counterbore instead of countersink and leave 0.5-1mm clearance (20-40 thou) to allow for any misalignment. You only experienced issues because you assumed your method would be better than the standard way it's done.

This just saved me weeks of waiting for ordering new slides that I thought had worn out. Turns out every single one of them was machined slightly different, and I just had to account for that on my slides. My machine now has never ran better. Thanks a million!

This video [and the comments] are EXTREMELY helpful, and interesting to me - I genuinely learned something! Thank you!

Thank you so much for sharing. We all learn something every day. We, humans, start with learning how to talk, and then by talking, we can share information. Unfortunately, there are some people that learn how to talk mainly to criticize rather than to share information they possess. Thank you again.

Great video. I plan on getting some of these. Thank you for the tips. Agree that the whiteboard on the cabinet doors is genius. I've never seen that before. Makes so much sense. Keep up the great work.

Thanks, this will help me in the future. On some of my projects I will use flat head screws, on metal. Just trying to engage more surface area ( especially on thinner metals ) with a fastener, but it doesn't always work to my advantage. I feel your pain. I want to build a router also. Thanks for sharing!

Intresting video, thanks. i use these thing's on my 3d printer. But i made the holes in my carriage oval, and used washers with my bolts.

All this time i thought it was me not measuring things right. Thanks for confirming how crap some items really are!

hi mate. IV been looking at these units on AliExpress so this video was great. One question- you mention lash adjustment- how is this done with these bearings? do you deliberately push them out of square in relation to the rail? I haven't had any exposure to them before so any information much appreciated.

Funny you should bring this up, many years ago I worked on a project with another person and the holes in that component were all marked out, drilled and then countersunk.........the result was that the c/sinks aligned the screws exactly to the hole centres, whereas being hand drilled from marked off centre punched points the hole centres drifted with the drilling........this was found out after a lot of head scratching and resulted in counterboring the holes with clearance around the screws.....they lined up and were later dowled in place. I came across this phenomena many times in later years when holes that had clearance were then countersink......it works OK for through holes that have parts bolted together with nuts and not tapped, but NEVER when the second part is a series of tapped holes,

Thanks. I am just about to do that. Think you saved me a heap of headache. Cheers

Dude. Your cabinet doors are maybe the most awesome thing I've seen all month. Kidding, they are definitely the most awesome thing I've seen. Good video, but I really love the doors.

I recently made PC gaming rudder pedals using the same slide bearings shown here. I ran into the exact same problem plus one more. On only one slide 2 of the holes were approximately 8mm instead of the 6mm that all the others were. I ended up redoing the plates that they bolted onto to compensate for the shoddy placement and buying 8mm bolts for the oddballs. Autozone just down the street had the 8mm bolts saving me wait time on ordering them. Next time I order I'll definitely avoid the cheap Chinese slide bearings.

Priceless info thank you

For what it's worth, this would have caught me out as well. I would have done the layout on the mill as you did and assumed the screw pattern was on centre.

I'd design out the need for accuracy. Use oversize holes and let the guides themselves determine where they will sit. Means ditching the counter sunk head screws.

Thx for that. I’m about to assemble the same parts

yeah I was always skeptical of these types of rails.. that's why I'm going with HIWIN rails...would love THK rails but I can fit my whole cnc with hiwin for the price of 1 thk rail and set of blocks

Interesting -- I just came up with the same problem. Not sure yet the solution will be the same. I used counter sink holes because my plate was not thick enough to allow counter bores knowing that there could be problems with the counter sink holes. Yup not precision parts. My ball screw nut housing had all the holes drilled off center. Had to drill and tap new holes on the other end of the housing.

Thanks for your help!

great video! thanks for the heads up, think i'll go for HIWIN rails

Thanks for your Feedback Mr America, I will order my workers to make a new patch. 反馈已收到，我们会尽快发布补丁。

I know what you are talking about brother, and it's frussssssstrating. I suggest that you use counter boring instead of countersinking. A countersink screw's head is never concentric with the thread which adds to you problem of the holes being out of position. With a counter bored hole you at least have some clearance to play with. I'm glad that I watched your video which made me aware of this problem because I'm going to use 26 of these bearings (20 mm) on the CNC mill I'm busy with. I intended to counter bore the holes from start.

these bearings are okay, you just have to set them individually, instead of designing holes without the possibility of matching, if you will order hiwin is a great choice, but also leave yourself tolerance for matching,

The simple solution, albeit a little time consuming, is to instead of having countersunk holes, have counterbored slots, so you can make those small "micro adjustments" to get it all aligned, then red Loc-tite all the hardware.

Where can I get the saddle?

holy shit dude. you look EXACTLY like my schoolteacher for Car Mechanics

Thanku for the video.

I am building a similar machine but I am not precission milling because I dont have the gear. It is a bedroom build with bosch aluminum. I have aluminum plates but with straight holes a bit large and wahers to lock. I square up the plate with dial guage and calipers. Mind you I only want to do woodwork and heavy carving

Thanks for this video, i will be getting German bearings for my project then.

thanks. i'm about to order a couple of these bearing blocks from ebay.

Is there any noticeable difference to having the rails mounted on top of their respective locations or the side? Is there an advantage to the amount of “play” or slop in mounting them one way or another in your opinion? Thanks!

Yes me too I have that problem that's why I sold it and I buy the hiwin linear rail

What's the diameter of the shaft you're using? I've seen 8mm, 12 mm, 19mm on wish. But the description isn't clear as to diameter and length. As well as what is included. I want to change my three axis mortise machine from full extension drawer slides to the linear bearings you are employing. And you're correct. My application isn't near as critical as what you are striving for. Who do you recommend ordering from? Thanks Very informative, nice work.

There's actually a use to the “problem“ you have. This is very common in linear guiding systems. The holes are hardly ever centered on the Slides. There is almost alwas a Stop-Edge on these. But only on one side ! From this edge you have a certain distance to the center of your Rail. So you could Mill another Stop-Edge on your Base-Plate and push it against the Slides. Sorry for my bad English.

how much load can those rails hold?

Yup i was having the same problem the 3 holes were fine one was off i thought it was me but im glad i see its not me

Is that the sbr12uu bearing? If so, do you recall what the pitch and size of the tapped holes are? I am trying to research and finding all kinds of answers! Thanks

I own ezcnc in Plano Texas. We fix a lot of Chinese machines. The knock off hiwin parts are not worth the savings. I have had to fully rebuild brand new machines that customers bought from places like industrial Cnc that imports from China. Spend the extra for hiwin, thk, Iko, or Thompson. You get what you pay for. Same with electronics. There is a reason why Oriental motor stepper motors cost more than parts bought from amazon or eBay, they last and have much better power. It’s what is inside that matters.

Common practice on setting up your rails, not the slides, the rails is to mount just one side first. Then use your plate with all four linear bearings to align the 2nd rail and everything becomes aligned with eachother.

Buy Thompson rail. It’s the original and consistent. It’s also Mayse in in USA and Mexico. The difference is amazing. The stuff on amazon and eBay is cheep for a reason.

Kuality with a capital K. The parts are from China. Gotta make up for the lack of QC. Counterbore and an oversized bore is the way to go. Adjust the fit as necessary and they'll be fine. You'd think they would just CNC the little buggers but no ... 😳

hello what is the precision of those rails? i want to make a lathe bed out of it

Hii there can u tell me when u will apply force by side not front by side, then will it go little bit side site or not I'm talking about in micron length

How big are the linear rails over your table, the longer ones ?

Will these chinese rails and bearings hold up if they constantly get wet?

I’d like to fit a swivel vice on that plate any ideas. From anyone here. Cheers

I had same problem but made it work Rails worked good except for set screws keep falling out.This is because of our great partner, China. When I buy my next set will look at better quality, even if twice as much. Have toyed with idea of filling holes and reboring.

How much does your os Together with the spindle?

does anyone have any recommendations for getting smooth and ultra quiet bearings for rails like these?

can you make me a x y plate using. the bearing for me

Bearings were probably sorced from different factories. or home workshops (cottage industry). If you want good bearings you will need a big wad of cash.

hi, i just bought my lead screws from banggood,come with brass TEE nut,got some anti backlash nuts too,that's it,for a machine like this or smaller (mine) bearings guides can be made easy,using european or just plain "WESTREN" made bearings,i did search and found the fully supported tyes here,but people get good accuracy from drawer sliders,though for this machine and the one(s) i want ,sealed ball or roller types by skf etc,running on square tube mounted on some stiff aluminium extrusion is super easy,AND the parts are cheap to replace,my big problem is shipping,ot the cost,but the damage that can be inflicted on a length of bearing rod,supported or not,it's bad enough i have to wait to see if my 8mm x 2mm lead spacing screws come bent,at 700mm long for the Y axis it can be ruined easy by a moronic sender or carrier,i hope they are supported,but they are cheap enough,with the fittings i got and bought i can ,though i don't want to,get them closer,but for quite a bit more,plus insane p+p,free from china!!!!,yet more from a euro dealer,i digress,linear slides/rails of a supported nature can be made cheaper and better,unless your machine is for ultra super accuracy to the Nth degree,like i mention ,i've seen realy good resolution from goofy looking builds all over youtube,a good set of tools and some brains can go along way,plus the machine when done can make parts we humans can only dream of making(accuracy wise).

rails I just bought should have fixing holes 5mm , one rail did the other was all ~ 4.8mm, wow.

I know this is old but do you have the hole layout dimensions or a template for the slides?

Not being a machinist, no CNC, I am a little befuddled on how to register the holes on the bearing to a support plate. Makes me not want to save a buck on chinese linear rails and bearings. The USA version is 6-7x more expensive. Looking at 80/20 linear bearings as an alternative.

Totally agree...you never mount linear bearings with countersinks....Also the distance from the outside of the casting to the center of the hole means nothing. Its the center to center distance on the holes. Since you went to a machine shop you should have give them a positional tolerance on all your holes as stipulated in ANSI M14.5-2009.

How do you lube those bearings?

Thank You for the great info......I probably would have ripped my hair out....lol

What is the brand name of these, so I and others can avoid them??

One sentence would have sufficed; the holes in the bearing block are not drilled symmetrically with the bearing! i.e., they are offset from the bearing.

you measuring out size. that should not matter at all toleranse could be 1inch if that fits. bigger issue and that should be correct is holes should be in centre of bearing. block can be any size out even not square if mounting holes is paraller to railing and centre. there is problem if they make it using sides to make them and not centre. you can try flip bearing housing and see will if holes go other size. then they not centre. order new ones they cheap that whats you get sometimes. no panic order many extra still cheaper than good quality ones. and its only mounting holes you can move holes on plate

Wow, that's terrible quality for a production manufactured part. I'm sure the vendor would send you a replacement if shown a picture of it. I know it sucks waiting on parts during a build but sometimes patience is worth it. Makes you wonder how many hundreds slipped through quality control checks before being caught. With modern production methods those holes dimensions should have a tolerance of a few thousandths at most.

Flip the plate over and use socket head bolts

I have to said even those thing only cause few dollar on eBay, you might thinking the quality should be the same few dollars, but NO, these parts only cost 1.5 RMB and free shipping on TaoBao, which is same as 25cent on US dollar, they turning to couple dollars on eBay because the shipping or other costs, but the quality you should think as 25 cents, so what I thinking is that quality is ok for it’s price, but not fair to the people outside of original place

Thanks China

Use Thompson rail and blocks. They are worth the extra. Consistent from part to part

Check the installation manual of a reputable manufacture for installation instructions.

I used the same slides and had the same problem until I figured out that there is a left side and a right side to the bearings.

and i thought it was me.... thanks

I got a set of them and as far as I can tell there is no two alike .,.

4:14

It was visibly out.

Thanks for the info. I probably wouldn't have countersunk the screws with a tapered head. Maybe a counter bore with allen head bolts to allow for the noted imperfections. Grrr! Cheap Chinese products!

You just can't make a blanket statement that all Chinese slides or like this or even bearing housing if it's a particular model then maybe but still none the less maybe it was just a bad batch or lot also ... js

Had exact same thing on the black ones for ballscrews. You cant tighten it..its damn sideways and seller didnt gove a shit. I advise you buy custom or local or use paypal and hit em for not received as theyl offer you peanuts and they wont replace so be careful. I bought 3 and 1 was like that.

Thanks for taking the time to do this video. good reviews on cheaper stuff is always helpful. So I'm wondering if you think these things would be strong enough (or suitable) for a small camper slide out like you see in this clip ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ot-lf_lMLDA.html. I'm looking into building something similar to this trailer and I need the slide for my queen (and her queen bed).

I have those rails and I'm am going to upgrade to proper rails not these are fine for a router up to aluminium machining but steel nope the have some wiggle room in them

Normal people: "close enough." Machinists: 4:48

Greetings, I notice the same in these "chinese" parts, those are not equal at all, and random holes position, so, the chinese make each fo these linear bearings UNIQUES, a complete crap. Can You advise some place where GOOD CNC PARTS are sell? Thanks in advance

We can only blame ourselves as we shouldn’t have to rely on the Chinese , we should be manufacturing our own at a competitive price.

They all have that same secret, the more expensive the less obvious. The tech sheets will tell you to mind the orientation.

COUNTER BORE THIS IS HOW I DID MINE EASIER SETUP. MY MACHINE IS MADE FROM 3/4 THICK ALUM... VERY HEAVY AND RIGID.TOP SPEEDS ARE 150 IPM SAFELY .640IN/OZ MOTORS.5' X 48" WORK SIZE..

You get what you pay for. To avoid the "issues" you have you must pay 10 times more for precision parts, so what do you expect? Besides, use socket screws with washers. The screws you have used are NOT the right type for the purpose, not even if you super glue them with loctite.

So this was a surprise for you??

6 Min to say I had to rotate the plate! 10 seconds done! lol I was waiting to see if it was a big deal before I ordered. NOPE!!!!

Never underestimate communist Chinese precision! it's like USSR precision, it is pretty similar. Now imagine buying combustion engine parts. Yes you guest it it was a phukin rolling the dice. By the way i am either russian nor commie or chinese. How do i know the commie engineering well, my friend wonted to go exotic on a motorcycle so he bought a Ural :). He would be much better off with a polish Junak butt they are very rare.

You probably should not have used flat head screws.

they look chinese very pricy rails. try flip them holes might match or atleast put them same orientation if they are very high quality cheap lol

Your video is 6,5 minutes too long. "Hi guys, I slided 1 bearing over the wrong way round, silly mistake." takes 6 seconds.

Old chinese saying, 'best time to rob your neighbor is when his house is on fire'.. pretty well sums up the care factor from cheap chinese products, of all types!

creepy

I destroyed 2 of them

no big deal

They are no good for CNC metalworking. Buy Japanese instead.

Thank you so much. I was just about to order one. Now i will only buy USA made. They are exporting junks from China.